Omission of Radiation in Conservative Treatment for Breast Cancer: Opportunity for De-escalation of Care.

INTRODUCTION: De-escalation of breast cancer treatment aims to reduce patient and financial toxicity without compromising outcomes. Level I evidence and National Comprehensive Cancer Network guidelines support omission of adjuvant radiation in patients aged >70 y with hormone-sensitive, pT1N0M0 invasive breast cancer treated with endocrine therapy. We evaluated radiation use in patients eligible for guideline concordant omission of radiation. METHODS: Subgroup analysis of patients eligible for radiation omission from two pooled randomized controlled trials, which included stage 0-III breast cancer patients undergoing breast conserving surgery, was performed to evaluate factors associated with radiation use. RESULTS: Of 631 patients, 47 (7.4%) met radiation omission criteria and were treated by 14 surgeons at eight institutions. The mean age was 75.3 (standard deviation + 4.4) y. Majority of patients identified as White (n = 46; 97.9%) and non-Hispanic (n = 44; 93.6%). The mean tumor size was 1.0 cm; 37 patients (88.1%) had ductal, 4 patients (9.5%) had lobular, and 17 patients (40.5%) had low-grade disease. Among patients eligible for radiation omission, 34 (72.3%) patients received adjuvant radiation. Those who received radiation were significantly younger than those who did not (74 y, interquartile range = 4 y, versus 78 y, interquartile range = 11 y, P = 0.03). There was no difference in radiation use based on size (P = 0.4), histology (P = 0.5), grade (P = 0.7), race (P = 1), ethnicity (P = 0.6), institution (P = 0.1), gender of the surgeon (P = 0.7), or surgeon (P = 0.1). CONCLUSIONS: Fewer than 10% of patients undergoing breast conservation met criteria for radiation omission. Nearly three-quarters received radiation therapy with younger age being a driver of radiation use, suggesting ample opportunity for de-escalation, particularly among younger eligible patients.

Initial Results of Multigene Panel Testing for Hereditary Breast and Ovarian Cancer and Lynch Syndrome.

Multigene panel testing for hereditary cancer risk has recently become commercially available; however, the impact of its use on patient care is undefined. We sought to evaluate results from implementation of panel testing in a multidisciplinary cancer center. We performed a retrospective review of consecutive patients undergoing genetic testing after initiating use of multigene panel testing at Loma Linda University Medical Center. From February 13 to August 25, 2014, 92 patients were referred for genetic testing based on National Comprehensive Cancer Network guidelines. Testing was completed in 90 patients. Overall, nine (10%) pathogenic mutations were identified: five BRCA1/2, and four in non-BRCA loci. Single-site testing identified one BRCA1 and one BRCA2 mutation. The remaining mutations were identified by use of panel testing for hereditary breast and ovarian cancer. There were 40 variants of uncertain significance identified in 34 patients. The use of panel testing more than doubled the identification rate of clinically significant pathogenic mutations that would have been missed with BRCA testing alone. The large number of variants of uncertain significance identified will require long-term follow-up for potential reclassification. Multigene panel testing provides additional information that may improve patient outcomes.