Clinico-pathological analysis of renal cell carcinoma demonstrates decreasing tumour grade over a 17-year period

Abstract

Introduction: Renal cell carcinoma (RCC) represents about 3% of adult malignancies in Ireland. Worldwide there is a reported increasing incidence and recent studies report a stage migration towards smaller tumours. We assess the clinico-pathological features and survival of patients with RCC in a surgically treated cohort. Methods: A retrospective analysis of all nephrectomies carried out between 1995 and 2012 was carried out in an Irish tertiary referral university hospital. Data recorded included patient demographics, size of tumour, tumour-node-metastasis (TNM) classification, operative details and final pathology. The data were divided into 3 equal consecutive time periods for comparison purposes: Group 1 (1995-2000), Group 2 (2001-2006) and Group 3 (2007-2012). Survival data were verified with the National Cancer Registry of Ireland. Results: In total, 507 patients underwent nephrectomies in the study period. The median tumour size was 5.8 cm (range: 1.2- 20 cm) and there was no statistical reduction in size observed over time (p = 0.477). A total of 142 (28%) RCCs were classified as pT1a, 111 (21.9%) were pT1b, 67 (13.2%) were pT2, 103 (20.3%) were pT3a, 75 (14.8%) were pT3b and 9 (1.8%) were pT4. There was no statistical T-stage migration observed (p = 0.213). There was a significant grade reduction over time (p = 0.017). There was significant differences noted in overall survival between the T-stages (p < 0.001), nuclear grades (p < 0.001) and histological subtypes (p = 0.022). Conclusion: There was a rising incidence in the number of nephrectomies over the study period. Despite previous reports, a stage migration was not evident; however, a grade reduction was apparent in this Irish surgical series. We can demonstrate that tumour stage, nuclear grade and histological subtype are significant prognosticators of relative survival in RCC.