Abstract
BACKGROUND: Lung-only relapse following resection of pancreatic ductal adenocarcinoma (PDAC) is rare. While oligometastatic lung disease (OMLD) is detected after PDAC resection, its clinical and molecular features remain unclear. Our goal was to assess if lung metastatic lesion quantity and mutations could predict a better prognosis. MATERIALS AND METHODS: We carried out a multicentric retrospective analysis of clinical and genomic characteristics in PDAC patients with OMLD and compared them with those with non-oligometastatic lung-only disease (non-OMLD). RESULTS: Thirty-nine patients meeting inclusion criteria were analyzed (OMLD n = 18, non-OMLD n = 21). OMLD exhibited more frequent unilateral location (87.5% versus 0%) and late recurrence (88.9% versus 47.6%) compared to non-OMLD. The median disease-free survival in patients with OMLD was 23.2 months versus 10.7 months in those with non-OMLD [hazard ratio (HR) 0.52, 95% confidence interval (CI) 0.27-1]. Moreover, OMLD patients had a longer median overall survival (35.7 months) compared to non-OMLD patients (26.2 months) (HR 0.34, 95% CI 0.12-0.96). Both groups shared common PDAC driver mutations (KRAS, TP53, CDKN2A, and SMAD4). Two OMLD patients had pathogenic DNA damage repair gene mutations. CONCLUSIONS: Our study shows an OMLD incidence of 3.4% in PDAC patients after surgical resection. Patients with OMLD have distinct clinical characteristics compared to those with non-OMLD. PDAC driver mutations were found at similar rates in both groups. Further studies are needed for better understanding of OMLD and treatment strategies.