Prognostic variables to predict cancer-related death in incidental renal tumours

To identify, in a large multicentre series of incidental renal tumours, the key factors that could predict cancer-related deaths, as such tumours have a better outcome than symptomatic tumours and selected patients are increasingly being included in watchful-waiting protocols.

Data from 3912 patients were extracted from three international kidney-cancer databases. Age, gender, Eastern Cooperative Oncology Group (ECOG) performance status (PS), Tumour-Node-Metastasis (TNM) stage, tumour size, Fuhrman grade, and final pathology were recorded. Benign tumours and malignant lesions with incomplete information were excluded from final analysis.

The mean (SD) age of the patients was 60.6 (12.2) years and the mean tumour size 5.5 (3.5) cm. Most tumours were malignant (90.2%) and of low stage (T1-T2, 71.7%) and low grade (G1-G2, 72.4%). There were nodal and distant metastases in 5.7% and 13% of the patients. In all, 525 (14.4%) patients died from cancer; in this group, tumours were >4 cm in 88.2% and had nodal or distant metastases in 20.2% and 49.3%, respectively. Multivariable analysis showed that tumour size >4 cm, ECOG PS >or=1, TNM stage and Fuhrman grade were independent predictors of cancer-related death.

A significant proportion of incidental renal tumours can lead to the death of the patient. Standard prognostic variables for renal cell carcinoma appear to remain valid for this subset of patients. A watchful-waiting strategy should not be recommended if the tumour diameter is >4 cm, if biopsy confirms high-grade tumours, or if there is an impaired ECOG PS, or computed tomography findings suggest the presence of advanced T stage.