In an individual patient data meta-analysis reported in The Lancet Oncology, Kishan et al found that isodose and dose-escalated moderately hypofractionated radiotherapy exhibited similar efficacy vs conventionally fractionated radiotherapy in patients with localized prostate cancer. They also reported that dose-escalated moderately hypofractionated radiotherapy was associated with increased bowel toxicity.
Study Details
A total of seven phase III trials comparing moderately hypofractionated radiotherapy with conventionally fractionated radiotherapy were eligible for inclusion in the analysis. Individual patient data were obtained from these studies, including 3,454 patients from three trials comparing conventionally fractionated radiotherapy with isodose moderately hypofractionated radiotherapy and 2,426 patients from four trials comparing conventionally fractionated radiotherapy with dose-escalated moderately hypofractionated radiotherapy.
Key Findings
No statistically significant differences were observed between patients who received isodose moderately hypofractionated radiotherapy vs conventionally fractionated radiotherapy in progression-free survival (hazard ratio [HR] = 0.92, 95% confidence interval [CI] = 0.81–1.05, P = .21) or overall survival (HR = 0.83, 95% CI = 0.68–1.01, P = .06). No statistically significant differences were observed between patients who received dose-escalated moderately hypofractionated radiotherapy vs conventionally fractionated radiotherapy for progression-free survival (HR = 0.94, 95% CI = 0.82–1.09, P =.43) or overall survival (HR = 0.92, 95% CI = 0.76–1.11, P = .39).
No increased risk of grade ≥ 2 genitourinary toxicity effects were identified for either isodose moderately hypofractionated radiotherapy (odds ratio [OR] = 1.16, 95% CI = 0.86–1.57, P = .32) or dose-escalated moderately hypofractionated radiotherapy (OR = 1.20, 95% CI = 0.95–1.51, P = .13) vs conventionally fractionated radiotherapy. The risk of grade ≥ 2 gastrointestinal toxicity was significantly higher with dose-escalated moderately hypofractionated radiotherapy (OR = 1.48, 95% CI = 1.14–1.92, P = .0035) but not isodose moderately hypofractionated radiotherapy (OR = 1.30, 95% CI = 0.59–2.87, P = .51) vs conventionally fractionated radiotherapy.
Isodose moderately hypofractionated radiotherapy was not associated with increased risk of urinary quality-of-life decrement (OR = 1.03, 95% CI = 0.51–2.09, P = .93) or bowel quality-of-life decrement (OR = 0.76, 95% CI = 0.40–1.43, P = .39) compared with conventionally fractionated radiotherapy. Dose-escalated moderately hypofractionated radiotherapy was associated with greater risk of bowel quality-of-life decrement (OR = 1.68, 95% CI = 1.07–2.61, P =.023) but not urinary quality-of-life decrement (OR = 1.57, 95% CI = 0.87–2.85, P = .13) compared with conventionally fractionated radiotherapy.
The investigators concluded “Isodose [moderately hypofractionated radiotherapy] and dose-escalated [moderately hypofractionated radiotherapy] both have similar efficacy compared with [conventionally fractionated radiotherapy], but dose-escalated [moderately hypofractionated radiotherapy] is associated with higher physician-scored and patient-reported bowel toxicity. Isodose regimens, eg, 60 Gy in 20 fractions, should be the standard [moderately hypofractionated radiotherapy] regimen for localized prostate cancer.”
Amar U. Kishan, MD, of the Department of Radiation Oncology at the University of California, Los Angeles, is the corresponding author for The Lancet Oncology article.
Disclosures: The investigators reported that there was no external funding for the study. For full disclosures of all study authors, visit thelancet.com.
