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Sandy Srinivas, MD
Sandy Srinivas, MD
Posted: Friday, October 28, 2022
According to research presented in Radiation Oncology, external-beam radiotherapy dose escalation capped at 82 Gy may be safe and feasible, with few adverse side effects for up to 37.5 months after treatment in patients with localized prostate cancer when performed with perirectal hydrogel spacers in place. Significantly increased rectal toxicity has previously been associated with dose escalation above 80 Gy as prostate cancer treatment.
“To our knowledge, this is the first study to evaluate outcomes of prostate external-beam radiotherapy to an escalated dose of at least 82 Gy (2 Gy per fraction) following insertion of a perirectal hydrogel spacer,” noted Andrew W. See, MD, of the Icon Cancer Centre, East Melbourne, Australia, and colleagues.
The phase II trial included 70 men with localized prostate cancer who received intensity-modulated radiotherapy after undergoing the insertion of perirectal hydrogel spacers. The standard treatment course, prescribed at 78 Gy, was adjustable in increments of 2 Gy with a maximum dose of 82 Gy. A total of 64 patients (91.4%) received the maximum treatment course of 82 Gy. At a median follow-up of 37.4 months, no patient had experienced grade 3 gastrointestinal adverse effects, whereas two patients (2.9%) had experienced grade 3 genitourinary adverse events related to the insertion process for the hydrogel spacer.
Quality of life remained consistent overall, with only slight and impermanent declines observed. At 13.5-month and 37.5-month follow-ups, no clinically or statistically significant decrease in quality of life was noted. No gastrointestinal toxicity of grade 2 or higher as defined by the Radiation Therapy Oncology Group was observed, and no gastrointestinal toxicity of any grade was noted at a follow-up of 37.5 months. However, nine patients (12.9%) experienced biochemical failure within 37.5 months of receiving treatment.
“Future studies should prospectively assess whether long-term oncological and functional outcomes of dose escalation to [equivalent dose in 2-Gy fractions] > 80 Gy with use of a hydrogel spacer results in a sustainable widening of the therapeutic ratio for this cohort of patients...,” the authors concluded.
Disclosure: The study authors reported no conflicts of interest.
