The investigation of the survival time after recurrence in patients with pancreatic ductal adenocarcinoma for individualization of adjuvant chemotherapy

Purpose: Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease; however, the frequency of recurrence can be reduced if curative surgery following adjuvant chemotherapy is applied. At present, adjuvant chemotherapy is uniformly performed in all patients, as it is unclear which tumor types are controlled best or worst. We investigated patients with recurrence to establish the optimum treatment strategy. Methods: Of 138 patients who underwent curative surgery for PDAC, 85 developed recurrence. Comprehensive clinicopathological factors were investigated for their association with the survival time after recurrence (SAR). Results: The median SAR was 12.6 months. Treatments for recurrence included best supportive care, GEM-based therapy and S-1. The performance status [hazard ratio (HR) 0.12, P < 0.001], histological invasion of lymph vessels (HR 0.27, P < 0.001), kind of treatment for recurrence (HR 5.0, P < 0.001) and initial recurrence site (HR 2.9, P < 0.001) were independent significant risk factors for the SAR. The initial recurrence sites were the liver (n = 21, median SAR 8.8 months), lung (n = 10, 14.9 months), peritoneum (n = 6, 1.7 months), lymph nodes (n = 6, 14.7 months), local site (n = 17, 13.9 months) and multiple sites (n = 25, 10.1 months). A shorter recurrence-free survival (< 1 year) and higher postoperative CA19-9 level were significantly associated with critical recurrence (peritoneal/liver). Conclusions: Several risk factors for SAR were detected in this study. Further investigations are needed to individualize the adjuvant chemotherapy for each patient with PDAC.