CCR Score Estimates Metastasis Risk for Prostate Cancer Treated With ADT, RT

Guidelines for the treatment of localized prostate cancer typically recommend the addition of androgen-deprivation therapy (ADT) to radiation therapy (RT) in certain patients, as it has been shown to improve metastasis-free survival at the population level.

Jonathan D. Tward, MD, PhD, and colleagues developed a new mathematical model to determine the benefit of adding ADT to RT as a function of the personalized clinical cell-cycle risk (CCR) score to ascertain 10-year metastasis risk.

An absolute risk reduction (ARR) model was developed using data from a retrospective cohort of 467 patients tested with the prostate cancer prognostic test Prolaris who received RT alone. The relative benefit of ADT added to RT to reduce distant metastasis was estimated at 41% on the basis of a meta-analysis of randomized trials.

The ARR and number needed to treat (NNT) were derived in 56,485 patients clinically tested with Prolaris between January 2020 and October 2022. Researchers predicted risk using a cause-specific Cox proportional hazards model. The CCR score was used to predict time to metastasis, and a CCR score of 2.112 represented the validated multimodal treatment (MMT) threshold.

Starting at almost 0 at low CCR scores, the ARR from ADT increased to 17.1% with the CCR at 3.690. The corresponding NNT was 6, showing that the addition of ADT to RT could prevent metastasis within 10 years for 1 of every 6 treated patients.

In the clinical cohort, the average ARR was 0.86% in patients under the MMT threshold (NNT=116) and 8.19% in patients above the MMT threshold (NNT=12). Ranges of ADT benefit were observed within the National Comprehensive Cancer Network risk categories.

This CCR score can provide a precise and personalized risk estimate of metastasis in patients with localized prostate cancer when considering treatment intensification.