Clinical characteristics, treatment patterns and survival outcomes of early-onset pancreatic adenocarcinoma: a population-based study

Background: Pancreatic ductal adenocarcinoma (PDAC) is a rare and refractory malignancy. Early-onset pancreatic cancer (EOPC), defined as pancreatic cancer diagnosed before the age of 50 years, is very rare. Clini-cal presentation and oncological outcomes of EOPC are confusing according to previous studies. Methods: We performed a retrospective, population-based study by querying the SEER database to analyze patients with PDAC from 2004 to 2018. Data on demographics, pathological characteristics, treatment patterns, and survival outcomes were compared between EOPC and pancreatic cancer in older patients. Propensity score matching (PSM) was used to minimize the potential bias of baseline characteristics between the two groups. The effect of age on changes in treatment modalities was evaluated using the Cochran-Armitage trend test. Results: The entire study enrolled 42,414 patients, including 2,916 (6.9%) patients with EOPC. Patients with EOPC were more likely to be male (56.6% vs. 51.0%, P < 0.001) and more frequently to present with a larger tumor size (40 mm vs. 37 mm, P < 0.001), vas-cular invasion (28.6% vs. 25.9%, P = 0.022) and distant metastasis (56.2% vs. 50.8%, P < 0.001) compared with older group. However, surgical resection rates (29.3% vs. 28.3%, P = 0.284) were fairly comparable, and most clini-copathologic characteristics were similar in the patients underwent resection. Younger patients had longer 5-year overall survival (6.9% vs. 5.5%, P < 0.001) and 5-year cancer-specific survival (8.4% vs. 7.3%, P < 0.001) among the overall cohort but had comparable prognosis among patients received surgery (both P > 0.05). Similar survival outcomes were obtained after PSM. In addition, operated patients tended to receive fewer systemic treatments at an increasing age (Ptrend < 0.001). The survival analysis, which was stratified by age groups, suggested that younger patients only had a better prognosis than those over 70. Conclusions: Patients with EOPC exhibited an advanced stage and a male predilection at diagnosis in the overall cohort but broadly similar clinicopathologic characteristics in the operated patients. In the surgical cohort, although younger patients were more likely to receive systemic treatment, patients with EOPC presented comparable outcomes compared with elderly patients. We suggest that more research should be conducted to uncover the unique characteristics of EOPC for better clinical management.