Investigation of Conversion Surgery for Initial UR-PDAC: Is Adjuvant Chemotherapy Still Necessary?

Abstract

Purpose: The short-term and long-term outcomes of conversion surgery (CS) at our institute were investigated retrospectively. Materials and Methods: CS was defined as a surgery performed with curative intent for patients with unresectable pancreatic ductal adenocarcinoma (UR-PDAC) who first received non-surgical treatment. UR-PDAC was defined using the pancreatic cancer classification of the Japan Pancreatic Society (7th edition). CS was performed for 43 patients from 2011, and the short-term and long-term outcomes of these cases were investigated. Result: There were 42 cases with locally advanced PDAC and 2 cases with metastases. Radiation therapy was performed concomitantly with chemotherapy in 39 cases in the initial treatment. In cases in which we anticipated that the tumor could be safely resected with vascular resection based on the original diagnosis, the initial treatment was performed for 6 months. In all other cases this treatment was performed for at least 8 months. The median observation period was 17 months and CS was performed safely with a median 3-year survival rate of 62%. Pancreaticoduodenectomy (PD) was performed in 24 cases and further vascular resection was required in 28 cases (15 in the portal vein, 15 in the celiac artery, 5 in the common hepatic artery). R0 resection was achieved in 42 cases and adjuvant chemotherapy (AC) was administered in 32 cases (77%). The median recurrence-free survival (RFS) period was 14 months. The rate of overall survival (OS) has yet to reach 50%. Multivariate analysis indicated that normalization of CA19-9 and completion of AC were significant factors for favorable OS and RFS. Conclusion: Certain patients undergoing CS have long-term survival and completion of AC is still important after CS.