BOSTON, September 26, 2016 -- Patients with cervical and endometrial cancer have fewer gastrointestinal and genitourinary side effects and experience better quality of life when treated with intensity-modulated radiation therapy (IMRT) than with conventional radiation therapy (RT), according to research presented today at the 58th Annual Meeting of the American Society for Radiation Oncology (ASTRO). Women receiving IMRT reported significantly fewer bowel and bladder problems than those receiving conventional radiation treatment.

Many women diagnosed with cervical or endometrial cancer receive RT following surgery to remove their tumors, but questions remain as to which form of pelvic RT delivery can most effectively eliminate the tumor while minimizing the impact of radiation on surrounding healthy tissue. This multi-center, international study assessed this impact by evaluating patient-reported acute toxicities in the gastrointestinal (GI) and genitourinary (GU) systems following IMRT, an advanced form of external beam RT that delivers precise radiation doses highly tailored to patients' individual tumors, versus standard four-field RT.

"The way that radiation therapy is performed has a major impact on the risk of side effects from treatment," said Ann H. Klopp, MD, PhD, lead author of the study and an associate professor in the department of radiation oncology at the University of Texas MD Anderson Cancer Center in Houston. "We know that IMRT reduces the amount of normal tissue irradiated, so we suspected that it would have fewer side effects. This was one of the first studies, however, to rigorously ask this question using patient questionnaires to ensure that the lower doses resulted in meaningful differences in patients' experiences during treatment."
A total of 278 patients with cervical or endometrial cancer who received pelvic RT post-operatively at cancer centers in the U.S., Canada, Japan and Korea were evaluated to determine if pelvic IMRT for cervical and endometrial cancer resulted in fewer patient-reported GI and GU side effects and improved patients' QOL. Patients were stratified based upon RT dose (45 Gy or 50.4 Gy), use of chemotherapy (no chemotherapy or five cycles of weekly cisplatin at 40 mg/m2), and disease site. The patients were then randomly assigned to receive standard RT or IMRT.

Acute GI and GU toxicities and QOL were measured via multiple patient questionnaires. Instruments included the Expanded Prostate Cancer Index Composite (EPIC) to measure bowel and urinary toxicities, the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) to assess GI- and GU-related adverse events (e.g., diarrhea), and the Functional Assessment of Cancer Therapy – General with cervix subscale (FACT-Cx) to track health-related QOL. Researchers compared changes in average scores on these instruments from baseline to five weeks following RT start using two-way t-tests.

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