Role of adjuvant surgery for patients with initially unresectable pancreatic cancer with a long-term favorable response to non-surgical anti-cancer treatments: Results of a project study for pancreatic surgery by the Japanese Society of Hepato-Biliary-Pancreatic Surgery

Purpose: A multicenter survey was conducted to explore the role of adjuvant surgery for initially unresectable pancreatic cancer with a long-term favorable response to non-surgical cancer treatments. Methods: Clinical data including overall survival were retrospectively compared between 58 initially unresectable pancreatic cancer patients who underwent adjuvant surgery with a favorable response to non-surgical cancer treatments over 6 months after the initial treatment and 101 patients who did not undergo adjuvant surgery because of either unchanged unresectability, a poor performance status, and/or the patients' or surgeons' wishes. Results: Overall mortality and morbidity were 1.7 and 47 % in the adjuvant surgery group. The survival curve in the adjuvant surgery group was significantly better than in the control group (p < 0.0001). The propensity score analysis revealed that adjuvant surgery was a significant independent prognostic variable with an adjusted hazard ratio (95 % confidence interval) of 0.569 (0.36-0.89). Subgroup analysis according to the time from initial treatment to surgical resection showed a significant favorable difference in the overall survival in patients who underwent adjuvant surgery over 240 days after the initial treatment. Conclusion: Adjuvant surgery for initially unresectable pancreatic cancer patients can be a safe and effective treatment. The overall survival rate from the initial treatment is extremely high, especially in patients who received non-surgical anti-cancer treatment for more than 240 days.