Esophageal Cancer What is the value of performing PET scan routinely for staging of esophageal cancers What is the sensitivity and specificity of PET scan for metastatic lesions When should PET scan be performed during the work-up for maximum benefit
Lymph node staging Size limitation 5-7 mm Description of local nodes being more difficult for PET to detect due to adjacent tumor FDG activity Meta-analysis (n=490) showed the sensitivity and specificity of detecting lymph node metastasis as 51% and 84% respectively. Clin Oncol 2004;22(18):3805-12
Lymph node staging 1. Studies evaluating PET in initial st aging of esop hageal adenocarcinoma Study Institute Design N Other Modalities AC/SCC (%) T (%) * Block 1997 30 Wash U Unclear 58 CT 59 / 40 Ń Ń Ń Ń Ń 15 Luketic h 1997 31 Pitt Retro 35 EUS, bscan, 71 / 26 97 45 100 88 93 20 CT, Ls or Ts Low e 2005 3 Mayo Prosp 75 CT, EUS 90 / 10 Ń 82 60 81 91 4 Flamen Gathuisber 2000 4 gbelgium Prosp 74 CT, EUS 72 / 28 95 39 97 74 90 Ń Meyers ACOSO 2007 6 G Heeren Groningen, 2004 10 Netherland s Sens (%) Prosp 189 CT NR 91 Ń Ń N Spec (%) Sens (%) M Spec (%) PCM (%) -10% upstaged to M1b falsely upstaged to M1b Prosp 74 CT, EUS 84 / 16 95 55 71 78 98 7 Mayo Study: EUS operator opened a sealed envelope to learn if PET and CT had identified additional nodes or metastatic foci that could be assessed. If so, the operator sampled these areas, thus allowing histopathologic evaluation of all detected nodes in all modalities.
Distant Metastasis In the meta-analysis, patient management is changed in 3-20% of cases with preoperative PET Clin Oncol 2004;22(18):3805-12 For any M1 disease PET finds 6-15% more patients with metastatic disease Distant metastasis (M1b) are found in patients with negative CT in 5-7% of cases. The Journal of thoracic and cardiovascular surgery 2007;133(3):738-45. J Nucl Med 2004;45(6):980-7.
Optimal Performance of PET PET findings need to be pathologically confirmed in most cases Even with negative CT, PET can discover other metastatic sites and should be preformed pretherapy As such, performing PET prior to CT allows for potential bx of PET positive findings at the time of CT or EUS
Optimal Performance of PET The contributions of PET, EUS and CT are complimentary, each finding disease that can be missed by the other Mol Imaging Biol 2005;7(6):422-30
Esophageal Cancer Does FDG-PET help in Assessing response during treatment restaging post Chemo-XRT for further management What is the ideal time for restaging PET
Assessing Response PET during therapy has shown the ability to predict responders with better survival. J Clin Oncol 2006;24(29):4692-8. Data has shown that when nonresponders have chemorads stoped and surgery performed (MUNICON) survival is similar The overall survival of nonresponders (26 months), who were denied further chemotherapy, did not appear to be lower than historical controls who received chemotherapy and surgery (15-18 months)
Assessing Response After completion of neoadjuvant chemo and RT, PET has been unable to define primary tumor complete response accurately as either microscopic disease or reaction to treatment causing falsely elevated FDG are confounders. J Thorac Oncol 2006;1(5):478-86. PET can find newly developed sites of metastasis in the followup scan in 2-5% of patients. Journal of thoracic and cardiovascular surgery 2005;129(6):1232-41.
Assessing Response Most compelling use for PET is to detect additional sites of metastasis prior to surgery. In such cases, PET should be performed just prior to surgery. Using PET for directing treatment alterations is still likely premature as a practice recommendation.
Gastric Cancer What is the value of PET scan in patients with gastric cancer Should it routinely be used in its management
Gastric Cancer Gastric cancer can have much less FDG uptake than other tumors Up to 25 % of primary tumors may not be FDG avid Awareness of poor sensitivity for metastasis in such cases is key If the tumor is avid the data is as supportive as for esophageal cancer
FDG AVID NON FDG AVID
Rectal Cancer Is there a role for PET scan in staging and management of rectal cancers
Staging Rectal Cancer 88 patients with rectal cancer studied prospectively Prospective recording of stage and management plan prior to and after PET PET findings changed stage in 31% 14% (12) upstaged (7N, 4 M, 1Nand M) 17% (14) downwstaged(10n, 3M, 1 Nand M) Management changed in 10 patients (12%) Dis Colon Rectum 2008 51: 997-1003
Response Assessment, Rectal Sensitivity and specificity in identifying response : 100% (CT 54%, MRI 71%) and 60% (CT 80%, MRT 67%). Positive and negative predictive values: 77% (CT 78%, MRI 83%) and 100% (CT 57%, MRI 50%) (PET P=0.002, CT P=0.197, MRI P=0.500). (n=23) Eur Radiol 2005 15:1658-66 PET predicts responders to neoadjuvant chemoradiation (n=45). Eur J Nucl Med Mol Imaging 2007 34:1583-93 Assessment for new metastatic disease prior to therapy may also be efficacious
Colon Cancer Is there a role for routine PET scan in staging of colon cancer
Lymph Node Staging Colorectal Prospective evaluation of staging with PET prior to surgery The sensitivity, specificity and accuracy of diagnosis in lymph nodes based on SUV were: 51.2, 85.1 and 69.3% in the proximal sites and 62.5, 92.5 and 89.7%, respectively, in the distant site. Colorectal Jpn J Clin Oncol 2008 38:347-53
Staging Colon Sensitivity for: PET CT Intraluminal CA 100 % 37% Lymph Nodes 29 % 29% Liver Metastasis 88% 38% Radiology 1998;206:755-760
Staging Colon Prospective trial of 102 colorectal cancer patients FDG-PET findings were important, revealing unknown disease in 19.2%, changing the staging in 13.46% and modifying the scope of surgery in 11.54% Eur J Nucl Med Mol Imaging 2007 34:859-67
Staging Colorectal Potential cost savings resulting from demonstration of non resectable tumor by PET were calculated at $3003 per preoperative study. Arch Surg 1999;134:503-511
Monitoring Response Successfully determines response to chemo therapy, local ablative therapy, preoperative radiotherapy and multimodality therapy. Review of response data J Nucl Med 200950:43s-54s
Val Lowe/Elliot Fishman In follow up of these patient, is there a role for CT scan or PET scan or PET/CT
Colon/Rectal/Anal Surveillance National Cancer Center Network 2009 recommendations for follow-up Consider PET in surveillance first line after CEA elevation (repeat in 3 months if negative) Consider PET after other negative exams, colonoscopy, CT etc. with CEA elevation PET/CT after discovery of a potentially resectable new metastasis.
GIST What is the role of PET scans in management of patients with a GIST? Staging Evaluation of response to treatment
Staging GIST PET/CT can miss up to 1/3 of GIST metastasis due to poor uptake or confusion with bowel Journal of Nuclear Medicine Vol. 45 No. 3 357-365 Other authors have shown equivalency in staging but not superiority over CT Utilization of the CT component of the PET/CT is important
GIST Response 16 patients treated with imatinib PET after 1 week of treatment 11/16 with a reduction of 65% in SUV, responders 5/16 reduction of 16% in SUV, nonresponders PFS best determined by PET (p=0.002) vs CT Nuc Med Commun 2004 25;433-8
GIST Response 23 patients treated with sunitinib after imatinib failure. Progression free survival correlated with post 4 wk treatment PET (p,0.0001). Multivariate analysis showed shorter PRS in patients with higher SUV None of the patients with elevated FDG subsequently responded. JCO 2009 27; 439-45
PET: Shows a complete response. Before and after 5 days of Gleevic therapy.
Pancreas Cancer What is the role of PET scans in staging of pancreatic cancer staging Are there any caveats to its use
Staging and Diagnosis Diagnosis Staging 7 studies; 368 pts 6 studies; 360 pts Sens Spec Sens Spec PET 83% 82% 94% 90% CT 65% 61% 82% 75%
Staging Pancreatic Cancer PET/CT is best used when CT is equivocal The absolute uptake of FDG is on the lower range of uptake in all cancer