In a phase II trial reported in The Lancet Oncology, Henry Kuerer, MD, PhD, FACS, and colleagues found radiotherapy alone among women with triple-negative or HER2-positive invasive breast cancer who had pathologic complete response on percutaneous image-guided, vacuum-assisted core biopsy (VACB) after neoadjuvant systemic therapy may be a feasible treatment strategy, with promising early results reported.
Henry Kuerer, MD, PhD, FACS
In the U.S. multicenter trial, 50 patients with unicentric cT1–2N0–1M0 triple-negative (n = 21) or HER2-positive breast cancer (n = 29) and a residual breast lesion < 2 cm on imaging after clinically standard neoadjuvant systemic therapy, as selected by their medical oncologist, were enrolled between March 2017 and November 2021. Patients had one biopsy (minimum of 12 cores) obtained by 9G image-guided VACB of the tumor bed. If no invasive or in situ disease was identified, surgery was omitted and patients received standard whole-breast radiotherapy at 40 Gy in 15 fractions or 50 Gy in 25 fractions, plus a boost at 14 Gy in 7 fractions.
The primary outcome measure was biopsy-confirmed ipsilateral breast tumor recurrence rate in the per-protocol population.
Pathologic complete response on VACB was found in 31 (62%, 95% confidence interval [CI] = 47.2%–75.4%) of 50 patients, including 15 (71%) with triple-negative disease and 16 (55%) with HER2-positive disease (P = .24). Among patients with HER2-positive disease, pathologic complete response was found in 7 (39%) of 18 with hormone receptor–positive disease and 9 (81%) of 11 with hormone receptor–negative disease (P = .052).
At a median follow-up of 26.4 months (interquartile range = 15.2–39.6 months), no ipsilateral breast tumor recurrences were observed in the 31 patients with pathologic complete response on VACB. No other recurrence events and no deaths were observed, yielding recurrence-free survival and overall survival rates of 100%.
Complications of biopsy included grade 1 events in two patients (4%), consisting of nausea during the procedure that resolved without intervention in one and VACB device malfunction in the other; the malfunction was rectified and the procedure completed successfully. No serious adverse events or treatment-related deaths occurred.
The investigators concluded, “Eliminating breast surgery in highly selected patients with an image-guided VACB-determined pathological complete response following neoadjuvant systemic therapy is feasible with promising early results; however, additional prospective clinical trials evaluating this approach are needed.”
Dr. Kuerer, of the Department of Breast Surgical Oncology, The University of Texas MD Anderson Cancer Center, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by the National Cancer Institute. For full disclosures of the study authors, visit thelancet.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.