Second malignancy in advanced or recurrent non-small cell lung cancer after the advent of molecular targeted drugs and immunotherapy.

Objectives: This study aimed to investigate the characteristics of patients with recurrent or advanced non-small cell lung cancer (NSCLC) treated with tyrosine kinase inhibitors (TKIs) or immune-checkpoint inhibitors (ICIs) who developed secondary malignancies, as well as evaluate the impact of these secondary malignancies on the course of lung cancer.

Materials and methods: This study included 112 patients with postoperative recurrent or advanced NSCLC, who received TKIs, ICIs, or immune combination therapy as the primary treatment modality between April 1, 2013, and March 31, 2020, and achieved long-term survival (≥2 years). Secondary malignancies were defined as newly diagnosed cancers in other organs occurring after NSCLC treatment initiation.

Results: Among the 112 patients, 10 (8.9%) developed 12 carcinomas, including third primary malignancies. Univariate analysis, considering secondary malignancies as the outcome, revealed a non-significant trend towards a higher incidence of secondary malignancies in smokers compared to non-smokers.

Conclusion: This study found that 8.9% of patients with advanced NSCLC who received TKIs, ICIs, or immune combination therapy and survived ≥2 years developed secondary malignancies. This underscores the importance of early diagnosis and treatment, even during lung cancer treatment, to identify suspicious lesions in other organs either via imaging or physical examinations.