IMRT for Breast Cancer—Balancing Outcomes, Patient Selection, and Resource Utilization
Authors: Lisa A. Kachnic, Simon N. Powell
Journal: JNCI Journal of the National Cancer Institute (2011)

Over the past decade, there has been a rapid rise in the utilization of advanced radiation delivery technologies for the intended curative management of many solid cancers. For breast cancer, radiation practice patterns have shifted from conventional twodimensional therapy based on fluoroscopy and bony anatomy to a more refined three-dimensional approach utilizing computed tomography planning. Three-dimensional radiation provides the oncologist with precise information concerning the radiation dose to all areas of the affected breast, regional nodes, and adjacent normal tissues and therefore may offer reduced morbidity and improved long-term breast cosmesis, whereas maintaining local tumor control. The current question is whether further improvements in target dose coverage and normal organ sparing, both of which are provided by a more advanced form of radiation delivery called intensity-modulated radiation therapy (IMRT), produce a measurable improvement in treatment outcomes over three-dimensional radiation delivery. In this issue of the Journal, Smith et al. (1) report on the increased use of IMRT for the adjuvant therapy of breast cancer in the United States. Improvements in radiation-induced morbidity have been described in patients with head and neck and prostate cancers treated with IMRT (2,3). Small randomized studies in early-stage breast cancer also suggest that a reduction in acute toxicity can be achieved (4–6). However, in this era of rapidly evolving radiation technology, there is a concern that IMRT is being widely implemented without evidence-based knowledge of its effects on long-term efficacy and morbidity. Moreover, IMRT is associated with a substantially greater cost to the patient (or insurance company) because of the increased physician and physicist workload to generate IMRT plans and provide the necessary quality assurance for such plans. With the recent emphasis on cost-effective quality care in the Unites States, we must understand the potential benefits of this new technology and balance them with an appropriate selection of patients, as well as best use of resources, before IMRT can be adopted for the adjuvant management of breast or other cancers. Smith et al. (1) analyzed Surveillance Epidemiology and End Results–Medicare records of care and outcomes for 26 163 women aged 66 years or older who were treated with surgery and adjuvant radiation for nonmetastatic breast cancer between 2001 and 2005. They found that in 2001, there was a prevalence of IMRT use of 0.9%, which rose to 11.2% by 2005, reflecting a greater than 10-fold increase in use for a potentially large population of patients. Notably, the use of IMRT more than doubled the cost of radiation treatment, and the overall cost of treatment increased by more than 30% during this 5-year period. Unfortunately, these data do not provide insight into potential clinical scenarios in which IMRT may improve treatment results and perhaps justify its increased cost. Tumor characteristics were not strongly associated with an increased use of IMRT, suggesting that it was not being adopted to address a perceived medical concern. Even the higher prevalence of using IMRT for left-sided breast cancers (where there is concern over the radiation dose to the underlying lung and heart) was only 6.5%, as compared with 5.5% on the right. Notably, what we do learn from Smith et al (1) is that the largest increase in IMRT utilization is in regions where Medicare pays for it. As such, the major conclusion from the analysis is that IMRT is being adopted for the adjuvant management of localized breast cancer within areas of the Unites States where it is reimbursed. This conclusion would appear to confirm the suspicion of many, both within and outside of the healthcare industry, that medical