Pathological High-risk Renal Cell Carcinoma: Trends in Clinical Characteristics Over 25 Years

The incidence of renal cell carcinoma (RCC) has been increasing mainly due to the increase in the incidental detection of small renal masses. The aim of this study was to verify whether the trend towards early diagnosis changed the clinical characteristics of pathologically-defined high-risk RCC patients over the last decades.

A total of 741 patients with pathologically-confirmed high-risk RCC (pT1-4, and/or pN1 and/or Fuhrman grade 3-4 and/or all M1 patients) treated with radical (RN) or partial nephrectomy (PN) at a single tertiary referral center between 1987 and 2011 were included in the study. The temporal trends of pre-operative clinical and tumor characteristics were assessed relying on the lowess smoother weighted function with corresponding 95% confidence interval. Estimated annual percentage changes (EAPC) were evaluated using a log linear regression model.

The median age of patients increased from 57.5 to 67.3 years between 1987 and 2011 (EAPC 4.9%, p=0.002). Body mass index and gender rates remained stable during the study period. A constant trend towards patients with one or more comorbidity was observed. Moreover, the proportion of asymptomatic patients at diagnosis and of clinical T1 increased by 41.1 and 19.8%, respectively (all p≤0.007). The clinical tumor size dropped from 8.4 to 6.2 cm (EAPC -1.2%, p=0.001). This trend was accompanied by a clinically-relevant increase by 15.3% in the rate of patients without clinical metastases (p=0.07). Conversely, the rate of clinical lymphadenopathies remained stable over time. Finally, the rate of PNs performed increased by 23.3% (p<0.001).

Over the years, pathologically-confirmed high-risk RCC patients are older, mostly asymptomatic, with smaller cancers, with a higher rate of tumors localized to the kidney and with a decreased rate of metastatic disease at diagnosis. These trends can explain the increasing number of PNs performed despite the presence of a high-risk cancer profile.