Dr Nawfal on Radiological Tumor Burden as an Independent Prognostic Factor of Survival in mccRCC

Rashad Nawfal, MD, postdoctoral research fellow at Dana-Farber Cancer Institute, discusses the efficacy of radiological tumor burden as an independent prognostic factor for survival in patients with metastatic clear cell renal cell carcinoma (mccRCC) treated with first-line immuno-oncology (IO)-based regimens.

Data were reviewed from 183 patients with mccRCC treated at Dana-Farber Cancer Institute between August 2014 and October 2023. These patients received at least one dose of an IO-based regimen, including combinations of dual immunotherapy agents or an IO agent plus a VEGF inhibitor. Of the 150 patients included in the study, 9% had favorable risk, 51% had intermediate risk, and 20% had poor risk by International Metastatic RCC Database Consortium (IMDC) criteria. Additionally, 73% of patients had undergone nephrectomy prior to first-line therapy initiation, and 41% had metastases in the brain, bone, or liver.

Results from the abstract were presented at the 2024 Kidney Cancer Research Summit with median follow-up of 44.8 months. The findings demonstrated that baseline radiological tumor burden is an independent prognostic factor for overall survival (OS) in this population, as every 1 cm increase in baseline radiological tumor burden was associated with a 5% increase in OS events (HR, 1.05; 95% CI, 1.03-1.08; P < .0001). This finding remained significant after multivariable analysis (HR, 1.04; 95% CI, 1.00-1.08; P = .03), which accounted for variables such as previous nephrectomy, IMDC risk group, and the presence of metastases in the brain, bone, or liver prior to frontline therapy.

The study also categorized baseline radiological tumor burden by tertiles: tertile 1 (0-7.5 cm), tertile 2 (7.6-15.3 cm), and tertile 3 (15.4-47.7 cm). The 4-year OS estimates were 84% (95% CI, 74%-97%) for the first tertile, 60% (95% CI, 45%-81%) for the second tertile, and 43% (95% CI, 29%-66%) for the third tertile (log-rank P < .0001). Nawfal also notes that although baseline radiological tumor burden was a significant predictor of OS, it did not show a significant association with time to treatment failure (TTF) or time to next treatment (TTNT) on both univariable and multivariable analyses.

Overall, the results underscore the utility of baseline radiological tumor burden as a prognostic marker for OS in patients with mccRCC treated with IO-based regimens, Nawfal says. These findings may support integrating radiological tumor burden assessments into routine clinical practice to improve prognostic accuracy and guide treatment decisions for better patient outcomes.