An increasing number of incidental renal masses are detected with more widespread use of ultrasonography, computerized tomography (CT) and magnetic resonance imaging. The incidence of renal cell carcinoma (RCC) has increased by an average of 3% a year since the 1970?s when only 13% of tumors were found incidentally. In 1998, 61% of renal tumors were found incidentally in asymptomatic patients. The increased detection of small incidental renal masses has raised the question about conservative management in a selected group of patients with confounding comorbidities.

A retrospective review of 24 patients with conservatively managed renal tumors was reported by W. Kassouf and his associates from Montreal, Quebec, in the January, 2004, issue of the Journal of Urology. Patients were chosen for observation due to advanced age, poor medical condition or the presence of a mass in a solitary kidney. The average age of the study group was 68.3 years and the mean tumor size was 3.3 cm. Growth rate was calculated based on diameter and tumor volume, and patients were followed for a mean of 31.6 months.

Twenty-two of the 24 patients had solid masses assumed to be RCC, while 2 patients had Bosniak IV complex cysts. T1 disease was present in 92% of patients, and 2 patients (8%) had T3 disease. All patients were followed with regular abdominal imaging every 3 to 6 months, and the majority had CT scans. A mean of 4.4 imaging studies were performed on each patient during the follow-up period.

Analysis of the results showed that only 5 of 24 patients had growth of their tumors during the surveillance period. None developed metastases. Mean tumor size at diagnosis in these five patients was 2.4 cm and the mean growth rate was 0.49 cm or 7.3 cc per year. Four of the five patients underwent surgery during the period of surveillance because of apparent tumor growth or at the patient?s request. All four had RCC with no evidence of metastasis.

Observation seems an acceptable alternative to surgery as an initial step in this type of patient. The authors state also that less invasive surgical procedures such as laparoscopic removal of tumors or ablative procedures such as cryotherapy or high intensity focused ultrasound may be another option in the management of small renal masses in which confounding factors may lead the patient or the surgeon to avoid traditional surgical extirpation.

J. Urol 2004; 171(1):111-3