Impact of smoking on immunotherapy outcomes in cancer: A multi-center retrospective analysis.

Abstract

e14658 Background: Smoking is a well-established risk factor for cancer progression and treatment-related adverse events. Its influence on immunotherapy outcomes remains an area of interest, particularly across diverse cancer types. This study evaluates the association between smoking, progression-free survival (PFS), and high-grade adverse events in cancer patients undergoing immunotherapy. Methods: A retrospective analysis of 100 cancer patients (52 females, 48 males) receiving immunotherapy was conducted. Cancer types included lung (36%), head and neck (34%), and breast cancers (30%). Smoking prevalence was 50%, and comorbidities (e.g., diabetes, hypertension) were documented. Statistical analyses (chi-square tests) evaluated associations between smoking, PFS, and Grade III/IV adverse events, while median PFS was compared by cancer type and smoking status. Results: Smokers exhibited a significantly shorter median PFS (9.8 months) compared to non-smokers (14.7 months; χ² = 13.71, p = 0.0002). This effect was most pronounced in patients with head and neck cancers and those with comorbidities. Smokers also faced an increased risk of severe immune-related adverse events (Grade III/IV toxicities: 42% in smokers vs. 20% in non-smokers; χ² = 7.29, p = 0.03). The most common side effects were pneumonitis (38%), joint pain (25%), and asthenia (20%), with higher severity grades in smokers. Conclusions: Our findings demonstrate a significant negative impact of smoking on immunotherapy outcomes, including PFS and adverse event severity. The data highlight the importance of smoking cessation programs tailored to cancer patients to improve therapeutic efficacy and minimize complications. Future studies should explore underlying biological mechanisms and therapeutic strategies to mitigate these effects. Comparison with Existing Literature: In contrast to recent literature focusing on lung cancer, such as Luo et al. (2024), which found no significant difference in immunotherapy efficacy between smokers and non-smokers (HR for OS: 0.74 vs. 0.73), our study emphasizes the broader population and progression-free survival. This discrepancy underscores the need for further research across diverse cancer populations. Demographic table. Characteristic Overall (n = 100) Smokers (n = 50) Non-Smokers (n = 50) Gender, n (%) - Female 52 (52%) 22 (44%) 30 (60%) - Male 48 (48%) 28 (56%) 20 (40%) Cancer Type, n (%) - Lung 36 (36%) 20 (40%) 16 (32%) - Head and Neck 34 (34%) 18 (36%) 16 (32%) - Breast 30 (30%) 12 (24%) 18 (36%) Common Comorbidities, n (%) - Diabetes 20 (20%) 12 (24%) 8 (16%) - Hypertension 15 (15%) 9 (18%) 6 (12%) Median PFS (Months) 12.425 9.8 14.7 Grade III/IV Adverse Events, n (%) 31 (31%) 21 (42%) 10 (20%)