Flow cytometric assessment of deoxyribonucleic acid content in renal adenocarcinoma: does ploidy status enhance prognostic stratification over stage alone?

Flow cytometry was used to analyze deparaffinized primary renal cell carcinoma specimens from 106 patients to evaluate deoxyribonucleic acid ploidy as a predictor of disease progression and survival. Of these specimens 62 (58%) demonstrated aneuploid stem lines: 30 (48%) of these were tetraploid aneuploid while 32 were nontetraploid aneuploid. Two or more specimens were analyzed from a single primary tumor in 17 patients and heterogeneity of ploidy status was observed in 5 (30%). Specimens of the primary tumor, and regional and/or distant metastases from 11 patients were analyzed; 5 (45%) demonstrated discordance between the ploidy of the primary and the metastatic site. A significant correlation was noted between the presence of aneuploid stem lines and high stage disease (p equals 0.004) but there was no significant correlation between ploidy status and tumor grade. Although there was a significant difference (p equals 0.037) in the incidence of disease progression in patients with diploid tumors (13%) versus those with aneuploid tumors (35%) in the total population, and Kaplan-Meier disease-specific survival curves demonstrated a survival advantage for patients with diploid tumors in the total population, no clear survival advantage was demonstrated for evaluable patients with diploid tumors when controlled for tumor, nodes and metastases stage. In conclusion, the heterogeneity of ploidy status in primary renal cell carcinoma, the high incidence of disease progression in patients with diploid primary tumors and the lack of a clearly demonstrable stage-independent impact of ploidy on prognosis currently would not support widespread clinical application of ploidy status of the primary tumor in the management of individual patients with renal cell carcinoma.