Renal cell cancer histological subtype distribution differs by race and sex

Abstract

Objectives: To examine racial differences in the distribution of histological subtypes of renal cell carcinoma (RCC) and associations with established RCC risk factors by subtype.

Materials and methods: Tumours from 1532 consecutive patients with RCC who underwent nephrectomy at Vanderbilt University Medical Center (1998-2012) were classified as clear-cell, papillary, chromophobe and other subtypes. In pairwise comparisons, we used multivariate logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between race, sex, age, end-stage renal disease (ESRD) and body mass index at diagnosis according to histological subtype.

Results: The RCC subtype distribution was significantly different in black people from that in white people (P < 0.001), with a substantially higher proportion of patients with papillary RCC among black people than white people (35.7 vs 13.8%). In multivariate analyses, compared with clear-cell RCC, people with papillary RCC were significantly more likely to be black (OR 4.15; 95% CI 2.64-6.52) and less likely to be female (OR 0.60; 95% CI 0.43-0.83). People with chromophobe RCC were significantly more likely to be female (OR 2.32; 95% CI 1.44-3.74). Both people with papillary RCC (OR 6.26; 95% CI 2.75-14.24) and those with chromophobe RCC (OR 7.07; 95% CI 2.13-23.46) were strongly and significantly more likely to have ESRD, compared with those with clear-cell RCC.

Conclusion: We observed marked racial differences in the proportional subtype distribution of RCCs diagnosed at a large tertiary care academic centre. To our knowledge, no previous study has examined racial differences in the distribution of RCC histologies while adjusting for ESRD, which was the factor most strongly associated with papillary and chromophobe RCC compared with clear-cell RCC.

Keywords: end-stage renal disease; histology; race; renal cell cancer; sex.