DISCUSSION

Among patients with early-stage breast cancer who had WBRT at our NCCN member institution, the hypofractionation rate increased from 14% in 2006–2008 to 74% in 2011–2013 (Figure 1). These hypofractionation rates compare favorably to national rate trends, including the subset of academic institutions. An analysis based on the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database showed hypofractionation rates of 10% in 2008 and 14% in 2009–2010 for early-stage breast cancer.21 Retrospective data from the National Cancer Database demonstrated that for patients deemed eligible for hypofractionation, national hypofractionation rates increased from 10% in 2008 to 23% in 2011, with increasing rates of hypofractionation in academic institutions from ~16% in 2008 to ~32% in 2011.22 More recently, a report from the Michigan Radiation Oncology Quality Consortium showed that 31% of patients with early-stage breast cancer registered from October 2011 to December 2013 received hypofractionated WBRT.23 A retrospective analysis using administrative claims data from commercial health care plans covering 7% of the adult female population in the USA showed that the rates of hypofractionated WBRT for women aged ≥50 years with early-stage breast cancer were 11% in 2008 and 35% in 2013.24 While these comparisons show a trend toward increased hypofractionation nationwide, our institution seems to have adopted the shorter treatment schedule to a far greater extent.

RT omission for patients aged >70 years with early-stage breast cancer increased by nearly 20% between the two periods we evaluated at our institution (29%–48%, Figure 1). According to a SEER database analysis, national rates of RT omission for this group were 31% between 2000 and 2004 and 38% between 2005 and 2009.25 As of 2011–2013, the rate of RT omission for women aged >70 years at our institution exceeds the published national rates. Based on CALGB 9343,12 current NCCN guidelines13 use age 70 years as a cutoff for the selected option of RT omission. However, multiple additional trials are now evaluating RT omission for younger patients who are still at low risk of recurrence. PRIME II has published 5-year data on RT omission for patients aged ≥65 years.26Ongoing studies include the IDEA Study27 (postmenopausal patients), the PRECISION Trial28 (patients aged ≥50 years), and the EXPERT Trial29 (patients aged ≥50 years). If long-term results from these trials are favorable, RT omission may become an option for even younger patients.


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Of the 16 patients who received the traditional schedule WBRT from 2011 to 2013, six patients preferred the longer schedule and five had a large breast separation, which has been a perceived contraindication to hypofractionated WBRT.6 Thus, only five of 88 patients were treated with the longer traditional radiation schedule without a clearly documented rationale for not using the shorter hypofractionated schedule. Although the OCOG trial excluded women with a maximum width of breast tissue of over 25 cm, the START trials had no breast separation limitations.6–8 Other studies have shown larger body habitus (proxy for large breast separation) to be associated with lack of hypofractionation.21,23 IMRT may be an appropriate modality to minimize adverse effects for patients with large breast separation who are undergoing hypofractionation, thus broadening the applicability of the hypofractionated schedule.30

Factors associated with higher hypofractionation rates include both patient and institutional characteristics, such as living ≥50 miles from the cancer reporting facility,22 treatment at an academic center,22 higher median income,22,24 older age,21,23,24 higher education level, living in a western SEER region, and more comorbidity.21 Bekelman et al24 also found hypofractionation more likely to occur in an outpatient hospital setting versus a freestanding facility. Our institution is a tertiary academic center in the western USA that spans both outpatient hospital and freestanding facilities. Although we did not investigate these patient demographic characteristics, it is possible that the patient population in our study is unbalanced with regard to the abovementioned variables, resulting in selection bias.

In contrast to the slower national uptake of hypofractionated WBRT and the selected option of RT omission, IMRT has shown rapid acceptance despite limited supportive evidence. Among patients with node-negative breast cancer, IMRT use in breast conservation increased from 9% in 2004 to 23% in 2009 to 2010.21 IMRT was not used at our institution for patients aged ≥50 years with hormone receptor-positive, early-stage breast cancer. Some providers argue that IMRT can deliver a more homogeneous radiation dose and thus reduce toxicity. However, our practice is to use field-in-field 3DCRT technique, which achieves dose homogeneity comparable to inverse-planned IMRT.31 Although hypofractionated regimens and RT omission reduce cost, IMRT is more costly than 3DCRT.14 At current reimbursement levels, IMRT is associated with an estimated added cost of $4,034.46 and $7,146.06 for 15- and 25-fraction WBRT courses, respectively (Table 2). Whether providers are making a conscious effort or not, it would stand to reason that financially advantageous practices, such as the use of IMRT, would be used more commonly than their cheaper counterparts. This type of financial incentive has been previously demonstrated for IMRT use among self-referring urologists32and may similarly impact national IMRT utilization, as well as lack of hypofractionation and RT omission in early-stage breast cancer.

Potential cost savings may be substantial if providers follow evidence-based practice guidelines and expert recommendations for selected patients with early-stage breast cancer. According to the ASTRO evidence-based guidelines, each year, about 20,000 women who have WBRT are eligible for hypofractionation. About 2,000 of these patients ultimately receive IMRT. About 4,000 are aged >70 years and eligible for RT omission.24 By our own assessment (Table 2), the direct medical cost of a single course of WBRT using 15 fractions 3DCRT is less than half the cost of 25 fractions IMRT, a savings of nearly $10,000 in direct medical costs per patient by selecting hypofractionated 3DCRT over traditional course IMRT. RT omission removes the cost of RT entirely, a savings of about $7,000–$17,000 per patient. Practice patterns with regard to WBRT for early-stage breast cancer affect thousands of patients per year, who could each save thousands of dollars in direct medical costs if hypofractionation or RT omission is chosen. Given these data, choosing hypofractionated WBRT when appropriate, omitting RT for selected elderly women, and avoiding unnecessary IMRT could ultimately account for millions of dollars in direct medical cost savings to the US healthcare system – all while adopting evidence-based practices.