Impact of smoking cessation on survival and treatment tolerability in advanced non-small cell lung cancer: a single-center experience from Morocco.

Background: Smoking cessation following a lung cancer diagnosis presents a dual challenge, as patients must cope with both the emotional burden of cancer and nicotine dependence. This study aimed to evaluate the impact of smoking cessation on overall survival (OS) and treatment tolerability in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC). Methods: This retrospective cohort study included patients with stage III-IV NSCLC treated at the National Institute of Oncology, Rabat, Morocco, between January 2022 and December 2023. Patients were classified as ex-smokers (n = 60), who quit smoking at diagnosis or active smokers (n = 40), who continued smoking thereafter. Smoking cessation support was individualised and included medical counselling, psychological support, nicotine replacement therapy and referral to specialised cessation consultations. Outcomes assessed included treatment response, adverse events and OS.M. Results: Among 100 patients (mean age 69 ± 9 years), there were no significant differences between groups in disease stage (p = 0.70) or histology (p = 0.63). Treatment intolerance occurred in 55% of patients, with adverse events more frequent in active smokers (39%) than in ex-smokers (16%). Haematologic toxicity, particularly neutropenia, was significantly higher in active smokers (p < 0.001). Notably, patients who quit smoking during treatment experienced improved treatment tolerability. Median OS was 10 months overall, with longer survival in ex-smokers (11 months) compared with active smokers (7 months) (log-rank p < 0.001). Conclusion: Smoking cessation at diagnosis is associated with reduced treatment-related toxicity and improved survival in advanced NSCLC, supporting its role as an independent prognostic factor and a priority in clinical management.