Growth characteristics of renal cortical tumors in patients managed by watchful waiting.

OBJECTIVE: To characterize tumor growth of patients managed conservatively for renal cell carcinoma. METHODS: Patients electing conservative management of radiographically determined renal cell carcinomas were referred to a surveillance database. Exclusion criteria consisted of locally advanced disease (>T2) and those with metastatic disease. Clinical follow-up included renal imaging with ultrasound or computed tomography at least every 6 months. RESULTS: Twenty-two patients were originally managed conservatively, two of whom subsequently underwent nephrectomy because of rapid tumor growth. Mean follow-up was 26 months. Mean tumor volume and diameter at presentation was 62.4 cc and 4.08 cm respectively. Overall tumor growth was 24 cc/year by volume or .86 cm/year diameter. CONCLUSIONS: Given the stage migration of incidentally detected renal masses, the natural history of these tumors remains incomplete. Overall tumor growth in selected populations appear to be slow even in those diagnosed with larger masses. These data may be useful in counseling patients and directing further trials on conservative therapy for renal cell carcinoma.