BOSTON-Women with cervical and endometrial cancer experience fewer side effects and report better quality of life when treated with intensity-modulated radiation therapy (IMRT) rather than radiation therapy (RT), according to an international, multi-center clinical trial (Radiat Oncol 2016;96;2 Supplement:S3).
Patient-reported gastrointestinal (GI) and genitourinary (GU) side effects were significantly fewer and patient quality of life (QOL) better with IMRT, investigators reported at the 58th Annual Meeting of the American Society for Radiation Oncology.
Study Methodology, Findings
The trial involved 278 women with cervical or endometrial cancer who received pelvic RT postoperatively in the U.S., Canada, Japan, and Korea. The 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), as well as disease site. The women were then randomly assigned to receive IMRT or RT.
Multiple patient questionnaires were given for acute GI and GU toxicities and QOL. 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 5 weeks following RT start using two-way t-tests.
Patients in the IMRT arm experienced significantly fewer bowel-related toxicities than patients who received standard RT, as indicated by smaller average declines in their EPIC bowel domain scores (-18.6 vs. -23.6, p = 0.048). Analysis of subscales within the EPIC determined that IMRT patients experienced less severe declines in bowel function but not bowel bother.
IMRT patients also experienced fewer high-level adverse events following treatment, including less diarrhea (frequency: 33.7 vs. 51.9%, p = 0.01) and fecal incontinence (frequency: 1.1 vs. 9.3, p = 0.01). Moreover, roughly one in five women in the standard RT group (20.4%) reported taking four or more anti-diarrheal medications daily, compared to 7.8 percent of women in the IMRT group (p = 0.04).
Urinary side effects at 5 weeks from treatment start were less prevalent among patients who received IMRT, as indicated by significantly smaller declines in average EPIC urinary domain scores for the IMRT arm (-5.6 vs. -10.4, p = 0.03). Furthermore, IMRT regime negatively impacted patients' QOL less substantially than the conventional RT regime did. FACT-Cx trial outcome index scores demonstrated less decline in health-related QOL following IMRT compared to standard RT (-8.8 vs. -12.8, p = 0.06). Patients treated with IMRT had less change in physical well-being (-4.2 vs. -6.1, p = 0.03) and addition concerns (-2.7 vs. -4.9, p = 0.01).
IMRT vs. RT
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.
"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.
"Many radiation oncologists already use IMRT for women undergoing pelvic radiation, but this research provides data that using IMRT, which is a more resource intensive treatment, makes a real difference to patients receiving radiation therapy to the pelvic area," she concluded. "When performed by an experienced radiation oncology team, IMRT reduces the risk of short-term bowel and bladder side effects for patients with endometrial and cervical cancer."
Kurt Samson is a contributing writer.