The prognostic value of DNA ploidy in small renal cell carcinoma

The objective was to study the prognostic value of Deoxyribonucleic Acid (DNA) ploidy status in small renal cell carcinomas (RCC). The nuclear DNA content of renal cell carcinoma tissues from patients who underwent radical or partial nephrectomy has been analyzed by flow cytometry. The results of the DNA ploidy have been correlated to the size of tumors and disease progression. Of the 50 patients with RCC studied, 8 (16%) progressed. Tumors with non-diploid DNA patterns were found in 24 (48%) of the 50 patients and in 4 of the 8 patients who progressed. Overall the median tumor size in our series was 50 mm. A tumor diameter of 50 mm or less was measured in 26 patients (group I) and above 50 mm in 24 (group II). Non-diploid DNA patterns were found in 11 (42.3%) and 13 (54.2%) patients in groups I and II, respectively. This difference between the groups was not significant. Only one patient in group I (3.8%) developed metastatic disease and died 72 months after the operation. In group II, 7 patients (29.2%) presented tumor progression and 5 died of metastatic disease. The survival probability in group I was 95% at 5 and 8 years (95% CI 70% to 99%) and for group II 94% at 5 years (95% CI 67%-99%) and 67% at 8 years (95% CI 39%-83%). DNA ploidy is an inaccurate predictor of tumor behavior in patients with RCC, even in small tumors. Tumor size is a more significant predictor of outcome.