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

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.