‘Hypofractionated, intensity-modulated radiotherapy lowers breast cancer radiation therapy’s toxic risk’

Researchers at Severance Hospital have confirmed that hypofractionated, intensity-modulated radiotherapy can significantly reduce the side effects of radiation therapy after breast cancer surgery.

A Severance Hospital research team, led by Professor Kim Yong-bae, has confirmed that low segmentation intensity control radiotherapy reduces the risk of breast cancer radiation therapy toxicity.

The team, led by Professor Kim Yong-bae of the Department of Radiation Oncology, concluded after comparing the side effects of daily fractionated radiation therapy, low segmentation three-dimensional stereoscopic radiotherapy, and low segmentation intensity control radiotherapy.

According to Professor Kim, previous studies have shown that intensity-controlled radiation therapy has an advantage in dose distribution in radiation therapy design compared to the existing low segmentation three-dimensional stereoscopic radiotherapy.

“However, the clinical results of combining low-fraction radiation therapy with intensity-controlled radiation therapy for treating breast cancer patients was insufficient,” Kim said. “Notably, there was no reference standard due to the lack of clinical results on the side effects that Korean patients with relatively small breasts would experience while receiving radiation therapy.”

Therefore, the research team analyzed the factors affecting acute side effects such as changes in the breast skin such as radiation dermatitis and skin hardening. In addition, late side effects, including radiation pneumonia, lymphedema, hypothyroidism, and cardiac toxicity, depending on the radiation therapy technique on 5,749 patients who received radiation therapy for breast cancer at Severance Cancer Hospital from 2005 to 2017.

As a result, in patients that received 15 low segmentation intensity control radiotherapy, acute side effects and post-treatment side effects were significantly less than 28 patients that received daily fractionated radiation therapy and 15 patients that received low segmentation three-dimensional stereoscopic radiotherapy.

“The team confirmed that incidence of side effects was reduced by 89 percent in low segmentation intensity control radiotherapy compared to conventional daily fractionated radiation therapy,” Kim said. “In the same low-fragmented radiation therapy, the team confirmed that low segmentation intensity control radiotherapy reduced the incidence of side effects by about 55 percent compared to low segmentation three-dimensional stereoscopic radiotherapy.”

Professor Kim stressed that the study is meaningful as it comprehensively compared and evaluated radiation therapy based on divided dose and treatment technology.

“As a result, it has an important meaning as it suggested that 15 doses of low segmentation intensity control radiotherapy can effectively reduce the side effects associated with breast cancer radiation therapy toxicity,” Kim said.