LOCAL RECURRENCE OF ENDOSCOPIC ROBOTIC ASSISTED SIMPLE ENUCLEATION (ERASE) FOR RENAL CELL CARCINOMA ACCORDING TO PATHOLOGICAL CHARACTERISTICS OF PERITUMORAL PSEUDOCAPSULE: RISULTATI AT A MIDTERM FOLLOW-UP.

Scopo del lavoro The Scopo del lavoro is to evaluate the oncological efficacy of ERASE for RCC and to evaluate the possible relationship between recurrence status and PS infiltration. Materiali e metodi Data were prospectively collected from a cohort of 122 consecutive patients undergoing ERASE performed by four experienced surgeons for organ-confined malignant RCCs at our Institution from November 2010 to December 2013. PS and healthy renal margin (HRM) thickness, PS infiltration and surgical margin status were analyzed by a dedicated uropathologist. Tumor histotype was classified according to the 2012 ISUP Vancouver Classification of Renal Neoplasia. Follow up was recorded at 6, 24 and 48 months. Risultati RCCs were classified as low, medium and high complexity (PADUA score 6-7, 8-9 and ≥10, respectively) in 69.8%, 23.5% and 6.7% of patients, respectively. At histopathological analysis, mean tumor diameter was 3.2 cm ± 1.5 cm. Tumor histotype was: clear cell (cc) RCC in 60.8% of patients, papillary (p) RCC in 14.7%, chromophobe (ch) RCC in 16.3%, multilocular cystic renal neoplasm of low malignant potential (MCCN-LMP) in 4.9% and clear cell papillary RCC (ccpRCC) in 3.3%. Median thickness of PS and HRM were 263.3 (IQR 137.3-444.6) μm and 401.6 (IQR 137.9-921.2) μm. PS was absent in 1.6% of patients. Partial and complete PS infiltration (PS+) were recorded in 39.0% and 17.1% of cases, while it was intact (PS-) in 43.9%. Positive surgical margins were recorded in 2.5% of cases. pT3a stage was recorded in 10.7% of patients. Hilar clamping was performed in 74.6% of cases with a median WIT of 16 min (IQR 13-20). Median estimated blood loss was 100 cc. Intraoperative and postoperative surgical complications occurred in 1 (0.8%) and 9 (7.4%) patients, of which 3 Clavien 2 and 6 Clavien 3. Trifecta rate was 81.1%. At a median follow-up of 41.5 months, only 1 case of local recurrence, located in the omolateral kidney distant from the resection bed, was recorded in a pT1a, ccRCC G2, PS- patient at 13 months. The 3-years local recurrence free survival (LRFS) was 100% while the 5-years LRFS estimate 98.8%. In two patients systemic recurrence of disease was recorded. Of these, one patient died 28 months after surgery. Discussione In our cohort, there was no relationship between the degree of PS infiltration and both surgical margins status and local recurrence. In particular, although positive surgical margins were recorded in 2.5% of cases, no local recurrence was found on the enucleation bed. Conclusioni ERASE, by providing a rim of HRM beyond the peritumoral PS, guaranteed in almost all patients negative surgical margins indipendendly from the PS infiltration and, ultimately, excellent oncologic outcomes. However, further studies are needed to assess the long-term prognostic role of PS infiltration for RCC.