Clinical, Pathologic and Molecular Updates

Transcription

1 Colorectal Cancer: Clinical, Pathologic and Molecular Updates Joanna A. Gibson, M.D./Ph.D. Yale University School of Medicine/Yale New Haven Hospital, Department of Pathology Gastrointestinal, Pancreaticobiliary and Liver Pathology Service, Tumor Profiling Service New Haven, Connecticut S L I D E 1

2 Tough Mudder obstacle demonstrates difficulty of Update subject matter Update #1 Rising incidence of colorectal cancer in young patients Climbing over hay bales S L I D E 2

3 Background: CRC incidence Overall CRC rates in the US have been declining at 3% annually Reduction of CRC risk 1975 to 2000 is attributed equally to changes in the prevalence of risk factors and the uptake of screening Recent steep decline is primarily driven by screening Risk of reduction of rectal cancer > colon cancer S L I D E 3

4 Rising incidence in young patients Colon cancer incidence rates increased by 1.0%-2.4% annually since the mid-1980s in adults age 20 to 39 years 0.5%-1.3% since the mid-1990s in adults age 40 to 54 years Rectal cancer incidence rates have been increasing longer and faster 3.2% annually from in adults age years S L I D E 4

5 Colorectal cancer in young patients Increased rate potentially attributed to: Obesity, unhealthy diet (red meat, lack of vegetables) and lack of exercise Increasing incidence among young patients is concerning Current screening protocols (in patients >50 years) are inadequate to detect colon cancer in younger patients People younger than 55 are 58% more likely to be diagnosed with latestage disease than older people Death rate for colorectal cancer in adults ages increased by 1% each year from 2004 to 2014 Previously, mid-1970s through the 1990s, death rate had been decreasing by almost 2% each year S L I D E 5

6 The ACS recommends that adults aged 45 years and older with an average risk of colorectal cancer undergo regular screening with either a high-sensitivity stool-based test or a structural (visual) examination, depending on patient preference and test availability. As a part of the screening process, all positive results on noncolonoscopy screening tests should be followed up with timely colonoscopy. The recommendation to begin screening at age 45 years is a qualified recommendation. The recommendation for regular screening in adults aged 50 years and older is a strong recommendation S L I D E 6

7 Carrying a log Update #2 Colorectal cancer 8 th Edition AJCC staging S L I D E 7

8 Summary of staging updates in 8 th edition of AJCC pt ptx primary tumor cannot be assessed pt0 no evidence of primary tumor ptis intramucosal carcinoma pt1 invasion into submucosa pt2 invasion into muscularis propria pt3 invasion through muscularis propria pt4 invasion into visceral peritoneum (pt4a) or adjacent structures (pt4b) pn pnx cannot be assessed pn0 no regional node metastases pn0(i+) metastases <0.2 mm pn1a one metastasis > 0.2 mm pn1b 2-3 metastases pn1c non-nodal tumor deposits without identified LN metastases pn2a 4 6 metastases pn2b 7 or more metastases pm or cm Note that there is no pmx; not valid M0 No distant metastases by imaging (not assigned by pathologist) M1 Metastasis to one or more distant site M1a metastasis to one site/organ without peritoneal involvement M1b metastases to two or more sites/organs without peritoneal involvement M1c peritoneal involvement regardless of other organ involvement S L I D E 8

9 Staging updates in 8th edition of AJCC: T category Classification of Tis been clarified : High grade dysplasia (HGD) is no longer considered Tis HGD = intraepithelial carcinoma (rarely used diagnosis of colorectal neoplasia), not specifically defined by AJCC Cytologic and architectural features: high N:C ratio, nuclear pleomorphism, loss of nuclear polarity and intraluminal cribriforming in at least two (or more) glands HGD should not be assigned to the Tis category, ie, HGD = T0 No risk for lymph node spread S L I D E 9

10 Staging updates in 8th edition of AJCC: T category Tis refers to intramucosal carcinoma (IMC): invasion into lamina propria and also invasion into but not through the muscularis mucosae Invasion not specifically defined in AJCC, but others have defined IMC as: diffuse cribriforming (most common), back-to-back glands, or single cell invasion (least common) Why is it still called in situ if there is invasion? Negligible risk for metastasis S L I D E 10

11 Staging updates in 8th edition of AJCC: T category Problem: Distinguishing HGD from IMC is notoriously subjective with high interobserver variability HGD or IMC? T0 or Tis? Patient gets a diagnosis of carcinoma or not Management is the same S L I D E 11

12 Staging updates in 8th edition of AJCC: N category pn1c: discreet tumor nodules within the lymph drainage of the primary carcinoma without identifiable lymph node and without vascular or neural structure Subserosa Mesentery Nonperitonealized pericolic or perirectal/mesorectal tissues Perineural, lymphatic or vascular invasion should not be recorded as N1c pn0(i+): Isolated tumor cells or small cluster <0.2 mm are usually incidentally found in patients who have otherwise negative lymph nodes; consider levels to ensure correct classification Deposits 0.2 mm-2.0 mm have been referred to as micrometastasis, pn1mi S L I D E 12

13 Staging updates in 8th edition of AJCC: T category pt4a was clarified : Involvement of the serosal surface (invasion into visceral peritoneum) Tumors with perforation in which the tumor cells are continuous with the serosal surface through inflammation Significance of tumors at <1 mm from the serosal surface and accompanied by serosal reaction is unclear Some studies show a high risk for peritoneal relapse, some don t T4a T3 T4a S L I D E 13

14 Staging updates in 8th edition of AJCC: M category pm1a: mets to single site, excluding peritoneal carcinomatosis Multiple mets in one organ only, even if paired (lung, ovary) is still M1a pm1b: mets to multiple sites/solid organs, excluding peritoneal carcinomatosis New Category of pm1c: Peritoneal carcinomatosis with or without blood borne metastases to visceral organs Occurs in 1-4% of patients Prognosis is worse than mets to visceral organ(s) S L I D E 14

15 Waist deep in mud Update #3 Molecular Tests in Clinical Use for Colorectal Cancer S L I D E 15

16 Molecular testing in CRC AJCC level of evidence 1 Microsatellite instability* Ras mutations BRAF mutation Hereditary Lynch syndrome, FAP, Hamartomatous polyposes CIN MSS KRAS APC P53 Smad4 Ultramutated POLE Serrated Pathway MSI-H CIMP dmmr BRAF Chart adapted from Müller, Ibrahim and Arends. Molecular pathological classification of colorectal cancer. Virchows Arch *Discussed at a prior GUT-C S L I D E 16

17 Driver mutations in CRC TGF-β EGFR APC ~80% APC Altered WNT signaling β-catenin Axin1 Axin2 β-catenin SMAD4 ~10% Altered TGF-β signaling Smad3 Smad4 Smad2 p p KRAS 40-45% NRAS ~3% BRAF ~10-15% MEK Rare RAS RAF MEK MAPK p p p p SOS Grb-2 p p Altered EGFR signaling PIK3CA 15% PI3K AKT1 5% AKT mtor PTEN 10-20% PTEN β-catenin β-catenin Smad4 MAPK p PMS2 MSH6 Altered MMR MLH1 MSH2 Mutation Altered Expression of Target Genes Proliferation Survival Apoptosis S L I D E 17

18 BRAF Serine Threonine Kinase >80% mutations = p.v600e (c.1799t>a) Leads to constitutive activation of kinase activity Mutually exclusive with RAS mutations COSMIC database BRAF mutation hotspot V600E Also, the same BRAF V600E mutations is commonly seen in papillary thyroid cancer, melanoma, NSCLC, hairy cell leukemia S L I D E 18

19 KRAS and NRAS Small GTPases Activating mutations cause Ras to accumulate in the active GTP bound state by impairing intrinsic GTPase activity ~30% of CRC have KRAS mutations in exon 2 (codons 12 or 13) ~15% CRC have KRAS mutations in exons 3 or 4 ~3% of CRC have NRAS mutations in exon 2, 3 or 4 COSMIC database KRAS mutation hotspots NRAS mutation hotspots S L I D E 19

20 Molecular Testing in CRC Molecular Diagnostics Lab (dir. Dr. Hui) Tumor Profiling Lab (dir. Dr. Walther) Simple/older tech PCR followed by SSCP TagMan (quantitative PCR) Complex/new tech Next Generation Sequencing Require more DNA, longer turn around Require less DNA, faster turn around BRAF V600E KRAS codons 12 &13 KRAS 14 mutations in codons 12, 13 & Gene Hotspot panel Oncomine panel 1 mutation 2 mutations 33 mutations in 6 genes 2800 mutations in 50 genes If KRAS is WT, reflex to NRAS (17 mut) BRAF (4 mut) PIK3CA (12 mut) AKT (1 mut) MEK1 (1 mut) 161 genes; 51 fusions & 43 amplifications???? mutations S L I D E 20

21 50 gene panel Cancer Hotspot* Panel ABL1 EGFR GNAS KRAS PTPN11 AKT1 ERBB2 GNAQ MET RB1 ALK ERBB4 HNF1A MLH1 RET APC EZH2 HRAS MPL SMAD4 ATM FBXW7 IDH1 NOTCH1 SMARCB1 BRAF FGFR1 JAK2 NPM1 SMO CDH1 FGFR2 JAK3 NRAS SRC CDKN2A FGFR3 IDH2 PDGFRA STK11 CSF1R FLT3 KDR PIK3CA TP53 CTNNB1 GNA11 KIT PTEN VHL *Genes are sequenced at predetermined mutational hotspot regions only (blue = TaqMan mutation assays also available; TaqMan requires less DNA) Patients with stage IV disease/metastatic CRC or any patients who may receive anti-egf therapy Determines Ras/Raf status to determine if anti EGFR therapy is appropriate Identification other driver mutations that may be therapeutically targetable (Ion AmpliSeq Cancer Hotspot Panel v2) S L I D E 21

22 Oncomine Tumor Profiling Panel* =87 =48 =43 =51 *Requires Germline control Patients with stage IV disease/metastatic CRC or patients who have failed conventional therapy Identification driver mutations that may be therapeutically targetable S L I D E 22

23 Summary of KRAS, NRAS, and BRAF Mutation Testing Utility Labs must use validated CRC biomarker testing methods with sufficient performance characteristics for the intended clinical use Rec #1: All patients with metastatic CRC should have tumor tissue genotyped for RAS and BRAF mutations Rec #2: Patients with any known KRAS mutation (exon 2, 3, 4) or NRAS mutation (exon 2, 3, 4) should not be treated with anti-egfr agents (cetuximab or panitumumab) Rec #3: BRAF V600E mutation makes response to anti-egfr treatment (with panitumumab or cetuximab) highly unlikely (unless given with a BRAF inhibitor) Rec #4: BRAF V600E in MSS CRC confers a worse prognosis Rare ~4% of CRC Rec #5: BRAF V600E should be tested in MMR deficient CRC with loss of MLH1/PMS2 for possible Lynch syndrome Presence of BRAF V600E strongly favors a sporadic pathogenesis Absence of BRAF V600E does not exclude risk of Lynch syndrome 1. Sepulveda AR et al. Molecular Biomarkers for the Evaluation of Colorectal Cancer: Guideline Summary From the American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and American Society of Clinical OncologyJ Oncol Pract. (2017) Am J Clin Pathol. (2017) J Mol Diagn. (2017) 2. Benson AB et al. NCCN Guidelines Insights: Colon Cancer, Version J Natl Compr Canc Netw. (2018) S L I D E 23

24 Summary: Molecular Tests in Clinical Use for Colorectal Cancer at YNHH Test Method(s) Patient Clinical Application MSI IHC and/or PCR Universal Screening for Lynch Syndrome Good prognosis Lack of response to 5-FU Response to PD1 inhibition BRAF MLH1 promoter methylation KRAS mutation Expanded Ras panel 50 Gene Hot Spot Panel PCR/Sanger sequencing/sscp Methylation specific quantitative PCR PCR/Sanger sequencing/sscp Quantitative PCR (TaqMan) To exclude Lynch syndrome in patients who have MLH1/PMS2 loss Stage IV/metastatic CRC To exclude Lynch syndrome in patients who have MLH1/PMS2 loss V600E mutation correlates with sporadic MSI-H CRC and excludes Lynch Syndrome V600E mutation has worse prognosis in MSS cancer V600C mutation has lack of response to anti EGFR therapy MLH1 promoter methylation correlates with sporadic MSI-H CRC and excludes Lynch Syndrome Stage IV/metastatic CRC Wild type KRAS predicts sensitivity to anti-egfr therapy (cetuximab/panitimumab) If KRAS WT, reflex to AKT1, BRAF, MEK1, NRAS, PIK3CA Phasing out in favor of 50 GP NGS Stage IV/metastatic CRC 50 gene panel targeted to gene hot spots (2800 mutations); predominantly used in Stage IV disease to determine Ras/Raf status and/or other drivers Oncomine NGS Oncologist Request/Stage IV/metastatic CRC/failed conventional therapy/clinical trial 161 genes (87 hotspot/48 full length) & 51 fusions & 43 amplifications; predominantly used in advanced Stage IV disease/clinical trial to identify targets S L I D E 24

25 Just jump! The End S L I D E 25