Clinical predictors of a positive test result in patients undergoing genetic evaluation for a hereditary kidney cancer syndrome.

INTRODUCTION

Guidelines are available to assist providers in identifying patients with renal cell carcinoma (RCC) that may benefit from genetic counselling, however, the evidence for these recommendations lacks support from the literature and controversy remains as to who should be referred. We aimed to delineate risk factors associated with a positive genetic test in a real-life cohort of patients with RCC referred to a regional medical genetics unit for evaluation of a hereditary kidney cancer syndrome.

METHODS

Patients with a diagnosis of RCC referred to Maritime Medical Genetics Service (Nova Scotia, Canada) from 2006-2017 were reviewed using retrospective data. The primary outcome was identification of clinical features that were associated with a positive test result. Logistic regression models were used for analysis.

RESULTS

A total of 135 patients were referred to medical genetics for evaluation; 102 patients were evaluated, 75 underwent testing, and 74 were included in the final analysis. Five patients tested positive: three Birt-Hogg-Dubé, one Cowden syndrome, and one Von Hippel-Lindau. Presence of dermatological lesions (specifically fibrofolliculomas) and more than two high-risk features were the only predictors of a positive test result.

CONCLUSIONS

The presence of dermatological lesions and more than two high-risk features are the only predictors of a positive test result in patients with a suspected hereditary kidney cancer syndrome. These findings are not reflected in current guidelines, and the clinical implementation of our results may improve the identification of high-risk patients for genetic counselling.