Presentation Authors: Joao Carvalho*, Pedro Nunes, Roberto Jarimba, Edgar Tavares-da-Silva, Hugo Antunes, Belmiro Parada, Pedro Moreira, Edson Retroz, Rui Caetano, Vítor Sousa, Maria Cipriano, Arnaldo Figueiredo, Coimbra, Portugal
Introduction: The impact of positive margins after partial nephrectomy is controversial. The objective was to evaluate the impact of positive surgical margins after partial nephrectomy (PN), looking for factors that could explain them.
Methods: A retrospective study of 388 patients that underwent partial nephrectomy at our institution (424 surgeries) between November 2005 and December 2016 was performed. Two groups were created: positive (PM) or negative (NM) margins groups after partial nephrectomy (PN). The SPSS Statistics 23.0 software was used: independent samples t-student, chi-square, logistic regression and log-rank were done. The p value < 0.05 was considered statistically significant.
Results: Positive surgical margins rate was 3.8% (N=16). The age at surgery was 61.8Â±13.0 years, with a male prevalence (N=270; 63.7%). The patients were mostly asymptomatic (PM:93.8 vs NM:85.8%, p:0.8). The mean imagiological lesion size was 3.4Â±1.7 [0.8-14.7] cm, appearing mainly in the right kidney (50.7%). The lesion location (p:0.3), presence of bilateral (p:0.3) or multifocal (p:0.6) disease and surgical approach (laparoscopic vs open) (p:0.4) had no association with PM. However, surgeon experience matters: if the surgeon had more than 30 surgeries, PM rate was 2.7% vs 10% with less than 30 surgeries performed (p:0.01). The warm ischemia time (PM: 13.8Â±8.6 vs NM: 13.5Â±9.8 min, p:0.9), surgery time (140.3Â±56.5 vs 119.2 Â± 43.5 min, p: 0.06) and hospitalization time (5.1Â±1.9 vs 5.6Â±1.9 days, p:0.8) had no association with PM. However, PM were more frequently seen after haemorrhagic surgeries (25 vs 7.6%,p:0.02). Pathology revealed clear cell (43.8 vs 39.7%), chromophobe (37.5 vs 15.4%) and papillary RCC (18.8 vs 15.9%) in the PM group and angiomyolipoma (0 vs 10%) and oncocytoma (0 vs 8.6%) in the NM group, p: 0.3. High-risk tumours (pT2 or pT3 Fuhrman III or IV) were mostly seen in the PM group (37.5 vs 16.4%,p:0.04), with a higher pathological size (4.2Â±1.7 vs 3.2Â±1.9 cm,p:0.05).Serum creatinine values were similar before [1.0Â±0.5 vs 0.9Â±0.3mg/dL,p:0.3] and after surgery [1.4Â±0.9 vs 1.1Â±0.6 mg/dL,p:0.1]. Complete remission was different [81.2 vs 95.8% (p:0.03)] as well the need for total nephrectomy [25 vs 4.4% (p:0.007)]. However, local recurrence (6.2 vs 2.5%, p:0.4) and overall survival (10.3 Â± 0.8 vs 11.5 Â± 0.1 years since surgery) rate were similar.
Conclusions: Positive surgical margins were associated with fewer surgeon experience, higher pathological size, higher risk tumour and more bleeding surgeries. The renal function was the same and no impact on patient survival was noticed.