Does Surgical Resection Significantly Prolong the Long-Term Survival of Patients with Oligometastatic Pancreatic Ductal Adenocarcinoma? A Cross-Sectional Study Based on 18 Registries.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a type of lethal gastrointestinal malignancy. It is mainly discovered at, and diagnosed with, an advanced stage of metastasis. As the only potentially curative treatment for PDAC, surgical resection has an uncertain impact on the survival of these patients. As such, we aimed to investigate if patients with metastatic PDAC (mPDAC) benefit from surgery. Methods: Patients with pancreatic cancer in 18 registries of the Surveillance, Epidemiology, and End Results database between 2000 and 2018 were reviewed retrospectively. According to the American Joint Committee on Cancer (AJCC), the eighth edition staging system was utilized. Propensity score matching was applied to strengthen the comparability of the study. The impact of surgery on survival was evaluated by restricted mean survival time (RMST) and Kaplan−Meier analysis. Results: A total of 210 well-matched mPDAC patients were included in the study. The 1 year, 3 year, and 5 year overall survival (OS) of patients undergoing surgery was 34.3%, 15.2%, and 11.0%, respectively. The 1 year, 3 year, and 5 year cancer-specific survival (CSS) of these patients was 36.1%, 19.7%, and 14.2%, respectively. RMST analysis revealed that mPDAC patients with surgery had better OS and CSS than those without (OS: 9.49 months vs. 6.45 months, p < 0.01; CSS: 9.76 months vs. 6.54 months, p < 0.01). Nevertheless, subgroup analysis demonstrated that such statistical significance especially existed in oligometastatic PDAC patients, which refers to those metastases that were limited in number and concentrated to a single organ in this study. Additionally, surgery was identified as a significant predictor for the long-term prognosis of patients (OS: [HR, hazard ratio] = 0.48, 95% CI: 0.36−0.65, p < 0.001; CSS: HR = 0.45, 95% CI: 0.33−0.63, p < 0.001). Lastly, a nomogram was established to predict whether an individual was suitable for surgical treatment in this study. Conclusions: Surgical resection significantly prolonged the long-term prognosis of oligometastatic PDAC patients. Such insights might broaden the management of patients with mPDAC to a large extent. However, a prospective clinical trial should be conducted before a recommendation of surgery in these patients.