Impact of Level I Evidence on Radiation Therapy Utilization in Breast Cancer

Conventional radiation therapy (RT) regimens in breast conservation therapy (BCT) involve whole breast RT (WBRT), 45-50 Gy in 1.8-2.0 Gy fractions. The UK START and OCOG Trials showed the efficacy of hypofractionated (HF) regimens (39-42.5 Gy in 2.5-3.0 Gy fractions) in early stage breast cancer. CALGB established omission of RT as an option in select early stage breast cancer patients over 70. WBRT is most commonly delivered via 3D conformal RT (3DCRT) or intensity-modulated RT (IMRT). IMRT is estimated to be at least twice the cost of 3DCRT. In 2013, the American Society for Radiation Oncology released 5 practice recommendations as part of the national “Choosing Wisely” campaign. For breast cancer, clinicians are encouraged to (1) consider shorter treatment schedules for women ≥ 50 with early stage breast cancer and (2) not routinely use IMRT to deliver WBRT. To assess our uptake of new evidence and adherence to recommendations, we evaluated RT use in select breast cancer patients at our institution in two periods, 2006-2008, and 2011-2013. Inclusion criteria were completion of BCT at our institution, post-menopausal, invasive ductal carcinoma, T1-T2, N0, M0, ER/PR+, and HER2 normal. Two periods were assessed, 2006-2008 and 2011-2013, defined by date of surgery. Patients were identified from a prospective breast cancer database. Medical records were reviewed to define RT modality, dose, and fractionation schedule. Cases were analyzed on intent to treat basis. From 2006-2008, 66 cases met inclusion criteria (mean age 71.2, SD 9.0, range 51-89). RT utilization was as follows: HF WBRT in 12%, conventional WBRT in 52%, and brachytherapy (BT) in 20% of cases. RT was omitted in 17% of cases (mean age 80.6, SD 6.3, range 67-89) and 26% of patients over 70. From 2011-2013, 88 cases met inclusion criteria (mean age 70.7, SD 8.9, range 51-97). RT utilization was as follows: HF WBRT in 52%, conventional WBRT in 18%, and BT in 3% of cases. Of the 16 traditional schedule WBRT cases, 5 had perceived contraindications to HF WBRT, and 6 patients chose traditional over HF schedules. RT was omitted in 26% of cases (mean age 78.5, SD 7.4, range 61-97) and 44% of patients over 70. All WBRT was 3DCRT. No cases used IMRT. Among select early stage breast cancer patients pursuing WBRT at our institution, HF rate increased from 19% in 2006-2008 to 74% in 2011-2013 with no IMRT. National HF rates in this population were 11% in 2008 and 35% in 2013 with 9% IMRT. RT omission in patients over 70 at our institution increased roughly two-fold between the two periods. Our data shows rapid uptake of new evidence, adherence to national recommendations, and cost-effective practices at our institution. If national HF rates matched our institutional rates, the healthcare system could save as much as $22.7 million each year.