It appears that dose-escalated, moderately hypofractionated intensity-modulated radiation therapy (HIMRT) may have some advantages over conventionally fractionated IMRT (CIMRT) for treating men with localized prostate cancer. A study published in The Journal of Clinical Oncology suggests superior cancer control for men with localized prostate cancer who receive dose-escalated moderate HIMRT.1 In addition, it appears more convenient, because HIMRT cuts treatment duration.
Karen Hoffman, MD, University of Texas MD Anderson, Houston, and colleagues compared CIMRT (75.6 Gy in 1.8-Gy fractions during 8.4 weeks) with a dose-escalated moderate HIMRT regimen (72 Gy in 2.4-Gy fractions during 6 weeks) in 206 men. In this cohort, 72% had cT1 disease, 99% had a Gleason score of 6 or 7, 90% had a PSA level of 10 ng/mL or lower, and 24% were receiving androgen-deprivation therapy (ADT).
The researchers found that the men treated with HIMRT experienced fewer treatment failures than men treated with CIMRT (10 vs 21, respectively) with a median follow-up of 8.5 years. The 8-year failure rates were significantly different (10.7% for HIMRT vs 15.4% for CIMRT). The study demonstrated no differences in overall survival (OS) between the 2 treatment arms.
The researchers noted that there was a nonsignificant increase in late grade 2/3 gastrointestinal toxicity with HIMRT (12.6% vs 5.0%). However, the study showed that the number of men who developed toxicity was small, and all rectal bleeding resolved with treatment. The authors wrote that the risk of bleeding can be further reduced by minimizing the proportion of rectum exposed to high-dose radiation.
- Hoffman, KE, Voong KR, Levy LB, et al. Randomized trial of hypofractionated, dose-escalated, intensity-modulated radiation therapy (IMRT) versus conventionally fractionated IMRT for localized prostate cancer. J Clin Oncol. 2018;36(29):2943-2949.