Impact of smoking status on survival after cytoreductive nephrectomy for metastatic renal cell carcinoma

To assess the association of smoking status with standard clinicopathological features and overall survival (OS) in a large multi-institutional cohort of patients with metastatic renal cell carcinoma (mRCC) treated with cytoreductive nephrectomy (CNT). A total of 613 patients with mRCC treated with CNT in US and Europe institutions between 1990 and 2013 were included. Smoking history comprised smoking status, smoking duration in years, number of cigarettes per day and years since smoking cessation. Cumulative smoking exposure was categorized as light short term, heavy long term and moderate. Association between smoking history and OS was assessed by Cox regression logistic analysis. One hundred and seventy-one patients (27.9 %) never smoked, 193 (31.5 %) were former smokers and 249 (40.6 %) were current smokers. Smoking status was associated with a higher number of metastases (p < 0.001) and an abnormal preoperative corrected calcium level (p = 0.01). Median follow-up was 16 (IQR 7-24) months. Current smokers had a shorter OS than never and former smokers (log rank, p = 0.004). Smoking status was significantly associated with OS in univariable analysis (HR 1.45; 95 % CI 1.16-1.82; p < 0.001), and in multivariable analysis that adjusted for established prognostic factors (HR 1.46; 95 % CI 1.16-1.84; p = 0.002). Daily consumption of more than 20 cigarettes, more than 20 years of smoking exposure and heavy long exposure were all independent prognosticators of worse OS. Current smoking and a higher cumulative smoking exposure are associated with a higher risk of death in patients with mRCC treated with CNT. Even at this stage, smoking negatively affects kidney cancer outcomes.