Rate of renal cell carcinoma subtypes in different races

We sought to identify racial differences among histological subtypes of renal cell carcinoma (RCC) between black and non-black patients in an equal-access health care system.

We established a multi-institutional, prospective database of patients undergoing partial or radical nephrectomy between January 1, 2000 and Sept 31, 2009. For the purposes of this study, data captured included age at diagnosis, race, tumor size, presence of lymphovascular invasion, presence of capsular invasion, margin status, and tumor histology.

204 kidney tumors were identified (Table-1). Of these, 117 (57.4%) were in black patients and 87 (42.6%) were in non-black patients. Age at surgery ranged from 37 to 87 with a median of 62. Tumor size ranged from 1.0 to 22.0 cm with a median of 5.0 cm. Overall, tumors were composed of clear cell RCC in 97 cases (47.5%), papillary RCC in 65 cases (31.9%), chromophobe RCC in 13 cases (6.4%), collecting duct/medullary RCC in 2 cases (1.0%), RCC with multiple histological subtypes in 8 cases (3.9%), malignant tumors of other origin in 6 cases (2.9%), and benign histology in 13 cases (6.4%). Among black patients, papillary RCC was seen in 56 cases (47.9%), compared to 9 cases (10.3%) among non-black patients (p < 0.001) (Table-2). Clear cell RCC was present in 38 (32.5%) of black patients and in 59 (67.8%) of non-blacks (p < 0.001).

In our study, papillary RCC had a much higher occurrence among black patients compared to non-black patients. This is the first study to document such a great racial disparity among RCC subtypes.