Second primary lung cancer in lung cancer survivors: Clinical characterization and screening.

Abstract

e22532 Background: Lung cancer survivors remain at risk for second primary lung cancers (SPLC). However, optimal surveillance strategies are poorly defined, and the incidence, timing, and clinical characteristics of SPLC remain insufficiently characterized. Methods: We conducted a retrospective institutional cohort study including patients with histologically confirmed lung cancer. SPLC was defined as a new primary lung tumor arising after an initial non-metastatic diagnosis. Demographic, clinical, pathological, and outcome data were collected. Eligibility for lung cancer screening was assessed at the time of initial lung cancer diagnosis according to U.S. Preventive Services Task Force (USPSTF) criteria. Group comparisons were performed using chi-square or Fisher’s exact test and t-test or Mann–Whitney test, as appropriate. Results: Among 562 patients with lung cancer, 41 (7.3%) developed a second primary lung cancer (SPLC). The SPLC cohort was predominantly female (70.7%), with a mean age of 63.4 years at SPLC diagnosis. Most patients had a history of smoking exposure (82.1%), while 17.9% were never-smokers. In addition, 30.8% had a prior non-pulmonary primary malignancy. The mean interval between the first and second primary tumors was 53.1 months, frequently exceeding commonly adopted post-treatment surveillance periods. Eleven patients (26.8%) were diagnosed with SPLC outside established screening criteria. Compared with those meeting screening eligibility, patients outside screening criteria were more likely to have adenocarcinoma histology (p = 0.01), to be never-smokers (p < 0.001), to have no history of COPD (p = 0.02), and to present with metastatic disease more frequently (p = 0.03). Conclusions: SPLC frequently develops after prolonged intervals beyond standard surveillance. Nearly one in four cases arise outside current screening criteria and are associated with a higher burden of metastatic disease, underscoring limitations of existing screening frameworks and supporting risk-adapted surveillance strategies for lung cancer survivors.