Prognostic role of tumour multifocality in renal cell carcinoma.

Study Type - Therapy (multi-centre cohort) Level of Evidence 3b What's known on the subject? and What does the study add? In RCC about 5\% of the patients presented multifocal disease. Prevalence of tumour multifocality was associated with a higher percentage of symptomatic RCC, higher pathological TNM stages, higher tumour grade and higher prevalence of tumour necrosis. Although in univariable analysis multifocal tumours had lower probability of CSS, tumour multifocality did not retain an independent predictive role in multivariable analysis. Patient age at surgery, gender, mode of presentation, pathological N stage and presence of metastases were independent predictors of CSS in multivariable analyses. OBJECTIVE: •  To evaluate the prevalence and the prognostic role of multifocality in a large multi-institutional series of patients who underwent radical or partial nephrectomy for renal cell carcinoma (RCC). METHODS: •  We retrospectively collected the data of 5378 patients who were surgically treated for RCC in 16 academic centres involved in the Surveillance and Treatment Update Renal Neoplasms (SATURN) project. •  Univariable and multivariable Cox regression models addressed time to cancer-specific survival (CSS) after surgery. RESULTS: •  Tumour multifocality was identified in 249 patients (5\%). The median follow-up of the whole cohort was 42 months. At last follow-up, 786 (14.6\%) were dead of cancer and 336 (6.2\%) had experienced non-cancer-related death. •  The 5- and 10-year CSS estimates were 84.1\% and 77.3\%, respectively, in patients with monofocal RCC, compared with 71.1\% and 63.6\%, respectively, in patients with multifocal disease (P < 0.001). •  In univariable Cox regression analysis, tumour multifocality was significantly associated with CSS (hazard ratio [HR]= 1.83; P < 0.001). •  On multivariate Cox regression analysis adjusted for the effects of other covariates, tumour multifocality did not retain an independent predictive value (HR = 1.24; P= 0.291). CONCLUSIONS: •  In the present multi-institutional collaboration, about 5\% of the patients presented multifocal RCC. •  The presence of multifocal cancer was associated with some unfavourable clinical and pathological features. •  Although in univariable analysis multifocal tumours had lower CSS probabilities, tumour multifocality did not retain an independent predictive role in multivariable analysis, once adjusted for the effect of the other clinical and pathological covariates.