Image-guided biopsy of small renal masses in the era of ablative therapies

Objective To further evaluate the accuracy, safety, and impact of image-guided renal biopsies on clinical decision making and management of the indeterminate small renal masses. Methods A total of 145 patients (males 99, females 46) with small renal masses suspicious for malignancy were evaluated during the study period. The patients' mean age was 67.2 (+/- 11.6)years. Computed tomography guided biopsies were carried out in all cases by an experienced interventional radiologist. An experienced genitourinary pathologist reviewed all pathological specimens. Patients' demographic characteristics, tumor histology and subsequent intervention, as well as periprocedural morbidities were recorded and analyzed. Results A total of 145 renal biopsy procedures were carried out. The small renal masses mean size was 2.4 +/- 1.1cm. Biopsy was diagnostic in 126 (86.9%) cases and non-diagnostic in 19 (13.1%) cases. Of diagnostic biopsies, 107 (84.9%) were malignant, 84.1% of which were primary renal cell carcinoma. Histological subtyping and grading of tumor was possible in 100% and 52.2% of renal cell carcinomas, respectively. The major renal cell carcinoma subtype was clear cell (63.3%) followed by papillary (24.4%) and chromophobe (8.8%). Repeat biopsy was carried out in nine of 19 non-diagnostic cases, and diagnosis was possible in 66.7%. Sensitivity of percutaneous renal biopsy was 91%, and its accuracy was 85.5%. Overall, patients' age, sex, tumor size, and location were not related to non-diagnostic biopsy results and/or tumor pathology. No cases of hemorrhage, seeding of biopsy tract, infection or mortalities were observed. Conclusions Our findings showed that image-guided biopsy of indeterminate small renal masses is safe and can provide the correct diagnosis with a high degree of accuracy. Thus, this procedure can play an important role in establishing a histopathological diagnosis before treatment of enhancing small renal masses with ablative technologies. Furthermore, repeat biopsy can alter the clinical management of non-diagnostic biopsies.