Phase II data report a pathologic complete response in patients who received radiotherapy after neoadjuvant therapy without surgery, when selected by image-guided vacuum-assisted core biopsy
Highly selected patients with breast cancer who underwent radiotherapy, but not surgery, reported a 0% ipsilateral breast tumour recurrence according to the results of a pre-planned, 3-year primary endpoint of a multicentre, prospective phase II trial presented at the ESMO Congress 2023 (Madrid, 20–24 October) (Abstract 243MO).
Following the promising outcomes of a feasibility study (J Am Coll Surg. 2023;237:101–108; Lancet Oncol. 2022;23:1517–1524), researchers investigated the benefits of omitting surgery after neoadjuvant systemic therapy (NST). The trial involved women with unicentric cT1-2N0-1M0 triple negative breast cancer (TNBC) or HER2-positive breast cancer and a residual breast lesion <2 cm on imaging after NST. In patients without invasive/in situ disease on a minimum 12-core 9G image-guided vacuum-assisted core biopsy (VACB) from the tumour bed, breast surgery was omitted and patients instead underwent whole-breast radiotherapy/boost.
Among 31 patients with VACB-determined pathologic complete response after NST, no recurrence was reported at a median follow-up of 38.4 months (interquartile range 27.6–51.8) and 3-year rates of disease-free and overall survival were 100%. Two patients were positive for circulating tumour cells (CTCs) at baseline, two were positive at 6 months, and one was positive at 12 months. No patients had CTCs detected at more than one timepoint.
The 50 patients enrolled in the study had a mean age of 60.4 years; 21 had TNBC and 29 had HER2-positive disease. The mean post-NST imaging tumour size was 0.90 cm (standard deviation 0.81) and 17 patients (34%) had a complete radiologic response.
The positive findings provide supporting evidence that image-guided VACB can be used to effectively select distinct patients who can safely receive radiotherapy without surgery. However, additional follow-up and further confirmation from clinical trials are needed before this approach becomes standard in clinical practice.
Kuerer HM, et al. Omission of breast surgery after neoadjuvant systemic therapy for invasive cancer: three-year preplanned primary-endpoint on a phase 2 multicentre prospective trial. ESMO Congress 2023, Abstract 243MO
Mini Oral Session – Breast cancer, early stage, 23.10.2023, h. 10.15 – 11.45, Bilbao Auditorium, NCC