Smoking May Increase Risk of Death in RCC

Smoking is associated with decreased overall survival in clear-cell RCC.

A history of significant cigarette smoking adversely affected overall survival in patients who underwent surgery for clear-cell renal cell carcinoma, according to the results of a recent study.  In addition, patients with 20 pack-years or greater had a significantly increased risk for death from another cause, the study showed.

“Patients with clear-cell renal cell carcinoma have a high probability of being smokers,” wrote Behfar Ehdaie, MD, MPH, of Memorial Sloan-Kettering Cancer Center and colleagues. “Because effective smoking cessation treatments exist for patients with cancer, the promotion of smoking cessation is warranted in patients with clear-cell renal cell carcinoma who are current smokers or who are at increased risk for relapse after recently quitting.”

According to the study, published in the Journal of Urology, the effect of modifiable environment factors on kidney cancer outcomes is understudied. To look for an association between smoking and advanced disease, Ehdaie and colleagues collected data on the characteristics of 1,625 patients with clear-cell renal cell carcinoma who underwent surgery between 1995 and 2012.

At diagnosis of their disease, 16% of patients were current smokers. Current smokers were more likely to be younger and male. Thirty percent of patients identified as former smokers. Of people who identified as ever having smoked, 73% had a smoking history of 20 pack-years or longer.

The patients were followed for a median of 4.5 years during which time 316 deaths occurred. Metastatic renal cell carcinoma was the cause of 108 deaths; 181 deaths were due to another cause and 27 deaths were from an unknown cause.

Upon univariate analysis, a history of 20 pack-years or longer was significantly associated with the risk for advanced disease (OR = 1.43; P = .036); however, upon multivariate analysis adjusting for age and gender the association lost statistical significance.

The 10-year cumulative incidence of cancer-specific mortality was 8% in never smokers compared with 13% in ever smokers. No significant association between smoking status and renal cell cancer–specific mortality was found.

“However, on univariate analysis P = .057 and the central estimate of the HR (HR = 1.5) on multivariable analysis adjusting for stage and grade indicated a trend toward supporting an association between smoking exposure and cancer specific mortality,” the researchers wrote.

The 10-year cumulative incidence of death attributable to another cause was 17% in smokers with less than 20 pack-years history compared with 30% in smokers with a history of 20 pack-years or longer.  Multivariate analysis showed that smokers with a 20 pack-year history had a significantly increased risk for death from another cause (P < .01).

“The current findings suggest that cigarette smoking exposure adversely impacts overall survival in patients with clear-cell renal cell carcinoma treated with surgery,” the researchers wrote. “Overall our study underscores the importance of promoting smoking cessation in patients with kidney cancer and requiring implementation in survivorship programs.”