The impact of maximum tumor shrinkage of primary site (MTSP) by FOLFIRINOX in the first-line treatment of pancreatic cancer.

356 Background: FOLFIRINOX is the first-line chemotherapy for patients with unresectable pancreatic cancer and yielded a longer overall survival, a superior progression-free survival, a higher objective response rate compared with gemcitabine alone. Maximum tumor shrinkage of primary site (MTSP) was associated with the survival outcome in colon cancer. However the data of tumor shrinkage in pancreatic cancer has not been well-documented. Therefore, we re-evaluated FOLFIRINOX focusing on the tumor shrinkage of primary site. We also assessed impact of tumor shrinkage on survival of unresectable pancreatic cancer. Methods: Medical records were retrospectively reviewed for consecutive patients receiving FOLFIRINOX as the first-line chemotherapy between January and December 2014. Response was evaluated by CT scan every 2 or 3 months until the end of treatment. We analyzed patients’ characteristics and rate of MTSP related to overall survival (OS) and progression free survival (PFS). Results: Thirty one patient...