Key clinical point: De-escalation of locoregional radiotherapy, according to a predefined consensus-based study guideline, was oncologically safe in women with cT1-2N1 breast cancer (BC) who received primary chemotherapy.
Major finding: The 5-year locoregional recurrence rate was 2.2% (95% CI 1.4%-3.4%) in the overall cohort, with the rates being similar in the low- vs intermediate-risk group (P = .89), low- vs high-risk group (P = .75), and intermediate- vs high-risk group (P = .83) and the 5-year locoregional recurrence rate remaining < 4% as per the study guideline.
Study details: Findings are from a prospective registry study including 838 patients with cT1-2N1 invasive BC who were treated with ≥3 cycles of primary chemotherapy and surgery of the breast and axillary and were categorized into three predefined risk categorized based on axillary lymph node status.
Disclosures: This study was funded by the Dutch Cancer Society. Some authors declared holding patents, serving as the chair of a committee, or receiving grants, consulting fees, or financial and nonfinancial support from several sources.
Source: de Wild SR et al. De-escalation of radiotherapy after primary chemotherapy in cT1-2N1 breast cancer (RAPCHEM; BOOG 2010-03): 5-year follow-up results of a Dutch, prospective, registry study. Lancet Oncol. 2022;23(9):1201-1210 (Aug 8). Doi: 10.1016/S1470-2045(22)00482-X