Abstract
In contrast to other tumor sites, breast intensity-modulated radiation therapy (IMRT) has been evaluated for its ability to improve close homogeneity rather than to improve dose conformality. Three randomized clinical trials and a number of prospective series have shown that breast IMRT improved radiotherapy tolerance. The clinical outcomes have been consistent. All series and trials showed a reduction of acute dermatitis and moist desquamation which are acute side effects of radiation treatment, and also improvements in associated pain and quality of life outcomes. For women with large breasts, breast IMRT improved the cosmetic result and reduced permanent delayed side effects of the skin such as telangiectasia. It is currently unknown if breast IMRT reduces the risk of chronic breast or chest wall pain or has an impact on long-term quality, of life. There is consensus that either forward- or inverse-planned breast IMRT should be the standard in Canada, but there is a debate in the United States on the economic value of the clinical benefits. The cost of a course of radiation therapy doubles when the Medicare "inverse planning code" is used. This funding issue currently undermines the ability for the clinical community to achieve consensus on the role of IMRT to improve homogeneity during radiation therapy for breast cancer. Although highly likely, there is no direct evidence addressing whether breast IMRT will further improve breast hypofractionation tolerance. Women with large breasts, who are experiencing over 50% of moist desquamation even with the use of breast IMRT, may benefit. from the combination of a prone technique with breast IMRT to further improve treatment tolerance.