ABSTRACT Objectives: The clinical significance of positive surgical margin (PSM) after a Nephron Sparing Surgery (NSS) is controversial. The aim of this study is to evaluate the association between PSM and the risk of disease recurrence in patients with pT1 kidney tumors who underwent NSS. Materials and Methods: Retrospective cohort study. A total of 314 patients submitted to a NSS due to stage pT1 renal tumor between January 2010 and June 2015 were included. Recurrence-free survival was estimated. The Cox model was used to adjust the tumor size, histological grade, pathological stage, age, surgical margins and type of approach. Results: Overall PSM was 6.3% (n=22). Recurrence was evidenced in 9.1% (n=2) of patients with PSM and 3.5% (n=10) for the group of negative surgical margin (NSM). The estimated local recurrence-free survival rate at 3 years was 96.4% (95% CI 91.9 to 100) for the NSM group and 87.8% (95% CI 71.9 to 100) for PSM group (p=0.02) with no difference in metastasis-free survival. The PSM and pathological high grade (Fuhrman grade III or IV) were independent predictors of local recurrence in the multivariate analysis (HR 12.9, 95%CI 1.8-94, p=0.011 / HR 38.3, 95%CI 3.1-467, p=0.004 respectively). Fuhrman grade proved to be predictor of distant recurrence (HR 8.1, 95%CI 1.6-39.7, p=0.011). Conclusions: The PSM in pT1 renal tumors showed to have higher risk of local recurrence and thus, worse oncological prognosis.

The aim of this paper is to describe the epidemiological characteristics, clinical management and pathologic patterns in a population with renal tumors in our institution. Prospective data collection was performed over a period of 4.5 years, from January 2010 to June 2014. A total of 819 cases (796 patients) were treated for renal mass during this period. The mean age was 60.7 years (SD 13.1). There were 553 (69.5%) males (male to female ratio: 2.2: 1). Twenty nine per cent (230 patients) were obese (BMI ≥ 30). The diagnosis was incidental in 653 cases (79.7%), 48.8% presented one or more risk factors, being smoking the most frequent (34%). In 238 patients (29.9%) there was more than one comorbidity; 18% had preoperative creatinine ≥ 1.3 mg/dl. Lesions were ≤ 4 cm (cT1a) in 45% of the patients, and 10.8% (86) had metastases at diagnosis. The lesions were resected in 93.5% and actively monitored in 6.5% (not resected). In surgery treated patients, radical nephrectomy was performed in 51.5% of cases, and nephron sparing surgery in 48.5% of them. The laparoscopic approach was used in 56.2%. The pattern of presentation of renal masses is characterized by incidental diagnosis in early disease stages. Nephron sparing surgery is the first choice in nearly half of patients. Active surveillance has been used in a greater percentage than previously reported.

El objetivo del trabajo es describir las características epidemiológicas de la población con tumores renales en nuestra institución, la estrategia de diagnóstico y tratamiento y los hallazgos anatomo-patológicos. Se realizó una recolección prospectiva de datos epidemiológicos, de diagnóstico y tratamiento, así como también de los resultados patológicos en un período de 4.5 años, desde enero de 2010 a junio de 2014. En ese lapso 819 casos (796 pacientes) fueron tratados por masa renal. La edad media: 60.7 años (DE 13.1), 553 (69.5%) fueron hombres. El 29% (230) presentó obesidad (IMC ≥ 30). El diagnóstico fue incidental en 653 casos (79.7%). Un 48.8% (388 pacientes) presentó uno o más factores de riesgo, siendo el tabaquismo el más frecuente (34%). En 238 pacientes (29.9%) se presentó más de una comorbilidad. El 18% presentó creatinina preoperatoria ≥ a 1.3 mg/dl. El 45% de las lesiones fueron ≤ a 4 cm (cT1a). El 10.8% (86) de los pacientes presentaron metástasis al diagnóstico. El 93.5% de las lesiones fueron resecadas y el 6.5% fueron vigiladas activamente (no resecadas). Se utilizó la nefrectomía radical en el 51.5% y cirugía renal conservadora en el 48.5% de los pacientes operados. El abordaje laparoscópico fue utilizado en el 56.2%. El tumor renal se caracteriza en la actualidad por un diagnóstico incidental en estadios patológicos iniciales. La cirugía renal conservadora es la primera opción en casi la mitad de los pacientes. La vigilancia activa ha sido utilizada en un porcentaje mayor a lo comunicado en la literatura.