Role of PET CT Scan in Redefining Treatment of Incidental Gall Bladder Carcinoma

Introduction: Incidental diagnosis of gall bladder cancer is increasing. The role of PET-CT in modifying the extent of surgery and adjuvant treatment is still unclear. We have evaluated the same in this study. Methods: This is a prospective audit of gall bladder cancer from Tata Memorial Hospital, Mumbai, India. Patients found non-metastatic on initial imaging underwent laparotomy for revision surgery. Results: One hundred and eight patients had a PET-CT scan done before revision surgery. Median duration of PET-CT from primary surgery was 42 days. PET scan of 64 (59.3%) patients had no uptake in body (N-PET). Rest had loco-regional uptake (L-PET). N-PET patients had lesser residual disease than L-PET patients (23% vs. 52%; P = 0.004). N-PET pT1b patients had no residual disease as compared to L-PET patients (0% vs. 33%, P = 0.028). pT1b patients did not have residual disease in liver wedge irrespective of PET status. Majority of the recurrences were distant and happened in pT2 patients. RFS was longer in N-PET than L-PET patients (P = 0.09) and in pT1b patients than pT2 and pT3 (P = 0.006). OS was longer in pT1b patients than pT2 patients (P = 0.038). Conclusions: PET-CT scan is useful to stratify patients with incidentally diagnosed gall bladder cancer for effective treatment. Liver wedge resection may be avoided in all pT1b patients. PET negative pT1b patients may be observed as chance of relapse is low. There may be a role for giving chemotherapy to all pT2 patients as they have high chance of recurrence and nodal metastases. (C) 2016 Wiley Periodicals, Inc.