Stereotactic radiation therapy has been investigated predominantly in patients with low-intermediate-risk disease. We conducted a clinical trial of stereotactic hypofractionated radiation therapy delivered in once-weekly fractions on patients with all-risk non-metastatic disease to test feasibility, acute toxicities and patient-reported outcomes.

In this phase I/II study, 30 patients with prostatic adenocarcinoma, any Gleason score, T1-4N0 and prostate-specific antigen ≤60 ng/ml were treated with volumetric intensity modulated arc radiation therapy to a dose of 35 Gy in five fractions delivered once weekly. Patients with high-risk disease also received elective nodal irradiation to a dose of 25 Gy in five fractions simultaneously. Androgen deprivation was offered to intermediate- and high-risk patients. The primary outcome was acute toxicity. Secondary outcome measures included biochemical control and late toxicity. Patient-reported outcomes were measured using the International Prostate Symptom Score and European Organization for Research and Treatment of Cancer (EORTC) Quality-of-Life Questionnaire (QLQ).

All 30 patients completed treatment per-protocol. Most patients had T3 (60%) and Gleason 7 (50%) tumours. The median prostate-specific antigen was 17 ng/ml. High-risk disease was present in 20 patients (66.7%). There was a low incidence of acute toxicities (grade 2 + urinary 3.3%, grade 2 rectal 0%). Within the EORTC QLQ framework, only the urinary symptom score showed a clinically meaningful worsening from a mean of 20/100 at baseline to 34/100 at the end of treatment (P < 0.001), but reduced to 24/100 at 6 months (P = 0.08). With a median follow-up of 41.5 months, two patients each reported grade 2 late urinary and rectal toxicity. The 3- and 4-year biochemical control rates were 96.7 and 87.9%, respectively.

In a cohort of mainly high-risk cancers, stereotactic once-weekly radiation therapy was easy to implement and well tolerated, with a low incidence of acute and late toxicity and excellent biochemical control.

Clinical oncology (Royal College of Radiologists (Great Britain)). 2019 Sep 21 [Epub ahead of print]

I Mallick, M Arunsingh, S Chakraborty, B Arun, S Prasath, P Roy, D Dabkara, R Achari, S Chatterjee, S Gupta

Department of Radiation Oncology, Tata Medical Center, Kolkata, India. Electronic address: ., Department of Radiation Oncology, Tata Medical Center, Kolkata, India., Department of Pathology, Tata Medical Center, Kolkata, India., Department of Medical Oncology, Tata Medical Center, Kolkata, India., Department of Urological Surgery, Tata Medical Center, Kolkata, India.