BACKGROUND: With improvement and availability of CT scanners, there has been an increase in the incidence of small renal masses and a corresponding rise in both the overall number of nephrectomies and the number of partial nephrectomies. Little is known, however, about the pathological tumor characteristics of these masses, specifically whether a trend toward lower grade and benign renal masses can be discerned.
METHODS: Patients who underwent surgery for renal masses between 2000 and 2006 in a tertiary referral center were identified by CPT code. For two of these years, the procedural codes were incomplete; these years were excluded from analysis. Transplant nephrectomies, trauma nephrectomies, and nephroureterectomies were likewise excluded from analysis. Records were retrospectively reviewed for patient demographics, surgical technique, and tumor pathology.
RESULTS: A total of 476 radical and partial nephrectomies were available for analysis. Populations of patients undergoing nephrectomy were comparable for the years 2000 to 2006 with respect to age (62.1 +/- 12.196 years) and gender (56.1% male, 43.9% female). Significant linear trends toward partial nephrectomy (18.6% to 52.4%, p<.001) and minimally invasive surgery (44.3% to 83.5%, p<.001) were noted, comparable to similar tertiary care centers. A significant linear trend toward decreasing overall tumor size was also seen (9.134 to 5.088cm, p<.001). No significant change, however, was noted in the size of the tumors of those undergoing partial nephrectomy (3.148 +/- 1.7395cm). The percentage of benign disease has remained stable (18.1%), however, there was a significant difference among tumors removed by partial (23.9% benign) and radical (14.4% benign) nephrectomy (p<.01). There was a small but statistically significant correlation between year and tumor grade with lower grade tumors seen in more recent years (p<.02). Among partial nephrectomies, however, tumor grade was comparable for each year.
CONCLUSIONS: In a contemporary population of patients undergoing surgery for renal masses within a single tertiary care center, there has been a recent increase in the number of nephrectomies and in the proportion of partial nephrectomies performed by year. There has been no increase in the overall number of benign renal masses being removed over the same time period. There is however, a trend toward smaller renal tumors and lower grade tumors.