Positive surgical margins predict progression-free survival after nephron sparing surgery for renal cell carcinoma: Results from a single centre cohort of almost 500 cases with a minimum follow-up of 5 years
The real role of positive surgical margins (PSM) after nephron sparing surgery (NSS) on progression and relapse of disease is still debated because strong evidences are lacking, especially at a long term horizon. The aim of this study was to evaluate the oncologic impact of PSM in a large contemporary single centre cohort of PN followed for a long time.
A retrospective analysis of our prospectively maintained institutional database on renal surgery since 1983 was performed. The indication to radical versus partial nephrectomy (PN) followed the contemporary international guidelines; the surgical strategy for PN was generally an enucleoresection. All surgical specimens were examined by two expert uro-pathologists. For the present study, all patients who underwent PN for non metastatic RCC with at least 5 years of follow-up, if uneventful, were included; the patients died from non cancer causes within the minimum time of follow-up required were excluded. A PSM was defined as the presence of cancer cells at the inked surface of the final specimen. The primary endpoint was progression free survival (PFS), considering as events of progression all recurrences of disease at any site. A Cox regression model estimated the role of PSM on survival, after adjustment for influent covariates.
Out of 490 patients submitted to NSS for RCC, 459 patients fulfilled inclusion criteria and were evaluated for the purpose of this study. PSM were observed in 27 (5.9%) cases. No differences in terms of preoperative and pathological features of patients with positive and negative surgical margins (NSM) were found. At a mean follow-up of 110 (±51.9) months, progression was diagnosed in 36 (7.8%) patients overall. Among these patients, 6 had PSM (6 out 27, 22.2%) and 30 (out of 432, 6.9%) had NSM (p= 0.013). The sites of progression were distant organs in 18 cases and the operated kidney in 21. No differences were found in terms of incidence of distant metastasis between PSM and NSM groups, whereas there was a significant difference in the incidence of relapses on the operated kidney (14.8% versus 3.9%; p= 0.029). At multivariable Cox regression analysis, a PSM was confirmed as an independent predictor of survival [OR: 3.127 (IQR 1.272 – 7.688); p=0.013].
A PSM is an independent predictor of PFS in patients submitted to NSS for RCC and followed for a long time, mainly due to a higher rate of local relapses of disease. In these patients, a tailored follow-up is mandatory.