Login to Access Video or Poster Abstract: MP72-07
Sources of Funding: none

Introduction

In recent years, large series of tumor enucleation (TE) for renal masses have showed equivalent functional and oncological results compared with standard partial nephrectomy. However, few objective assessments and pathologic evidence of enucleation tumor bed have been reported. This study was designed to assess the feasibility and histopathologic safety of tumor enucleation for renal cell carcinoma, through histopathologic analysis of the tumor bed after in vitro tumor enucleation.

Methods

We studied 246 radical nephrectomy specimens for clinical T1 RCC in our institution, from January 2013 to December 2015. Immediately after the kidney was excised, the tumor of radical specimen was enucleated in vitro in the same fashion as open or laparoscopic kidney tumor enucleation. The tumor bed parenchyma of 15 mm beyond the pseudocapsule were continuously sectioned and examined to investigate the possible presence of tumor invasion or satellite lesions.

Results

The study involved 246 patients, consisting of 148 men (60.2%) and 98 women (39.8%), with a mean age of 60.9±10.3 years. The average tumor size was 5.3±1.7 cm. The histopathologic evaluation revealed that 82.5% of tumors were clear cell RCC, 7.7% were papillary, and 6.5% were chromophobe. The pathological staging showed that 23.2% of tumors were pT1a, 68.3% were pT1b, 3.7% were pT2, and 4.9% were pT3a.On the basis of Fuhrman nuclear grading, 171 lesions (69.5%) were grade 1-2 and 75 (30.5%) were grade 3-4. The incidence of positive surgical margins was 3.3%. For the pathological characteristics of tumor bed, tumor infiltration was detected in 5 cases (2.0%) and satellite lesion was detected in 4 cases (1.6%). In the group of 60 primary tumors 4 cm or less in diameter, 3 (5.0%) were found with residual tumor, 1 with tumor infiltration and 2 with satellite lesion. In the group of 186 primary tumors larger than 4 cm, 6 (3.2%) were found with residual tumor, 4 with tumor infiltration and 2 with satellite lesion. Statistically, there was no significant difference (p=0.809). In the group of grade 1-2, 4 (2.3%) were found with residual tumor, and 5 (6.7%) in the group of grade 3-4 (p=0.195). Median follow-up was 24 months (range 8-43) with a recurrence rate of 4.1% (10 of 246) and a cancer specific mortality rate of 2.4% (6 of 246).

Conclusions

The risks of tumor infiltration and/or satellite lesions of enucleation tumor bed are relatively low. Tumor enucleation is a histopathologically safe technique for patients undergoing partial nephrectomy.

Funding

none