Microvascular and lymphovascular tumour invasion are associated with poor prognosis and metastatic spread in renal cell carcinoma: a validation study in clinical practice

ObjectiveTo validate microvascular (MVI) and lymphovascular (LVI) invasion as prognostic factors in patients with renal cell carcinoma (RCC). Patients and MethodsData of patients with RCC who underwent radical or nephron-sparing surgery were prospectively collected from three academic centres. The occurrence of MVI and LVI was determined with standard staining protocols by experienced pathologists at the time of diagnosis. The association of MVI and LVI with clinicopathological data, metastatic spread, and cancer-specific survival (CSS) were evaluated with Fisher's exact tests, binary logistic regression analyses, and univariable and multivariable Cox proportional hazard regression models. ResultsMVI was present in 201 of 747 patients (26.9%) and was associated with advanced Tumour-Node-Metastasis (TNM) stages, high Fuhrman grades, and sarcomatoid features (all P< 0.001). MVI was associated with a higher rate of metastatic spread. LVI was present in 32 of 573 patients (5.5%) and was associated with advanced TNM stages, high Fuhrman grade, and sarcomatoid features (all P < 0.001). Two-thirds of LVI-positive patients died (P < 0.001). Both LVI and MVI were significantly associated with CSS in all patients, clear cell RCC (ccRCC), and localised RCC in univariable analysis (all P < 0.001). On multivariable analysis, presence of MVI was identified as an independent prognostic factor (hazard ratio 2.09; P = 0.001). Moreover, MVI [odds ratio (OR) 2.7; P = 0.001] and not macrovascular invasion (P = 0.895) was an independent predictor of sychronuous metastatic spread. LVI was the strongest factor associated with sychronous metastatic spread (OR 4.73, 95% confidence interval 1.84-12.14; P = 0.001) in all patients and in the subgroup of patients with ccRCC (P = 0.001). ConclusionsThe present study validated LVI and MVI as prognostic factors for poor outcome in RCC. These findings endorse an evaluation of both variables in the clinical routine setting to facilitate survival prognostication in follow-up protocols and for assignment to adjuvant treatment trials.