Hypofractionation should be the standard of care for breast cancer radiotherapy
*Sanjiv Sharma Department Of Radiation Oncology, India
*Corresponding Author: Sanjiv Sharma
Department Of Radiation Oncology, India Email:email@example.com
Published on: 2018-12-20
Clinical adoption of hypofractionation for breast cancer radiotherapy has been sub-optimal, despite sound rationale and robust level I evidence. Radiobiological modelling, primarily spearheaded by the development of Linear Quadratic model, has shown that the biological effect of radiation is a function of total dose and fraction size, and that the inherent radiation sensitivity or α ⁄ β ratio of the tissue in question will modify the effect of fraction size. This model suggests that if the α ⁄ β ratio of the tumor is same or less than that of relevant normal tissue, then a larger dose per fraction with a modest decrease in total dose may be equally or potentially more effective than the conventionally fractionated radiotherapy.
Clinical advantages of hypofractionation are convenience, improved access to care, less cost to patient as well as the health care system and reduced resource utilization along with less skin toxicity due to lower total doses. Robust evidence has been generated for hypofractionation by four large wells conducted clinical trials[1-6], summarized here in Tables 1 & 2. Hypofractionation conclusively was shown to be equivalent to conventional fractionation regarding various parameters of efficacy, cosmesis and toxicity. All treatment effects were independent of any of the patient, tumor or treatment related factors, like age, breast size, type of surgery, axillary nodal status, tumour grade, adjuvant chemotherapy use, tumour bed boost, and lymphatic radiotherapy. The trials conclusively showed that the fears of serious toxicity viz. ischaemic heart disease, rib fracture, brachial plexopathy, symptomatic lung fibrosis and damage to the normal breast tissues causing poor cosmesis, to be misplaced, and these should no longer be barriers to the wide spread adoption of this important clinical advance of the last decade. Additional reassurance is provided by the radiobiological modelling which suggests that hypofractionation tends to be less damaging to normal tissues like heart, lungs, normal breast tissue and brachial plexus, even under extreme assumptions about their fractionation sensitivity .