Prevalence of Cigarette Smoking among Patients with Different Histologic Types of Kidney Cancer.

Background: Cigarette smoking is causally linked to renal cell carcinoma (RCC). However, associations for individual RCC histologies are not well described. Newly available data on tobacco use from population-based cancer registries allow characterization of associations with individual RCC types.
Methods: We analyzed data for 30,282 RCC cases from 8 states that collected tobacco use information for a National Program of Cancer Registry project. We compared the prevalence and adjusted prevalence ratios (aPR) of cigarette smoking (current vs. never, former vs. never) among individuals diagnosed between 2011 and 2016 with clear cell RCC, papillary RCC, chromophobe RCC, renal collecting duct/medullary carcinoma, cyst-associated RCC, and unclassified RCC.
Results: Of 30,282 patients with RCC, 50.2% were current or former cigarette smokers. By histology, proportions of current or formers smokers ranged from 38% in patients with chromophobe carcinoma to 61.9% in those with collecting duct/medullary carcinoma. The aPRs (with the most common histology, clear cell RCC, as referent group) for current and former cigarette smoking among chromophobe RCC cases (4.9% of our analytic sample) were 0.58 [95% confidence interval (CI), 0.50-0.67] and 0.88 (95% CI, 0.81-0.95), respectively. Other aPRs were slightly increased (papillary RCC and unclassified RCC, current smoking only), slightly decreased (unclassified RCC, former smoking only), or not significantly different from 1.0 (collecting duct/medullary carcinoma and cyst-associated RCC).
Conclusions: Compared with other RCC histologic types, chromophobe RCC has a weaker (if any) association with smoking.
Impact: This study shows the value of population-based cancer registries' collection of smoking data, especially for epidemiologic investigation of rare cancers.
(©2020 American Association for Cancer Research.)