Renal mass biopsy rates increasing in kidney cancer

By Laura Cowen, medwireNews Reporter

Rates of renal mass biopsy (RMB) have been historically low in patients with kidney cancer, but are steadily rising, shows an analysis of Medicare data.

Between 1992 and 2007, 24,702 patients from the Surveillance, Epidemiology, and End Results-Medicare dataset were diagnosed with kidney cancer. Of these, 5112 (20.7%) received RMB, with the highest rate observed in the final year of the study when 30.3% of patients underwent the procedure.

The rise in RMB use in the latter years of the of the study was mainly driven by a rapid increase – from around 30% in 2005 to around 55% in 2007 – among patients with metastatic disease at presentation, report John Leppert (University of Stanford, California, USA) and colleagues. They note that this increase coincided with the introduction of new Food and Drug Administration-approved targeted therapeutics.

Patients undergoing ablation were most likely to receive RMB, with a rate of 61.5% observed during the study period. This is probably because ablation procedures involve placement of a needle into the tumour making it logical to perform RMB at the same time, say the researchers. “In fact, guidelines suggest that RMB should be performed in all patients undergoing ablative therapy for this reason,” they write in Urology.

Although the rate of RMB was high among patients undergoing ablation, Leppert and team point out that 39.5% did not receive the procedure. They say that because few patients have reliable confirmation of pathological change after ablation, “care providers should recognize uncertainties when proceeding with ablation in the absence of RMB.”

Patients treated with systemic therapy were more likely to undergo RMB than those who underwent partial or radical nephrectomy, with respective rates of 50.4%, 20.4% and 17.3%.

Multivariate analyses adjusted for age at diagnosis, comorbidity and tumour size showed that younger age, male gender, Black and Hispanic race/ethnicity, smaller tumours (<7 cm) and comorbidity (Charlson Index score ≥1) were all associated with increased odds of receipt of RMB.

In an accompanying editorial comment, Marc Smaldone and Robert Uzzo from the Fox Chase Cancer Centre in Pennsylvania, Philadelphia, USA point out that restricting the study to patients with confirmed kidney cancer is a considerable limitation because it excludes patients with benign tumours and inadequate biopsies, making it difficult to contextualise the findings.

Leppert and co-authors agree that their study has its limitations, but hope that it will “set the stage for future investigation of the effectiveness of RMB and strategies for implementing RMB in the evaluation of patients with a renal mass.”

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