Intracapsular clear cell renal carcinoma: ploidy status improves the prognostic value of the 2002 TNM classification.

Purposes: The TNM classification has been revised for the 2002 edition of the UICC publication to better stratify patients with intracapsular renal cell carcinoma (RCC) but few studies have been published to date to validate this new classification. Moreover, additional prognostic factors seem to be necessary to improve the prediction of intracapsular tumor aggressiveness and the definition of patient subgroups at high risk for metastases. We report the long-term results of the new TNM scheme. We evaluated the impact of DNA content, S-phase and MIB-1 (Dako, Glostrup, Denmark) score.

Materials And Methods: A total of 136 patients with intracapsular clear cell RCC and a mean followup of 74 months were reclassified. Tumor specific survival (TSS) was compared with nuclear grade (NG), DNA content and proliferative status (S-phase fraction and MIB-1 score).

Results: TSS was 92%, 81.1% and 40.1% for pT1a, pT1b and pT2, respectively (p <0.05). TSS according to DNA ploidy status (diploid vs aneuploid) was pT1a-95.2% vs 68.6% (p <0.05), pT1b-90% vs 46.7% (p <0.05) and pT2-49.2% vs 25% (p not significant). DNA ploidy was also significantly associated with survival when adjusted for NG. There was no significant association between TSS and MIB-1 score or tumor S-phase fraction.

Conclusions: The 2002 TNM classification is a useful prognostic factor for evaluating organ confined RCC of the clear cell subtype. Evaluation of the DNA content in clear cell RCC appears to significantly improve the predictive value of the TNM staging system, especially in the pT1a and pT1b categories. Fuhrman NG alone or combined should be routinely used in such patients.