Intensity-modulated radiation therapy (IMRT) reduces toxicity without compromising efficacy, when compared with conventional radiation therapy (CRT), in patients with cervical and endometrial cancer, a phase 3 trial suggests.
Overall and disease-free survival outcomes were similar with IMRT and CRT at 3 years. However, CRT was associated with greater gastrointestinal and urinary toxicity. Researchers therefore concluded that IMRT should be the standard of care for these patients.
These results were published in the Journal of Clinical Oncology.
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This phase 3 trial (ClinicalTrials.gov Identifier: NCT01672892) included 279 patients with endometrial or cervical cancer who required postoperative pelvic radiation.
The patients were randomly assigned to CRT (n=149) or IMRT (n=130). The treating physician determined whether the RT dose was 45 Gy or 50.4 Gy and if concurrent cisplatin (40 mg/m2 once weekly) was administered.
The median follow-up was 37.8 months. Efficacy outcomes were similar between the groups.
The 3-year overall survival rate was 92.4% in the IMRT arm and 97.0% in the CRT arm (hazard ratio [HR], 0.76; 95% CI 0.32-1.79; P =.53). The 3-year disease-free survival rate was 85.5% and 80.8%, respectively (HR, 1.39; 95% CI, 0.82-2.35; P =.21).
The researchers assessed toxicity and quality of life using the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events, Expanded Prostate Cancer Index Composite (EPIC) bowel and urinary domains, and Functional Assessment of Cancer Therapy–General.
In the overall cohort, 97.1% of patients completed the EPIC questionnaire at baseline, 88.9% did so at week 3, 86.7% at week 5, 77.1% at 1 year, and 55.1% at 3 years.
The mean change in EPIC bowel summary score was similar at 1 year and 3 years in the IMRT and CRT groups. However, over time, IMRT resulted in a greater improvement in modeled bowel scores compared with CRT (P =.023).
At 1 year, the use of antidiarrheal medication was lower in the IMRT arm than in the CRT arm — 1.2% and 8.6%, respectively (P =.036). The proportion of patients who reported experiencing diarrhea frequently or almost constantly was 5.75% in the IMRT arm and 15.05% in the CRT arm (P =.042).
However, by 3 years, there was no significant difference in gastrointestinal toxicity between the IMRT and CRT arms.
At 1 year, there was no significant difference in the mean change in EPIC urinary summary score between the arms (P =.96). However, at 3 years, there was a significant improvement in the IMRT arm (P =.005).
“IMRT results in reduced patient-reported chronic diarrhea and urinary toxicity compared with CRT, with no difference in disease outcomes at 3 years,” the researchers wrote. “Clinical practice has now shifted such that IMRT is now commonly used to treat women with cervical or endometrial cancer receiving postoperative pelvic RT. The updated results of this trial fully support its continuous use in this setting and suggest that IMRT should now be considered the standard of care.”
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Yeung AR, Deshmukh S, Klopp Ah, et al. Intensity-modulated radiation therapyreduces patient-reported chronic toxicity compared with conventional pelvic radiation therapy: Updated results of a phase III trial. J Clin Oncol. Published online August 12, 2022. doi:10.1200/JCO.21.02831
