Abstract: PD59-12
Sources of Funding: None

Introduction

As detection of renal masses occurs earlier and at smaller sizes with widespread use of cross-sectional imaging, a significant portion of patients with small renal masses undergo intervention and are found to have benign or low-grade pathology. There is an inverse relationship between the incidence of these masses that have low metastatic potential and size on pre-operative imaging. The purpose of this study is to quantify proportion of low risk masses based on size, and quantify number of low risk masses being surgically removed

Methods

We systematically reviewed the literature for studies that included pathologic findings after surgical removal of renal masses. The studies must state tumor grade and number of benign masses removed stratified by radiographic size. Studies that did not include surgical pathology were excluded.

Results

A total of 602 titles were reviewed for relevance. 144 abstracts were selected and reviewed according to inclusion criteria. Six full text articles that included tumor grade and benign versus malignant histology stratified by tumor size were included. Pooled estimates of low risk renal masses (benign and grade one) were 43.1%, 38.8%, 28.3%, 26.6%, and 15.7% for size groupings 0-2cm, 2-3cm, 3-4cm, 4-6cm and >6cm, respectively. If including grade 2 tumors, the percentages increase, leaving only 6.9%, 11.1%, 17%, 25%, and 33.5% high-grade (grade 3 or 4) tumors in respective size groupings (Figure 1).

Conclusions

The pooled estimates of patients with low grade or benign surgical pathology that had been resected clearly demonstrate a substantial portion of patients with small renal masses that have low metastatic potential are undergoing surgery for removal. As the diameter of a renal mass on preoperative cross sectional imaging decreases, the tumor grade and proportion of malignant pathology does as well. This information is essential to patient counseling and decision-making regarding placement on active surveillance. These findings could be especially helpful in the growing population of elderly patients with significant medical comorbidities.

Funding

None