Real-life use of diagnostic biopsies before treatment of kidney cancer: results from a Norwegian population-based study

<p><b>Objective:</b> Interest in renal mass biopsies (RMBs) has increased in recent years. However, most publications are low-volume and/or single-center studies, so their generalizability is questionable. The aim of this study was to describe population-based, real-life use of diagnostic RMBs for localized and advanced kidney cancer (KC).</p> <p><b>Materials and methods:</b> All KC patients diagnosed during 2008–2013 extracted from the database at the Cancer Registry of Norway were included. Relationships with outcome were analyzed using multivariate logistic regression and competing risks analyses.</p> <p><b>Results:</b> Of patients treated radically for localized KC, a pretreatment RMB was used in 8.4%. For similar patients treated by observation only, the rate increased from 29.3% to 60.7% during the study period. Tumor size ≤4 cm, another malignancy, multiple tumors, old age (≥ 80 years) and second study half were independent RMB predictors. Competing risks analysis showed that among radically treated patients with localized KC, those who had undergone an RMB had a higher risk of dying of other diseases. In patients with advanced KC, biopsy was used in 54.5%, and is increasing. Study limitations include a lack of data on benign tumors, comorbidity and performance status.</p> <p><b>Conclusions:</b> For localized KC, the use of RMBs in Norway is in line with current guidelines. Because real-world data on RMB use are scarce, this study is useful for benchmarking in future studies. Furthermore, the study shows that fewer patients with advanced KC are treated without histopathological verification, and biopsies seem to have an increasing role in tailoring treatment.</p