Top Line: All those who have purchased intra-op radiation devices aren't going to let the Florence trial have all the glory.
The Study: The phase 3 TARGIT-A trial randomized nearly 2300 women planned for lumpectomy for grade 1-2 invasive ductal carcinoma <3.5 cm to standard adjuvant whole breast irradiation over 3-6 weeks with or without a boost per pre-specified institutional criteria versus a single intraoperative radiation treatment (IORT) at time of lumpectomy via the Intrabeam device. The kicker was, of course, that final pathology wasn’t available for review until after the IORT was delivered. If high risk features [margin <1 mm, extensive (>25%) in situ component, invasive lobular component, grade 3, node positivity, lymphovascular invasion] was present on surgical path, women in the IORT arm proceeded with standard adjuvant whole breast irradiation with the IORT serving as the boost. The primary endpoint was establishing non-inferior local control, predefined as a difference <2.5% at 5 years. At 5 years, these rates were 1.0% with standard whole breast irradiation versus 2.1% with IORT, meeting non-inferiority. All of this should also be taken in the context of better self-reported cosmesis at 5 years in the IORT arm. Importantly, 1 of every 5 women receiving IORT still required whole breast irradiation based on high-risk features discovered at surgery—though they’re not really losing out on much considering that was their only alternative for standard care, anyway.TBL: As long as you have the device, IORT remains another good option for women with favorable breast cancer notwithstanding roughly 1 in 5 still require subsequent whole breast treatment. | Vaidya, BMJ 2020