Long-Term Outcome of Conversion Surgery for Initially Unresectable Pancreatic Cancer: A Single Institutional Experience

Introduction: Owing to recent advances in chemotherapy and radiation therapy, it is under a debate whether surgical resection, so-called conversion surgery (CS), would further prolong survival for those with UR-PDACs. Method: A retrospective analysis was performed using all PDACs during 2010/6-16/12. CS is considered if a long-term good response and significant reduction of tumor markers were obtained. Outcomes were compared between patients who underwent CS (Group A) with those without surgery (Group B). Group B was further subdivided into two groups, “responder” defined by those whose disease was controlled at least for 6 months but not underwent surgery (B1) and “non-responder” (B2). Result: 58 locally-advanced (UR-LA) and 65 metastatic (UR-M) PDACs, were included. Of those, 13 UR-LAs (22%) and 3 UR-Ms (4.6%), were operated with a median time to surgery of 8.5 months. Surgical procedures included combined resections of artery (63%), portal vein (56%), and other organs (50%). R0 resection was achieved in all patients, nodal involvement was in 31%. Histologic antitumor effect evaluated by the Evans grade included 50% with IIB and 25% with III. Overall survival was significantly better in Group A than B1 and B2 (p<0.001), with an estimated 3- and 5-year survival rate of 66% and 55.2%. After a median follow-up of 40 months, 10 out of 16 patients who underwent CS are still alive. Multivariate analysis showed that mGPS of zero (HR=3.4) and RECIST SD or better (HR=6.1) at 6 months after the initial treatment in addition to CS (HR=3.91) were identified as independent prognostic factors, although none of the pre-treatment factors were significant. Conclusion: In our experience, CS showed beneficial for patients with UR-PDAC as an option in multidisciplinary treatment. CS should be considered if obtained longer response (RECIST≥SD) with maintaining good physical condition (mGPS=0) at 6 months after the initial treatment.