Cut to the chase.

Top Line: Is surgery necessary for breast cancer patients who have a complete response to neoadjuvant therapy?

The Study: Patients with HER2+ and TNBC who receive neoadjuvant therapy can have complete response rates exceeding 50%. In this single arm, phase 2 trial, 50 patients with cT1-2N0-1 (18% LN+) HER2+ (58%) or TNBC (42%) were enrolled after receiving standard neoadjuvant systemic therapy. Importantly, to be eligible, their residual breast lesion had to be <2 on mammogram or ultrasound. They underwent a vacuum-assisted core biopsy (VACB) under image guidance where a minimum of 12 cores were taken using a 9 gauge needle. The pathologic complete response rate was 62% (71% for TNBC, 55% for HER2+). Patients who had a pCR skipped surgery and went straight to whole breast radiation (50Gy/25 or 40Gy/15 plus a 14Gy/7 boost) while those without a pCR had surgery and then radiation. Of note, patients with initial nodal disease had to have a targeted axillary dissection to prove no residual nodal disease. With >2 years median follow up, there were no ipsilateral breast tumor recurrences among patients who had a pCR and omitted surgery. Is this approach ready for prime time? Of course not. While the systemic therapy and radiation were very standard, the breast imaging and biopsy techniques were highly specialized and may not be widely available at this time.

TBL: In this small trial of a highly select group of patients with a pCR to neoadjuvant systemic therapy, adjuvant radiation alone and omission of surgery results in a low risk of short-term recurrence. | Kuerer, Lancet Oncol 2022