Stereotactic Body Radiotherapy for High-Risk Localized CARcinoma of the Prostate (SHARP) Consortium: Analysis of 344 Prospectively Treated Patients

Purpose To explore the efficacy and toxicity of stereotactic body radiotherapy (SBRT) in high risk prostate cancer (HRPCa) in a consortium of seven institutional phase II trials and prospective registries.

Methods and materials Individual patient data were pooled for 344 patients with a minimum follow-up of 24 months. Biochemical recurrence-free survival (BCRFS) and distant metastasis-free survival (DMFS) were estimated using a Kaplan-Meier framework. Fine and Gray competing risk and Cox proportional hazards regression models were developed to assess the association between time to BCR and time to distant metastasis and pre-specified variables of interest. Logistic regression models were developed to evaluate associations between acute and late grade ≥2 genitourinary (GU) and gastrointestinal (GI) and the following a priori specified variables: age, dose per fraction, ADT use, and nodal radiotherapy.

Results Median follow-up was 49.5 months. Seventy-two percent of patients received ADT, with a median duration of 9 months, and 19% received elective nodal radiotherapy. Estimated four-year BCRFS and DMFS rates were 81.7% (95% CI, 77.2-86.5%) and 89.1% (95% CI, 85.3%-93.1%). The crude incidences of late grade ≥3 genitourinary and gastrointestinal toxicity were 2.3% and 0.9%.

Conclusions These data support a favorable toxicity and efficacy profile for SBRT for HRPCa. Further prospective studies are needed to evaluate the optimal dose and target volume in the context of SBRT for HRPCa.

Ritchell van Dams, MD, MHS, Naomi Y. Jiang, MD, Donald B. Fuller, MD, Andrew Loblaw, MD, Tommy Jiang, BA, Alan J. Katz, MD, Sean P. Collins, MD, Nima Aghdam, MD, Simeng Suy, PhD, Kevin L. Stephans, MD, Ye Yuan, MD, PhD, Nicholas G. Nickols, MD, PhD, Vedang Murthy, MD, Tejshri P. Telkhade, MD, Patrick A. Kupelian, MD, Michael L. Steinberg, MD, Tahmineh Romero, MS, Amar U. Kishan, MD Source: Ritchell van Dams, Naomi Y. Jiang, Donald B. Fuller, et al. "Stereotactic Body Radiotherapy for High-Risk Localized CARcinoma of the Prostate (SHARP) Consortium: Analysis of 344 Prospectively Treated Patients." International Journal of Radiation Oncology. 2020. https://doi.org/10.1016/j.ijrobp.2021.01.016.


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