Clinician- and Patient-Reported Outcomes of Stereotactic Ablative Radiation Therapy for High-Risk Prostate Cancer.

Purpose: This study evaluated the feasibility and tolerability of SABR in patients with high- and very-high-risk prostate cancer.

Methods and materials: A prospective study included patients with high-risk and N1 prostate cancer. SABR was delivered as 40 Gy in 8 Gy fractions, with optional elective nodal irradiation (26 Gy in 5.2 Gy fractions) and a 40 Gy nodal boost for N1 disease. The treatment protocol involved 24 to 36 months of androgen deprivation therapy, premedication with alpha-1 receptor antagonists, and dexamethasone (4 mg on treatment days). Adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events v5.0, while quality of life was assessed using the EORTC QLQ-C30 and QLQ-PR25 questionnaires at the final check-up.

Results: The study included 96 patients (median age 77.2 years) with a median follow-up of 29.8 months. Elective nodal radiation therapy was delivered to 66.7% of patients, and 16.8% received a nodal boost. Acute grade 2 (G2) genitourinary and gastrointestinal (GI) events occurred in 5.2% and 7.3% of patients, respectively, with no grade ≥3 acute events. Late grade ≥2 genitourinary and GI events were observed in 7.8% and 15.7% of patients, respectively, including 1 grade 4 GI event. Common late symptoms included nocturia and rectal bleeding. Most patients (86.5%) reported no or minor difficulties posttreatment, though challenges with sexual activity, nocturia, and incontinence were noted. Physicians underestimated urgency and nocturia and overestimated rectal bleeding.

Conclusions: SABR delivering 40 Gy in 5 fractions is feasible and well-tolerated for high-risk prostate cancer, with minimal additional toxicity from elective nodal irradiation and a boost to N1 disease. These findings support SABR as an effective treatment, warranting further long-term studies.