Downstaging in Stage IV Pancreatic Cancer: A New Population Eligible for Surgery?

Background. Recent papers consider surgery as an option for synchronous liver oligometastatic patients [metastatic pancreatic ductal adenocarcinoma (mPDAC)]. In this study, we present our series of resected mPDACs after neoadjuvant chemotherapy (nCT).Patients and methods. All patients resected after downstaging of mPDAC were included in this study. Downstaging criteria were disappearance of liver metastasis and a decrease in cancer antigen (CA) 19-9. The type and duration of nCT, last nCT surgery interval, histology, morbidity, and mortality were recorded, and overall survival (OS) and disease-free survival (DFS) were analyzed.Results. Overall, 24 of 535 patients (4.5%) observed with mPDAC were included. These patients received gemcitabine alone (5/24), gemcitabine + nanoparticle albuminbound (nab)-paclitaxel (3/24), and FOLFIRINOX (16/24). Primary tumor size decreased from 31 to 19 mm (p < 0.001), and serum CA19-9 decreased from 596 to 18 U/mL (p < 0.001). In 14/24 patients, the tumor was located in the head. Median interval nCT surgery was 2 months, there were no mortalities, and the postoperative course was uneventful in 34% of cases. Grade B/C pancreatic fistula, postoperative bleeding, and sepsis occurred in 17/4, 4, and 12% of cases, respectively, and reoperation rate was 4%. R0 resection was achieved in 88% of cases, with 17% complete pathological response. Positive nodes were found in 9/24 patients with a median node ratio of 0.37, and OS and DFS was 56 and 27 months, respectively.Conclusions. Patients with mPDAC who were fully responsive to nCT may be cautiously considered for surgery, with potential benefit in survival compared with palliative chemotherapy alone. This is supported by results of our retrospective study, which is the largest ever reported.