Field Cancerization and Recurrence Patterns After Resection of Pulmonary Squamous Cell Carcinoma

Background/Aim: Distinguishing a second primary pulmonary squamous cell carcinoma (SCC) from pulmonary metastasis after head and neck or esophageal SCC is challenging. We compared postoperative outcomes and event patterns to investigate whether field cancerization may contribute to long-term prognosis after pulmonary resection. Patients and Methods: We retrospectively analyzed 238 patients who underwent pulmonary resection for SCC between 2015 and 2023: 172 without prior aerodigestive SCC (LC), 21 with pulmonary lesions judged to be independent primary cancers after prior aerodigestive SCC (MPC), and 45 with lesions judged to be pulmonary metastases (PM). Overall and post-event survival were estimated using the Kaplan–Meier method. Cumulative incidences of field cancerization-related new primary cancers and distant recurrence were estimated using competing-risks methods. Results: Five-year overall survival was lowest in the MPC group (41.3% vs. 56.7% in LC and 57.8% in PM; p=0.046), whereas post-event survival was similar among groups (p=0.993). The 5-year cumulative incidence of field cancerization-related new primary cancers was highest in MPC (18.5% vs. 4.1% in LC and 0% in PM; p=0.004), whereas distant recurrence was recorded more often in PM (41.6% vs. 10.7% in LC and 9.5% in MPC; p<0.001). Conclusion: Field-related new primary cancers were recorded more often in MPC, and distant recurrence more often in PM. These patterns may reflect field cancerization and differences in event classification.