Conversion surgery for initially unresectable pancreatic ductal adenocarcinoma following induction therapy: a systematic review of the published literature.

Patients with unresectable pancreatic ductal adenocarcinoma (UR-PDAC) are traditionally treated with palliative chemotherapy. The aim of this study was to evaluate the safety and efficacy of conversion surgery for initially UR-PDAC following induction therapy. The PubMed and Embase databases were systematically searched for eligible studies published between January 2000 and October 2020. Thirty-two series involving 1270 patients with 1056 locally advanced (LA) disease and 214 distant metastases were reviewed. The median mortality and morbidity was 0% (range 0-10%) and 47.1% (range 8.6-93.3%), respectively. Lymph-node negativity, negative resection margin and pathological complete response were observed in a median of 62.9% (38.5-90.9%), 84.4% (32.8-100%) and 6.7% (0-45.8%) of the specimens. The median survival was 32 (16.4-63.9) months with a 3-year survival rate of 47% (22-80%). Meta-analysis demonstrated that conversion surgery of initially UR-PDAC was associated with a significantly improved survival (hazard ratio [HR] = 0.55; 95% confidence intervals (CI) 0.45-0.66, P < 0.001). There was no significant difference in survival between the group with LA disease and that with distant metastases after conversion surgery (HR = 0.96; 95% CI 0.72-1.28, P = 0.790). Conversion surgery improved long-term survival of patients with initially UR-PDAC who had favorable response to induction therapy.