Prognostic significance of subclassifying stage pT3a renal tumors with fat invasion: a retrospective study of 99 patients.

PURPOSE

To analyze the recurrence in patients with clinic stage T1 renal cell carcinoma (RCC) who were upstaged to stage T3a after partial nephrectomy (PN) using a new sub-classification criterion.

METHODS

A retrospective study of pathological characteristics was performed in patients who were upstaged to pT3a on the basis of fat invasion (FI).

RESULTS

After analyzing the pathological findings, we proposed the following new sub-classification criteria for pT3a RCC with FI: (1) renal tumor invades the pseudo-capsule and contacts the perinephric adipose tissue directly or the tumor protrudes into the perinephric adipose tissue like a tongue (Type A); and (2) tumor nodules are distributed in perinephric adipose tissues (Type B). A significant difference was observed in the recurrence rate between the two subtypes A and B. For Type B, the recurrence rate after radical nephrectomy (RN) and PN was 15.79% and 63.64%, respectively. The recurrence rates for Types A and B after PN were 11.11% and 63.64%, respectively.

CONCLUSIONS

T3a RCC with tumor nodules in perinephric adipose and/or an irregular tumor protruding into the adipose tissues lead to a higher recurrence rate. We recommend that T3a RCC be carefully analyzed and patients be treated on an individual basis.