Long-term outcome of small, organ-confined renal cell carcinoma (RCC) is not always favourable

Abstract

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Small, organ-confined renal cell carcinoma (RCC) generally has favourable pathological characteristics and a good prognosis. However, late recurrence is a known characteristic of the biological behaviour of RCC and no consensus has been established for surveillance protocols from 5 years after radical or partial nephrectomy. In the present study with long-term follow-up of patients with small RCCs, 18 of 172 patients (10.5%) with pT1a RCC developed recurrence and eight of these (4.7%) died from cancer. Patients with microvascular invasion had a higher risk for cancer death than those without (P < 0.001, Log-rank test). Therefore long-term follow-up is required after surgery, particularly when the disease has microvascular invasion.

Objectives: To identify the long-term clinical course of small, organ-confined renal cell carcinoma (RCC). To detect the risk factors of recurrence and of cancer death in small RCC.

Patients and methods: Retrospectively reviewed 172 patients who were pathologically diagnosed as having pT1a RCC without metastasis at our institution from 1980 to 2005. All pathology slides were re-reviewed by a single experienced pathologist. Associations of microvascular invasion (MVI), development of metastasis, and cancer death were evaluated using Cox proportional hazards analysis.

Results: During a median (range) follow-up of 104.5 (8-308) months, 18 patients (10.5%) developed progression and eight patients (4.7%) died from cancer. Kaplan-Meier curves showed higher cancer-specific survival (CSS) in patients without MVI (P < 0.001). In multivariate analysis, MVI was the only factor that reached statistical significance (P = 0.006). The 10-year CSS rates were 85.1% and 96.5% in patients with and without MVI, respectively.

Conclusions: Patients with MVI have worse survival than those without MVI. This suggests that long-term follow-up of patients with small RCCs is needed because of the risk of recurrence and cancer death even 10 years after surgery, particularly when the disease has apparent MVI.