UTICAJ HRONIČNE STIMULACIJE TIREOTROPINOM NA NODOZNO IZMENJENU ŠTITASTU ŽLEZDU 49 Dr Sanja Medenica Prof. dr Božo Trbojević UTICAJ HRONIČNE STIMULACIJE TIREOTROPINOM NA NODOZNO IZMENJENU ŠTITASTU ŽLEZDU Sažetak: Uvod: Nodozna struma je klinički prepoznatljiva ograničena promena građe štitaste žlezde. FNA je prva linija dijagnostičkih testova kod uvećane štitaste žlezde. TSH je poznat kao tiroidni faktor rasta, ali patogena uloga ovog hormona u tiroidnoj onkogenezi je nerazjašnjena. Materijal i metode: Retrospektivno je pregledano 637 tiroidnih FNA citoloških izveštaja uzoraka, dobijenih punkcijom pacijenata sa tiroidnom nodoznom bolešću Odeljenja za štitastu žlezdu, Klinike za endokrinologiju, dijabetes i bolesti metabolizma, Kliničkog centra Srbije u Beogradu, u periodu od oktobra 2007. do januara 2010. godine. Analiziran je odnos između dijagnostičkih kategorija citopatoloških nalaza i serumske koncentracije TSH. Podaci su statistički testirani Kruskal Wallis testom razlike pomoću kompjuterskog programa SPSS 12.0 softverskog paketa. Rezultati: Od ukupno 637 pacijenata 3,45% (22/637) je imalo maligni, a 4,87% pacijenta (31/637) neodređeni citopatološki nalaz. 91,52% (583/637) pacijenta je bilo sa benignim nalazom, i samo jedna neuspela punkcija. Prosečna vrednost TSH u grupi pacijenata sa malignom dijagnozom iznosila je 9,83±17,48 mmol/l sa medijanom 3,31 mmol/l. U sve tri dijagnostičke kategorije (benigno, maligno i neodređeno) najviše je pacijenata sa referentnim vrednostima TSH, ali postoji relativno veća proporcija, 27,3% (6/22) pacijenata, sa malignim citopatološkim nalazom kod grupe pacijenata sa povišenim vrednostima TSH. Postoji statistički značajna razlika između dijagnostičkih kategorija po grupama vrednosti TSH (χ²=8,136, p=0,017). Zaključak: Zaključuje se da rizik za razvoj tiroidnog maligniteta raste kod pacijenata sa povišenim serumskim koncentracijama TSH. TSH treba koristiti kao pomoćno dijagnostičko sredstvo u identifikaciji visokorizičnih pacijenata koji zahtevaju dalja ispitivanja i/ili hirurški tretman. Cilj: Cilj rada je da se analizira veza između povišenih vrednosti TSH i tireoidnog maligniteta kod osoba sa nodozno izmenjenom štitastom žlezdom.
50 MEDICINSKI GLASNIK / str. 49-56 Ključne reči: nodozna struma, tireotropin, aspiracija tankom iglom Abstract: Introduction: Nodular goiter is clinically recognizable restricted structure changes of the thyroid gland. FNA is the first line diagnostic test for an enlarged thyroid gland. TSH is known as a thyroid growth factor, but the pathogenic role of this hormone in thyroid oncogenesis is unclear. Objective: The aim of this study is to analyze the reltionship between elevated serum TSH concentartions and thyroid malignancies in patients with nodular thyroid goiter. Material and Methods: We retrospectively reviewed the 637 reports of thyroid FNA cytology of samples obtained by puncture of patients with nodular thyroid goiter, at Department of thyroid gland, Department of Endocrinology, Diabetes and Metabolic Diseases, Clinical Center of Serbia in the period from October 2007. by January 2010. year. We analyzed the relationship between findings of cytopathological diagnostic categories and serum concentrations of TSH. The data were statistically tested using Kruskal Wallis test of differences using the computer program SPSS 12.0 software package. Results: Of total 637 patinets 3.45% (22/637) had a malignant, and 4.87% patients (31/637) cytopathological indeterminate findings. 91.52% (583/637) patients were with benign findings, and only one puncture failed. The average value of TSH in a group of patients with a diagnosis of malignancy was 9.83 ± 17.48 mmol/l with a median 3.31mmol/l. In all three diagnostic categories (benign, malignant and unspecified) most patinets are with the normal concentrations of serum TSH, but there is a relatively large proportion of 27.3% (6/22) of patients with malignant cytopathological findings in the group of patients with elevated TSH concentartion. Statistically significant differences between diagnostic categories by group TSH values (χ²=8.136,p=0.017). Conclusion: It is concluded that the risk of developing thyroid malignancy increases in patients with elevated serum TSH concentrations. TSH should be used as an additional diagnostic tool in identifying high-risk patients who require further investigation and / or surgical treatment. Key words: nodular goiter, thyrotropin, fine needle aspiration Uvod Nodozna struma je klinički prepoznatljiva ograničena promena građe štitaste žlezde. Nodozna tiroidna bolest je česta i javlja se u 2 6% slučajeva otkrivenih palpacijom (5% kod žena i oko 1% kod muškaraca koji žive u jod-suficijentnim područjima), čak 19 35% pomoću osetljivih postupaka kao što je ultrazvuk i na autopsiji u približno 8 65% slučajeva opšte populacije. Prevalenca se linearno povećava godinama, izloženošću radijaciji i deficijenciji joda. Može se javiti endemski
UTICAJ HRONIČNE STIMULACIJE TIREOTROPINOM NA NODOZNO IZMENJENU ŠTITASTU ŽLEZDU 51 u područjima s deficijencijom joda, kada je prevalenca nodozne bolesti kod dece starosti između 6 i 12 godina više od 5% i sporadično kada je prevalenca manja od 5%. Češći su kod žena, nego kod muškaraca. Tiroidni nodusi mogu biti solitarni, pojedinačni ili multipli, višestruki i mogu biti funkcijski aktivni ili neaktivni. Solitarni tiroidni nodusi postoje u dimenziono i morfološki neizmenjenoj žlezdi, dok dominantni nodus postoji kod difuzne i multinodozne strume (1). U odsustvu tiroidne disfunkcije, autoimune tiroidne bolesti, tireoiditisa i tiroidnog maligniteta, formiraju entitet opisan kao netoksična nodozna struma. Kliničke forme uključuju, pored netoksične nodozne strume, i multinodoznu toksičnu strumu i toksični tiroidni adenom (Plummer-ova bolest). Najčešći uzroci tiroidne nodozne bolesti su od benignih: koloidni nodus, Hashimoto tiroiditis, obična ili hemoragijska cista, folikularni adenom, subakutni tireoiditis; a od malignih: primarni (porekla folikularnih ćelija papilarni, folikularni i anaplastični tiroidni karcinom, porekla C-ćelije tiroideje medularni tiroidni karcinom, kao i limfomi) i sekundarni metastatski karcinomi. Klinički značaj tiroidne nodozne bolesti pored estetskih izmena, kao što je zadebljanje vrata, lokalnih kompresivnih sindroma i tiroidne disfunkcije, jeste mogućnost razvoja maligniteta u 5% slučajeva. Godišnja incidenca tiroidnog karcinoma je 1 2 na 100.000 ljudi, što čini 90% maligniteta celog endokrinog sistema, 1% svih maligniteta kod ljudi i 0,5% smrtnosti zbog maligniteta (2,3). Značajni anamnestički ili klinički podaci koji ukazuju na potencijalnu malignu prirodu nodusa su: porodična anamneza tiroidnog karcinoma, prethodno zračenje glave i vrata i/ili celog tela, brz rast nodusa, tvrd i čvrst nodus, promuklost ili paraliza glasnica, ipsilateralna cervikalna limfadenopatija i fiksacija nodusa za okolno tkivo. Dijagnoza bolesti se postavlja na osnovu fizikalnog pregleda, laboratorijskih ispitivanja, aspiracione punkcije tankom iglom (FNA) i metoda vizuelizacije (scintigrafija, ultrazvuk i ultrazvučna elastografija, CT, MR i PET). Pošto mnogi klinički nalazi u solitarnom nodusu ne razdvajaju benigni od malignog procesa, potrebne su efikasnije metode za selekciju bolesnika koji treba da se leče hirurškim putem. Na taj način je redukovan broj i obim operacija. Aspiraciona punkcija tankom iglom (FNA) je prvi put upotrebljena od strane Martina i Elisa u Memorial Hospital for Cancer and Allied Diseases u Njujorku 1930. godine, mada je zbog svojih ograničenja retko korišćena, da bi ponovo postala popularna poslednje četiri decenije kada su je u Skandinaviji uveli kao prvu liniju dijagnostičkih testova kod tiroidne nodozne bolesti (4). Glavni je metod preoperativne dijagnoze kod dece i odraslih. Superiorna je u odnosu na kliničke, radionuklidne i ultrazvučne metode. Poslednjih godina dokazana je kao ključna dijagnostička procedura i drastično je izmenila klinički pristup u lečenju tiroidne nodozne bolesti. To je prva linija dijagnostičkih testova kod uvećane štitaste žlezde. Upotreba FNA smanjuje broj tiroidektomija za 50% i sveukupne troškove medicinske nege u preko 25% pacijenata.
52 MEDICINSKI GLASNIK / str. 49-56 Ključni uspeh metode sastoji se od adekvatnog i reprezentativnog uzorka ćelija i ekspertize u tiroidnoj citologiji. Klasifikacija dijagnostičkih kategorija tiroidne FNA najčešće podrazumeva sledeće kategorije: maligno, benigno, neodređeno, neuspešno. Pojam neodređeno odnosi se na lezije koje se na osnovu citološkog izgleda nisu mogle sa sigurnošću svrstati u jednu od grupa benigno ili maligno, a tu spadaju folikularne, oksifilne lezije (Hurthle cell) i suspektni nalazi. Kategorija neuspešno odnosila se na one uzorke koji nisu imali dovoljno materijala ili isti nije bio adekvatan za dijagnozu. Terapija je najčešće hirurška ili ablacija radiojodom, dok se u novije vreme, u za to indikovanim slučajevima, primenjuju terapija rekomninantnim humanim tireotropinom, perkutana injekcija etanola, laser termal ablacija i radiofrekventna ablacija. Tireotropin (TSH) je hormon prednjeg režnja hipofize koji izaziva povećano oslobađanje hormona štitaste žlezde. Poznat je kao faktor rasta tiroidnih nodusa. Supresija TSH egzogenim hormonima štitaste žlezde sprečava dalji rast postojećih i razvoj novih tiroidnih nodusa. Supresivna terapija tiroksinom pokazuje pozitivne efekte kod pacijenata sa diferentovanim tiroidnim karcinomom. Poznato je da hronična deficijencija joda, koja uzrokuje sniženje serumskih koncentracija tiroidnih hormona sa sledstvenim povišenim koncentracijama TSH, jeste faktor razvoja strume i folikularnog tiroidnom karcinoma. S obzirom na navedeno, veruje se da je serumska koncentracija TSH nezavisan pokazatelj pojave tiroidnog maligniteta kod pacijenata s nodozno izmenjenom štitastom žlezdom. Pretpostavka je da hronična stimulacija nodozno izmenjene štitaste žlezde tireotropinom uzrokuje neoplaziju i karcinogenezu. S obzirom na to da je koncentracija TSH veća kod pacijenata sa agresivnijim tumorima, veruje se da ovaj hormon ima ulogu i u progresiji maligniteta. Iz tog razloga pacijenti sa visokim koncentracijama TSH i graničnim citološkim rezultatima zahtevaju detaljnija ispitivanja i agresivniji tretman. Cilj rada Cilj rada je da se analizira veza između povišenih vrednosti TSH i tireoidnog maligniteta kod osoba sa nodozno izmenjenom štitastom žlezdom. Materijal i metode Ispitivanje je sprovedeno u Klinici za endokrinologiju, dijabetes i bolesti metabolizma, Kliničkog centra Srbije u Beogradu. Retrospektivno je pregledano 637 tiroidnih FNA citoloških izveštaja uzoraka, dobijenih punkcijom pacijenata sa tiroidnom nodoznom bolešću Odeljenja za štitastu žlezdu, u periodu od oktobra 2007. do januara 2010. god.
UTICAJ HRONIČNE STIMULACIJE TIREOTROPINOM NA NODOZNO IZMENJENU ŠTITASTU ŽLEZDU 53 Pacijenti su ambulantno pregledani, uzeta je anamneza i urađena laboratorijska ispitivanja (biohemija, krvna slika i hormonski status), urađen je EKG i ultrazvuk, a nekim pacijentima i scintigrafija štitaste žlezde. Nakon toga izvedena je aspiraciona punkcija tankom iglom (FNA), a dobijeni preparati analizirani u Institutu za patologiju Kliničkog centra Srbije u Beogradu. Citološki nalazi uzoraka FNA su klasifikovani pomoću sheme dijagnostičkih kategorija tiroidne FNA i to: benigno, maligno, neodređeno i neuspešno (6). Analiziran je odnos između dijagnostičkih kategorija i serumske koncentracije TSH. Podaci su statistički testirani Kruskal Wallis testom razlike pomoću kompjuterskog programa SPSS 12.0 softverskog paketa. Rezultati Ispitivan je odnos dijagnostičkih kategorija prema TSH. Svi pacijenti su na osnovu vrednosti TSH svrstani u tri kategorije, vrednosti TSH manje od normalnih (do 0,5 mu/l), normalne, referentne vrednosti TSH (0,51 4,5 mu/l) i vrednosti TSH iznad normalnih (preko 4,51 mu/l). U tabeli 1 prikazana je distribucija dijagnostičkih kategorija u odnosu na vrednost TSH. Tabela 1. Dijagnostičke kategorije zavisno od vrednosti TSH TSH <=0,5 0,51 4,5 4,51+ Ukupno Benigno N 128 392 63 583 % 22,0% 67,2% 10,8% 100,0% Maligno N 2 14 6 22 % 9,1% 63,6% 27,3% 100,0% Neodređeno N 3 23 5 31 % 9,7% 74,2% 16,1% 100,0% Neuspešno N 1 0 0 1 % 100,0% 0% 0% 100,0% Ukupno N 134 429 74 637 % 21,0% 67,3% 11,6% 100,0% Prosečna vrednost TSH u grupi benigno iznosila je 3,12±12,70 sa medijanom 1,15, prosečna vrednost TSH u grupi pacijenata sa malignom dijagnozom iznosila Dijagnostička kategorija
54 MEDICINSKI GLASNIK / str. 49-56 je 9,83±17,48 sa medijanom 3,31, dok je prosečna vrednost TSH kod pacijenata sa neodređenom dijagnozom iznosila 3,16±3,80 i medijanom 2. Analizirajući ove podatke Kruskal Wallis testom utvrđeno je da postoji statistički značajna razlika između ove četiri kategorije po grupama TSH (χ²=8,136, p=0,017). Rezultati su i grafički prikazani na grafikonu 1. Grafikon 1. Dijagnostičke kategorije zavisno od vrednosti TSH 1.0 TSH <=0.5 0.51-4.5 4.51+ 0.8 0.6 % 0.4 0.2 0.0 benigno maligno neodredjeno Kvalifikacija Diskusija TSH je poznat kao tiroidni faktor rasta, ali patogena uloga ovog hormona u tiroidnoj onkogenezi je nerazjašnjena. Rezultati pokazuju da postoji statistički značajna razlika između dijagnostičkih kategorija po grupama vrednosti TSH (χ²=8,136, p=0,017) (7). Od ukupno 637 pacijenata u našoj studiji, njih 22 (3,45%) je imalo maligni, a 31 (4,87%), koji takođe zahtevaju hirurški tretman, neodređeni citopatološki nalaz. Najviše, njih 583 (91,52%), pacijenata je bilo sa benignim nalazom, i samo jedna neuspela punkcija. Prosečna vrednost TSH u grupi pacijenata sa malignom dijagnozom iznosila je 9,83±17,48 sa medijanom 3,31. Iz dobijenih rezultata se može videti da među sve tri dijagnostičke kategorije (benigno, maligno i neodređeno) najviše je pacijenata sa referentnim vrednostima TSH, ali da postoji relativno veća proporcija (27,3%) pacijenata sa malignim citopatološkim nalazom kod grupe pacijenata sa povišenim vrednostima TSH (6 od 22 pacijenta). Dostupni navodi iz literature se slažu sa našim rezultatima.
UTICAJ HRONIČNE STIMULACIJE TIREOTROPINOM NA NODOZNO IZMENJENU ŠTITASTU ŽLEZDU 55 Na osnovu ovoga može se pretpostaviti da rizik za razvoj tiroidnog maligniteta raste kod pacijenata sa povišenim serumskim koncentracijama TSH ili sa koncentracijama TSH u gornjoj trećini referentnih vrednosti. Drugo objašnjenje bilo bi to da se kod pacijenata sa niskim koncentracijama TSH razvija autonomna funkcija, koja je u vezi sa niskim rizikom za razvoj tiroidne maligne bolesti. Naime, Fiore i sar. su analizirali vezu između serumskog TSH i dijagnoze papilarnog tiroidnog karcinoma na 10178 pacijenata sa nodoznom bolešću i našli su značajno višu koncentraciju TSH kod pacijenata sa tiroidnim karcinomom. Takođe, došli su do zaključka da je razvoj autonomne tiroidne funkcije (TSH < 0,4 μu/ml) u vezi s redukcijom rizika papilarnog tiroidnog karcinoma. Studija Ichikawa i sar. ukazala je na ekspresiju TSH receptora na ćelijskoj membrani tireocita kod benignih i malignih tumora, a Carayon i sar. da TSH povećava produkciju adenilat ciklaze, što vodi produkciji camp-a i ćelijskog rasta kroz stimulaciju ovih receptora. Kasnije je ustanovljeno da je niža incidenca karcinoma u hiperfunkcijskim nodusima u vezi sa konstitutivnim aktivišućim mutacijama TSH receptora aktivacijom camp puta preko Gsα subjedinice, dok je za karcinogenezu značajniji RAS-zavisni MAPK put preko Gβγ subjedinice i fosfatidilinozitol-3 kinaze-γ. Haymart i sar. takođe ukazuju na vezu serumskog TSH i naprednih stadijuma karcinoma, tj. ekstratiroidnog širenja karcinoma (5). Boelaert i sar. su u studiji na 1500 pacijenata pokazali da su više serumske koncentracije TSH (> 0,9 miu/l) u vezi sa rizikom za dijagnozu tiroidnog maligniteta. Najmanji rizik od maligniteta imali su pacijenti sa supkliničkom hipertireozom (TSH < 0,4 miu/l), a najveći oni sa subkliničkom hipotireozom (TSH > 5,5 miu/l). Ove rezultate su u narednim istraživanjima potvrdili i drugi autori. Haymart i sar. su ispitivali 843 pacijenta koji su zahtevali hiruršku terapiju i njihove preoperativne serumske koncentracije TSH. Verovatnoća maligniteta je bila 16% kada je TSH bio < 0,06 mu/l, 25% za TSH između 0,4 i 1,39 mu/l, 35% za TSH između 1,40 i 4,99 mu/l i 52% u grupi sa TSH preko 5 mu/l i više. Polyzos i sar. su ukazali na visoko značajnu učestalost maligniteta kada je TSH između 1,5 i 4 miu/l, tj. bliže gornjoj granici normale (5). S obzirom na to da je koncentracija TSH veća kod pacijenata sa agresivnijim tumorima, veruje se da ovaj hormon ima ulogu i u progresiji maligniteta. Nasuprot ovim činjenicama, postoji dosta argumenata protiv uloge u nastanku i progresiji tiroidnog kancera. Matsuo i sar. su pretpostavili da se kod tiroidnog karcinoma retko viđaju TSH receptorske mutacije koje su u vezi sa porastom prenosa signala. Zatim, Derwahl i sar. su u svojim in vitro studijama pokazali da su neki drugi faktori, kao što su, insulinu sličan faktor rasta IGF-1, značajni u stimulaciji rasta tiroidnog kancera, a Kimura i sar. su pretpostavili da TSH zahteva sadejstvo sa insulinom i IGF-1 ispoljio svoje proliferativno dejstvo.
56 MEDICINSKI GLASNIK / str. 49-56 Shi i sar. su utvrdili da postoji inverzni odnos između nivoa mrna TSH receptora i agresivnosti kancera. Navodi iz literature ukazuju da se tiroidni kancer često javlja u kontralateralnom lobusu u odnosu na hiperfunkcijski nodus, gde je TSH suprimovan. Brojne studije koje se bave ispitivanjem genoma pokazale su da su serumske koncentracije TSH niže kod pacijenata koji su nosioci jednog od dva alela koja su u vezi sa porastom rizika i papilarnog i folikularnog karcinoma. Zaključak Na osnovu rezultata zaključuje se da rizik za razvoj tiroidnog maligniteta raste kod pacijenata sa povišenim serumskim koncentracijama TSH. Iz tog razloga, procena rizika za razvoj maligniteta kod pacijenata sa nodozno izmenjenom štitastom žlezdom, pored kliničkih, biohemijskih parametara i nalaza FNA podrazumeva i određivanje serumske koncentracije TSH, kao pomoćnog dijagnostičkog sredstva u identifikaciji visokorizičnih pacijenata koji zahtevaju dalja ispitivanja i/ili hirurški tretman. Uloga TSH u razvoju maligniteta nije potvrđena. Ostaje nejasno da li visoke vrednosti ovog hormona uzrokuju pojavu karcinogeneze ili su, pak, posledica prisustva tiroidnog maligniteta. Literatura Cooper DS., Doherty GM., Haugen BR., et al. Management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid 2006;16:109 142. Wong CK., Wheeler MH., Thyroid nodules: rational management. World J Surg 2000; 24: 934 941. Landis SH., Murray T., Bolden S., Wingo PA., Cancer statistics. CA Cancer J Clin 1998;48:6 29. Bukhari MH., Niazi S., Hanif G. et al., An updated audit of fine needle aspiration cytology procedure of solitary thyroid nodule. Diagnostic citology 2008;36:104 112. Boelaert K., The association between serum TSH concentration and thyroid cancer. Endocrine-Related Cancer 2009;16:1065 1072. Trbojević B., Aspiracija tiroidne žlezde tankom iglom u dijagnostici tiroidnog maligniteta. Zlatibor 2002;5:37 49. Medenica S., završni akademski specijalistički rad Značaj punkcije tankom iglom u dijagnostici tiroidne nodozne bolesti, Univerzitet u Beogradu, Medicinski fakultet, Beograd, jun 2011.
THE IMPACT OF CHRONIC STIMULATION ON THYROID GLAND NODOSUM 57 Dr Sanja Medenica 1 Prof. dr Božo Trbojević THE IMPACT OF CHRONIC STIMULATION ON THYROID GLAND NODOSUM Sažetak: Uvod: Nodozna struma je klinički prepoznatljiva ograničena promena građe štitaste žlezde. FNA je prva linija dijagnostičkih testova kod uvećane štitaste žlezde. TSH je poznat kao tiroidni faktor rasta, ali patogena uloga ovog hormona u tiroidnoj onkogenezi je nerazjašnjena. Cilj: Cilj rada je da se analizira veza između povišenih vrednosti TSH i tireoidnog maligniteta kod osoba sa nodozno izmenjenom štitastom žlezdom. Materijal i metode: Retrospektivno je pregledano 637 tiroidnih FNA citoloških izveštaja uzoraka, dobijenih punkcijom pacijenata sa tiroidnom nodoznom bolešću Odeljenja za štitastu žlezdu, Klinike za endokrinologiju, dijabetes i bolesti metabolizma, Kliničkog centra Srbije u Beogradu, u periodu od oktobra 2007. do januara 2010. godine. Analiziran je odnos između dijagnostičkih kategorija citopatoloških nalaza i serumske koncentracije TSH. Podaci su statistički testirani Kruskal Wallis testom razlike pomoću kompjuterskog programa SPSS 12.0 softverskog paketa. Rezultati: Od ukupno 637 pacijenata 3,45% (22/637) je imalo maligni, a 4,87% pacijenta (31/637) neodređeni citopatološki nalaz. 91,52% (583/637) pacijenata je bilo sa benignim nalazom, i samo jedna neuspela punkcija. Prosečna vrednost TSH u grupi pacijenata sa malignom dijagnozom iznosila je 9,83±17,48 mmol/l sa medijanom 3,31 mmol/l. U sve tri dijagnostičke kategorije (benigno, maligno i neodređeno) najviše je pacijenata sa referentnim vrednostima TSH, ali postoji relativno veća proporcija, 27,3% (6/22) pacijenata, sa malignim citopatološkim nalazom 1 Dr Sanja Medenica, Božo Trbojević, The Clinic for Endocrinology, Diabetes and Diseases, of Metabolism, Clinical Centre of Serbia, Belgrade, Doktora Subotića 13, e-mail: medenicasanja@gmail.com
58 MEDICINSKI GLASNIK / str. 57-65 kod grupe pacijenata sa povišenim vrednostima TSH. Postoji statistički značajna razlika između dijagnostičkih kategorija po grupama vrednosti TSH (χ²=8,136, p=0,017). Zaključak: Zaključuje se da rizik za razvoj tiroidnog maligniteta raste kod pacijenata sa povišenim serumskim koncentracijama TSH. TSH treba koristiti kao pomoćno dijagnostičko sredstvo u identifikaciji visokorizičnih pacijenata koji zahtevaju dalja ispitivanja i/ili hirurški tretman. Ključne reči: nodozna struma, tireotropin, aspiracija tankom iglom Abstract: Introduction: Nodular goiter is a clinically recognizable restricted structure change of the thyroid gland. FNA is the first line diagnostic test for an enlarged thyroid gland. TSH is known as a thyroid growth factor, but the pathogenic role of this hormone in thyroid oncogenesis is unclear. Objective: The aim of this study is to analyze the relationship between elevated serum TSH concentrations and thyroid malignancies in patients with nodular thyroid goiter. Material and Methods: We retrospectively reviewed the 637 reports of thyroid FNA cytology of samples obtained by puncture of patients with nodular thyroid goiter, at the Department of thyroid gland, Department of Endocrinology, Diabetes and Metabolic Diseases, Clinical Center of Serbia in the period from October 2007 to January 2010. We analyzed the relationship between findings of cytopathological diagnostic categories and serum concentrations of TSH. The data were statistically tested by means of Kruskal Wallis test of differences using the computer program SPSS 12.0 software package. Results: Of total 637 patients, 3.45% (22/637) had malignant, and 4.87% patients (31/637) cytopathological indeterminate findings. 91.52% (583/637) patients were with benign findings, and only one puncture failed. The average value of TSH in the group of patients with the diagnosis of malignancy was 9.83 ± 17.48 mmol/l with a median 3.31mmol/l. In all three diagnostic categories (benign, malignant and unspecified) most patients are with the normal concentrations of serum TSH, but there is a relatively large proportion of 27.3% (6/22) of patients with malignant cytopathological findings in the group of patients with elevated TSH concentration. There is a statistically significant difference between diagnostic categories by group TSH values (χ²=8.136,p=0.017). Conclusion: It is concluded that the risk of developing thyroid malignancy increases in patients with elevated serum TSH concentrations. TSH should be used as an additional diagnostic tool in identifying high-risk patients who require further investigation and / or surgical treatment. Key words: nodular goiter, thyrotropin, fine needle aspiration
THE IMPACT OF CHRONIC STIMULATION ON THYROID GLAND NODOSUM 59 Introduction Nodular goiter is a clinically recognisable and restricted change in the structure of the thyroid gland. Nodular thyroid disease is frequent and occurs in 2-6% of cases diagnosed by palpation (5% in women and around 1% in men who live in iodine-sufficient areas), in as many as 19-35% cases in which it is diagnosed by sensitive procedures such as ultrasound and in autopsy, and in nearly 8-65% cases among general population. The prevalence increases in a linear way with age, exposure to radiation and iodine deficiency. There could also be the endemic type in the areas with iodine deficiency, when the prevalence of nodular disease in children aged 6-12 is higher than 5%, and sporadically, when the prevalence is lower than 5%. It is more common in women than in men. Thyroid nodosums can be solitary or individual, and multiple, and they can be functionally active or inactive. Solitary thyroid nodosums exist in a dimensionally and morphologically unchanged gland, whereas the dominant nodosum occurs in diffuse and multinodular goiter (1). In the absence of thyroid dysfunction, autoimmune thyroid diseases of thyreoiditis and thyroid malignancy form an entity described as a non-toxic nodular goiter. Apart from non-toxic nodular goiter, clinical forms include multinodular toxic goiter and toxic thyroid adenoma (Plummer disease). The most common causes of thyroid nodular disease are benign: colloid nodule, Hashimoto thyroiditis, plain or hemmorhagic cyst, follicular adenoma, subacute thyreoditis; and the malignant ones are: primary (originating from follicular cells papillary, follicular and anaplastic carcinoma, originating from C-cell thyreoidea medullary thyroid carcinoma, and lymphoma) and secondary metastatic carcinoma. Clinical importance of the thyroid nodular disease apart from the aesthetic changes such as thickening of the neck, local compressive syndromes and thyroid dysfunction is the possibility of malignancy development in 5% of cases. Annual incidence of thyroid carcinoma is 1-2 per 100,000 people, which makes 90% of all malignancies of the endocrinological system, 1% of all malignancies in people and 0.5% of morbidity caused by malignancy (2,3). Relevant anamnestic and clinical data which indicate a potential malignant nature of the nodule are: family anamnesis of thyroid carcinoma, previous radiation of the head and the neck and/or the whole body, rapid growth of the nodule, hard and solid nodule, hoarseness or vocal cord paralysis, ipsilateral cervical lymphadenopathia and fixation of the nodule to the surrounding tissue. The disease is diagnosed on the basis of physical examination, laboratory analyses, fine needle aspiration (FNA) and visualisation method (scyntygraphy, ultrasound and ultrasound elastography, CT, MR and PET). Since many clinical findings in the solitary nodule do not make a distinction between a benign and a malignant process, more efficient methods are needed for the selection of patients who should have surgery. The number and range of operations are reduced in this way. Fine needle aspiration (FNA) was applied for the first time by Martin and Ellis at the Memorial Hospital for Cancer and Allied Diseases in New York in 1930, although, due to its restrictions, it was rarely used, only to become popular
60 MEDICINSKI GLASNIK / str. 57-65 in the last four decades when, in Scandinavia, it was introduced as one of the primary diagnostic tests in thyroid nodular disease (4). It is the main method of preoperative diagnosis in children and adults. It is superior to clinical, radionuclide and ultrasound methods. In the last few years, it has proved itself as the key diagnostic procedure and it has drastically changed the approach in thyroid nodular disease treatment. It is among the primary diagnostic tests in cases of an enlarged thyroid. FNA application reduces the number of throidectomies by 50% and total medical expanses of over 25% of patients. The key to the success of this method is an adequate and representative cell sample and expertise in thyroid cytology. Classification of diagnostic categories of the thyroid FNA usually involves the following categories: malignant, benign, indeterminate and unsuccessful. The term indeterminate refers to lesions which could not be definitely categorised as benign or malignant on the basis of their cytological picture, and they include follicular, oxyphyllic lesions (Hurthle cell) and suspicious findings. The category of unsuccessful refers to the samples which do not provide sufficent material or the material is not adequate for a diagnosis. The therapy is usually surgery or radioiodine ablation, whereas recently, in the cases indicated for them, recombinant human thyreotropin therapy, percutaneous ethanol injection, laser thermal ablation and radiofrequency ablation have been used. Thyreotropin (TSH) is a hormone of the frontal lobe of the hypofise which causes an increased secretion of the thyroid gland hormones. It is also known as the factor of growth of thyroid nodules. The suppression of TSH by exogenous hormones of the thyroid prevents the further enlargement of the existing nodules and the development of the new ones. The suppressive thyroxin therapy shows positive effects in patients with differentiated thyroid carcinoma. It is well-known that chronic iodine deficiency, which causes a decrease in the serum concentrations of thyroid hormones with a consequential increase in concentrations of TS, is a factor of goiter development and follicular thyroid carcinoma. Considering all of the above-mentioned facts, it is believed that TSH serum concentration is an independent indicator of thyroid malignancy in patients with a nodular thyroid. It is assumed that chronic thyreotropin stimulation of the nodular thyroid causes neoplasia and carcinogenesis. Given that TSH concentration is higher in patients with aggressive tumors, it is believed that this hormone also causes tumor progression. Consequently, patients with higher TSH concentrations need to be examined more elaborately and treated more aggressively. Study objective Study objective is to analyse the relationship between increased TSH values and thyroid malignancy in people with nodullary thyroid.
THE IMPACT OF CHRONIC STIMULATION ON THYROID GLAND NODOSUM 61 Material and methods The study was conducted at the Clinic for endocrinology, diabetes and metabolism diseases, Clinical Centre of Serbia, Belgrade. Retrospectively, 637 thyroid FNA cytology report samples were examined, obtained by performing puncture inpatients with nodular thyroid disease at the Thyroid Department in the period from October 2007 to January 2010. The patients were examined at the dispensary, anamnesis was taken as well as all the laboratory anayses (biochemistry, blood sample and hormone status), ECG and ultrasound were made, and thyroid scintigraphy was done in some patients. Afterwards, fine needle aspiration puncture (FNA) was performed, and the obtained results were analysed at the Institute for pathology at the Clinical Centre of Serbia in Belgrade. Cytological findings of the FNA samples were classified according to the scheme of diagnostic categories of thyroid FNA as: benign, malignant, indeterminate and unsuccessful (6). The relationship between diagnostic categories and TSH serum concentrations was analysed. The data were statistically tested by means of Kruskal Wallis test of differences using the computer program SPSS 12.0 software package. Results The relationship between diagnostic categories and TSH was analysed. All the patients were divided into three categories on the basis of TSH values: TSH values lower than (up 0.5 mu/l), normal, referential TSH values (0.51-4.5 mu/l) and TSH values above the normal range (over 4.51 mu/l). Table 1. shows the distribution of diagnostic categories in relation to TSH values. Table 1. Diagnostic categories in relation to TSH values TSH <=0.5 0.51-4.5 4.51+ Total Diagnostic category Benign Malignant Indeterminate Unsuccessful Total N 128 392 63 583 % 22.0% 67.2% 10.8% 100.0% N 2 14 6 22 % 9.1% 63.6% 27.3% 100.0% N 3 23 5 31 % 9.7% 74.2% 16.1% 100.0% N 1 0 0 1 % 100.0%.0%.0% 100.0% N 134 429 74 637 % 21.0% 67.3% 11.6% 100.0%
% 62 MEDICINSKI GLASNIK / str. 57-65 The average TSH value in the benign group was 3.12±12.70 with the median of 1.15, the average TSH value in the group of patients with the diagnosis of malignancy was 9.83±17.48 with the median of 3.31, whereas the average TSH value in patients with indeterminate diagnosis was 3.16±3.80 with the median of 2. Analysing these data by means of Kruskal Wallis test, it was established that there was a statistically relevant difference between these four categories within TSH groups (χ²=8.136, p=0.017). The results are shown in Graph 1. Graph 1. Diagnostic categories in relation to TSH values 1.0 TSH <=0.5 0.51-4.5 4.51+ 0.8 0.6 % 0.4 0.2 0.0 benigno malignant maligno neodredjeno indeterminate Kvalifikacija Qualification Discussion TSH is known as the thyroid growth factor, but the pathogenous role of this hormone in thyroid oncogenesis is still unresolved. The results show that there is a statistically relevant difference between diagnostic categories in terms of group TSH values (χ²=8.136, p=0.017) (7). Of the total 637 patients in our study, 22 (3.45%) of them had malignant, and 31 (4.87%) of them had indeterminate cytopathological findings, which also called for a surgical treatment. The largest number of them, 583 (91.52%) patients had benign findings and only one puncture failed. The average TSH value in the group of patients with the malignant diagnosis was 9.83±17.48 with the median of 3.31. The obtained results show that in all three diagnostic categories (benign, malignant and indeterminate), the largest
THE IMPACT OF CHRONIC STIMULATION ON THYROID GLAND NODOSUM 63 number of patients are with referential TSH values, but there is a relatively larger proportion (27.3%) of patients with malignant cytopathological findings in the group of patients with higher TSH values (6 out of 22 patients). Available citations from literature concord with our results. On the basis of this, it can be concluded that the risk of the development of thyroid malignancy is higher in patients with increased TSH serum concentrations or with TSH concentrations in the upper part of referential values. The second explanation might be that in patients with low TSH concentrations, an autonomous function is developed, which is connected with the low risk of developing thyroid malignancy. Namely, Fiore and associates analysed the connection between serim TSH and the diagnosis of papillary thyroid carcinoma in 10,178 patients with a nodular disease and found out that patients with thyroid carcinoma had a much higher concentration of TSH. At the same time, they came to the conclusion that the development of the autonomous thyroid function (TSH < 0.4 μu/ml) was related to the reduction in the risk of developing papillary thyroid carcinoma. The study of Ichikawa and associates showed the expression of TSH receptors at the cell membrane of benign and malignant tumors, and Carayan and associates concluded that TSH increased the production of adenylate cyclase, which lead to the camp production and cell growth through the stimulation of these receptors. It was later established that the lower incidence of carcinoma in hyperfunctional nodules was related to the constituent activating mutations of TSH receptors by activating camp pathway via Gsα subunit, whereas RAS-dependent MAPK pathway activated via Gβγ subunit and phosphatidylinositol-3 kinase were more important for carcinogenesis. Haymart and associates also showed the connection between the serum TSH and advanced stages of carcinoma, i.e. extrathyroid spread of carcinoma (5). In the study involving 1,500 patients, Boelaert and associates showed that higher TSH serum concentrations (> 0.9 miu/l) were related to the risk of a thyroid malignancy diagnosis. The lowest risk of malignancy existed in patients with subclinical hyperthyreosis (TSH < 0.4 miu/l), and the highest was in patients with subclinical hyperthyreosis (TSH > 5.5 miu/l). These results were later confirmed by other authors in their research. Haymart and associates examined 843 patients who needed surgery and their preoperative TSH serum concentrations. Malignancy probability was 16% when TSH was < 0.06 mu/l, 25% for TSH between 0.4 and 1.39 mu/l, 35% for TSH between 1.40 and 4.99 mu/l and 52% in the group with TSH over 5 mu/l and more. Polyzos and associates pointed at the high frequency of malignancy when TSH was between 1.5 and 4 miu/l, i.e. when it was near the upper limit of the normal range (5). Given that TSH concentration is higher in patients with more aggressive tumors, it is believed that this hormone also affects malignancy progression. Contrary to these facts, there is a large number of arguments against its role in the development and progression of thyroid cancer.
64 MEDICINSKI GLASNIK / str. 57-65 Matsuo and associates suggested that in thyroid carcinoma TSH receptor mutations related to the increase in signal transport were very rare. Then, in their vitro studies, Derwahl and associates showed that some other factors, such as insulin-like growth factor IGF-1, were important in the stimulation of growth of thyroid cancer, and Kimura and associates suggested that TSH needed to act together with insulin and IGF-1 in order to show its proliferative effects. Shi and associates established that there was an inversive relationship between the level of mrna TSH receptors and cancer aggressiveness. Citations from literature confirm that thyroid cancer very often appears in contralateral lobe in relation to hyperfunctional nodule, where TSH is supremed. Numerous studies dealing with the genome showed that serum TSH concentrations were lower in patients who carried one or two alleles related to the increase in the risk of developing papillary and follicular carcinoma. Conclusion On the basis of the results, it is concluded that the risk of developing thyroid malignancy is higher in patients with increased TSH serum concentrations. Consequently, the assessment of risk of developing malignancy in patients with a nodular thyroid, apart from clinical, biochemical parameters and FNA findings, demands the determination of TSH serum concentration as an auxiliary tool in the identification of high-risk patients who need further examination and/or surgery. The role of TSH in malignancy development has not been confirmed. It is still unclear whether high values of this hormone cause carcinogenesis or whether they are the consequence of thyroid malignancy. Literature Cooper DS, Doherty GM, Haugen BR, et al. Management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid 2006; 16:109 142. Wong CK, Wheeler MH, 2000 Thyroid nodules: rational management. World J Surg 24: 934 941. Landis SH, Murray T, Bolden S, Wingo PA, 1998 Cancer statistics. CA Cancer J Clin 1998; 48:6 29. Bukhari MH, Niazi S, Hanif G et al. An updated audit of fine needle aspiration cytology procedure of solitary thyroid nodule. Diagnostic citology 2008; 36:104 112. Boelaert K. The association between serum TSH concentration and thyroid cancer. Endocrine- Related Cancer 2009; 16:1065 1072. Trbojević B.:Fine needle aspiration of thyroid gland in the diagnostics of thyroid malignancy. Zlatibor 2002; 5:37 49.
THE IMPACT OF CHRONIC STIMULATION ON THYROID GLAND NODOSUM 65 Medenica S., final academic specialist study The importance of fine needle aspiration in the diagnostics of nodular thyroid disease, University of Belgrade, Faculty of medicine, Belgrade, June 2011.