Science Spotlight

Understanding radiation therapy practices

From the Roth Group, Division of Public Health Sciences

As the incidence of many types of cancer increases, associated health care costs are also climbing and adding substantial financial burden to patients. In efforts to control costs, there is now greater emphasis on the value of medical care. Understanding the benefit versus harm of cancer treatments, along with associated costs, may help control high medical expenses. These efforts are referred to as Choosing Wisely (CW) recommendations. Within the field of Radiation Oncology, the use of intensity modulated radiation therapy (IMRT) has been available in recent decades. Although this is an advanced method for delivery of radiation therapy, debate exists on whether there are long-term benefits associated with IMRT compared to conventional radiotherapy (cRT) for specific cancers. In IMRT, a computational model of the tumor based on CT scans is used to deliver doses of radiation to the tumor while sparing healthy organs. A formal CW recommendation advising against the standard use of IMRT for whole breast radiation was released by the American Society for Radiation Oncology in 2013. Dr. Joshua Roth, member in the Division of Public Health Sciences, and collaborators conducted a study to determine the use of IMRT in early-stage breast cancer patients in the period preceding the 2013 Choosing Wisely recommendations. Results were recently published in the journal PLoS ONE.

In addition to assessing the use of IMRT, the authors aimed to determine whether medical expenditures associated with breast cancer treatment were affected by the use of IMRT. The authors utilized data in the Surveillance, Epidemiology, and End Results (SEER) registry, a national registry that began in 1973 and collects information on diagnosed cancer cases in several states and regions in the United States. When linked to a database of Medicare claims, the SEER registry also provides information on treatment-associated healthcare costs during the time a patient is eligible for Medicare. Twelve of the SEER registries were included in the study: Connecticut, Detroit, California, Georgia, Hawaii, Iowa, Kentucky, Louisiana, New Jersey, New Mexico, Seattle, and Utah. SEER data from 2008 – 2011 and Medicare claims data from 2007 – 2012 were used for the analyses. Eligibility criteria for inclusion in the study included early stage (I and II) cancer, at least 66 years of age, and continuous Medicare coverage during the year preceding diagnosis to one-year post-diagnosis. Approximately 13,000 patients met the criteria and were included in the study. The treatment regimen for all patients in the study included lumpectomy within six months of diagnosis followed by radiation therapy in the subsequent six months.

Graphical representation of proportion of early stage breast cancer patients included in twelve SEER registries receiving intensity modulated radiation therapy (IMRT) after lumpectomy.
Proportion of early stage breast cancer patients included in twelve SEER registries receiving intensity modulated radiation therapy (IMRT) after lumpectomy. Image from the publication

First, the authors assessed the use of IMRT and cRT. Among the entire cohort, 19.8% received IMRT, but the proportion varied by whether it was right sided (15.9%) or left sided (23.6%) breast cancer. This difference may reflect the fact that IMRT can expose the heart to lower doses of radiation compared to cRT, although the clinical outcomes associated with this have not been definitively demonstrated in clinical research. Assessment of IMRT use by individual SEER registry sites also revealed substantial differences. For example, use was very low in some regions, including 0% in Hawaii and 3.2% in Iowa, but much higher in other regions, such as 52.1% use in Detroit (see Figure). The factors most strongly associated with IMRT use included whether the Medicare local coverage decision status was ‘neutral’ or ‘favorable’ or if the patient was treated at a free-standing facility, suggesting that the possibility of Medicare reimbursement may play a role in IMRT use. Living in a big metropolitan area or in a census tract in which the median income was £ $90,000 were also significantly associated with IMRT treatment.

To determine whether receiving IMRT was associated with differences in medical expenditures, the authors calculated total expenses due to treatments, hospitalizations, physician visits, imaging and laboratory testing. In these calculations, the costs included those covered by Medicare as well as out-of-pocket fees not covered. The expenditures were calculated for the year following breast cancer diagnosis. Medical expenditures were significantly greater for women who received IMRT when compared with those who received cRT, with a mean difference of $8,499. The authors estimate that the increased costs associated with IMRT may account for more than $100 million in additional Medicare expenditures per year.

This study reveals considerable heterogeneity across the United States in the use of IMRT for treatment of early stage breast cancer patients prior to the IMRT-specific CW recommendation. With the high use of IMRT in some regions, these results support the recommendation and the goal to reduce the use of this type of radiation therapy in the absence of strong data demonstrating beneficial health impacts. Future studies may assess whether changes in IMRT use occurred after the 2013 CW recommendation.

This work was supported by the National Cancer Institute.

Fred Hutch/UW Cancer Consortium members Drs. Lia Halasz, Shilpen Patel, Bernardo Goulart, and Joshua Roth contributed to this research.

Halasz LM, Patel SA, McDougall JA, Fedorenko C, Sun Q, Goulart BHL, Roth JA. 2019. Intensity modulated radiation therapy following lumpectomy in early-stage breast cancer: Patterns of use and cost consequences among Medicare beneficiaries. PLoS ONE. doi: 10.1371/journal.pone.0222904.

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