Prognostic role of smoking in metastatic renal cell carcinoma in real-world data from the Turkish Oncology Group Kidney Cancer Consortium (TKCC)

Smoking has been implicated as a potential factor influencing cancer progression and outcomes in various malignancies, including metastatic renal cell carcinoma (mRCC). This study aimed to evaluate the effect of smoking status on treatment outcomes in mRCC patients, with a focus on metastatic sites. This retrospective cohort study utilized data from the Turkish Oncology Group Kidney Cancer Consortium (TKCC). The primary endpoint of the study was overall survival (OS) across metastatic sites. A total of 779 patients were included, of whom 464 (58.1%) were former/current smokers. Smoking status did not significantly affect OS in the overall cohort. However, in the bone metastatic subgroup, former/current smokers exhibited worse OS compared to never smokers (33.9 vs. 22.1 months; p = 0.005). Multivariate Cox regression analysis showed that former/current smoking was an independent predictor for OS in patients with bone metastasis (former/current smoker vs never smoker HR 1.44, 95% CI 1.05–1.99; p = 0.026) and bone-only metastasis (former/current smoker vs never smoker HR 4.44; 95% CI 1.27–15.55; p = 0.020) after adjusting for confounding factors. Smoking is an independent predictor of poor survival in mRCC patients with bone metastases, highlighting the organ-specific effects of smoking on cancer progression. Further research is needed to explore underlying mechanisms and evaluate outcomes in the context of modern therapies.