The Optimal Surgical Margins of Nephron-sparing Surgery for Stage T_1b Renal Tumors

  Objective  To analyze the pathological characteristics and explore the optimal surgical margins (SM) of nephron-sparing surgery (NSS) for stage T_1b renal carcinoma (4–7 cm) on preoperative imaging.

  Methods  The clinical and pathological data of 245 cases of stage T_1b kidney cancer from September 2013 to December 2017 were collected and reviewed retrospectively. The radical nephrectomy (RN) was performed on 174 cases and other 71 cases accepted NSS. There were 158 males and 87 females, with a mean age of 59.6 years and mean tumor size of 5.3 cm.

  Results  Through postoperative pathological examination, 209 (85.3%) cases were confirmed renal clear cell carcinoma and 219 (89.4%) cases were surrounded with visible peritumoralpseudocapsule (PC). 26 (10.6%) cases of cancerous cells invaded beyond peritumoral PC and into renal parenchyma. The infiltrative depth into renal parenchyma beyond PC was all limited in 3 mm and the cases of ≤1, 1-2 and 2-3 mm were 7 (26.9%), 16 (61.5%) and 3 (11.5%), respectively. Multifocal tumors were discovered in 24 (9.8%) cases. The average resection margin for partial nephrectomy was 5 mm (3-7 mm).

  Conclusion  For stage T_1b renal tumors, NSS is acceptable and a 3 mm of surgical margin is safe and suitable to avoid positive SM.