LOS ANGELES Use of intensity-modulated radiation therapy rather than conventional radiation significantly reduced the severity and duration of acute dermatitis in a review of consecutive cancer patients who underwent whole breast radiation after breast-conserving surgery.
All but 3% of 804 women experienced some acute dermatitis during the treatments, which typically lasted 7-8 weeks, Dr. Gary M. Freedman of Fox Chase Cancer Center in Philadelphia reported at the annual meeting of the American Society for Therapeutic Radiation and Oncology.
Of all patients who were treated from 2001 to 2006 in the multivariate analysis that considered week of treatment and breast size, 61% experienced grade 2 toxicity (with 0 being no toxicity and 5 being death), according to the National Cancer Institute Common Toxicity Criteria scale for acute dermatitis. For these women, skin reactions included moderate to brisk erythema, patchy moist desquamation (mostly confined to skinfolds and creases), and moderate edema.
Of all the women who underwent radiation therapy, 34% had grade 1 skin toxicity, a category comprising faint erythema or dry desquamation. For 2%, radiation treatments resulted in grade 3 toxicity, by which minor trauma or abrasion could cause the breast to bleed and moist desquamation went beyond the skinfolds and creases.
The investigators then stratified the women and found acute dermatitis tended to be milder with the newer intensity-modulated radiation therapy (IMRT). The advantage was seen every week that treatment was given in women with all breast sizes.
Nearly half, 48%, of the 399 women undergoing IMRT had nothing worse than grade 1 dermatitis, compared with 25% of 405 women given radiation with conventional wedged photon tangents. Conversely, three-fourths of the women treated with conventional radiation, but only 52% of the IMRT cohort, experienced grade 2 and 3 dermatitis, a statistically significant difference.
The duration of grade 2 and 3 dermatitis also was shorter with IMRT. Women treated with this technique spent only 18% of their treatment weeks in this combined category, as opposed to 71% of the time for women given conventional radiation.
IMRT conveys "less toxicity to the skin during treatment and less risk of peeling of the skin," Dr. Freedman said in an interview. Longer follow-up is needed before investigators can show better cosmetic results 5 years after treatment. However, "we feel that is going to translate long term into better cosmetic results," he said.
At Fox Chase, radiation oncologists transitioned to IMRT around 2004, and use it in most cases, "insurance permitting," according to Dr. Freedman. Some major carriers have balked at the higher cost of IMRT, which employs more radiation beams and requires more planning. Where they don't disallow it outright, they may pay for IMRT only in cases of left-sided breast cancer where there is a risk of radiation damaging the heart.
"The majority of women in this country are still being treated with conventional radiation," he said, questioning the fairness of insurance industry practices limiting access to IMRT for women with breast cancer.
IMRT is favored as a way of reducing radiation doses to the bladder and rectum in men with prostate cancer, Dr. Freedman maintained. "The first thing to come through was prostate cancer, and insurance companies welcomed that with open arms," he said. "I feel breast cancer is being held to a higher standard. The same is true for head and neck cancer."