Solitary solid renal mass: can we predict malignancy?

Abstract

OBJECTIVE To determine the clinical predictors of benign disease in patients with solitary solid renal masses. PATIENTS AND METHODS Pathology reports of patients who underwent radical or partial nephrectomy at two hospitals from 1998 to 2008 were reviewed. Only patients with solitary solid unilateral renal masses were included. Predictors of malignancy risk were assessed with univariate and multivariate logistic regression analysis. RESULTS A total of 592 patients with a mean (SD) age of 60 (13) years were included, 38% of whom were women. Radical and partial nephrectomy was performed in 66% and 34% of patients, respectively. Renal masses were equally distributed on the right and left sides (49% vs 51%, P = 0.84). Masses were more commonly located in the upper and lower poles than in the mid pole (40.8% vs 38.7% vs 20.5%, respectively). The mean tumour size was larger in patients who underwent radical compared with partial nephrectomy (6.8 cm vs 2.9 cm, P < 0.001). The rate of benign disease in our overall population was 9.5%. On univariate and multivariate analysis, only a renal mass size <2 cm and female gender were predictive of benign disease. On further analysis the magnitude of this effect was found to be additive. CONCLUSIONS Renal masses <2 cm and female gender were associated with a higher probability of benign disease. Patient age and tumour location were not predictive of benign disease.