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Locoregional Recurrence With Predefined Risk-Based De-escalation of Radiotherapy After Primary Chemotherapy in cT1–2N1 Breast Cancer


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As reported in The Lancet Oncology by de Wild et al, 5-year follow-up from a Dutch prospective registry study (RAPCHEM, BOOG 2010-03) showed low rates of locoregional recurrence with de-escalation of adjuvant radiotherapy according to predefined risk levels in women receiving primary chemotherapy and surgery for cT1-2N1 breast cancer.

Study Details

The 5-year analysis included 838 eligible women, enrolled between January 2011 and January 2015, with cT1-2N1 breast cancer (1–3 suspicious nodes on imaging before primary chemotherapy, of which at ≥ 1 had been pathologically confirmed) who were treated with primary chemotherapy and surgery. Patients were assigned to predefined risk groups for locoregional recurrence: low = ypN0; intermediate = ypN1, one to three positive nodes in the surgical specimen after primary chemotherapy; or high = ypN2-3, four or more positive nodes in the surgical specimen after primary chemotherapy.

Patients in the low-risk group (n = 291) received no chest wall radiotherapy and no regional radiotherapy; those in the intermediate-risk group (n = 370) received only local radiotherapy; and those in the high-risk group (n = 177) received locoregional radiotherapy. Radiotherapy consisted of a biologically equivalent dose of 25 fractions of 2 Gy with or without a boost. It was hypothesized that the 5-year locoregional recurrence rate would be < 4% (upper limit of 95% confidence interval [CI] = 7.8%).

Key Findings

Among all patients, 5-year locoregional recurrence was 2.2% (95% CI = 1.4%–3.4%). According to assigned risk group, rates were 2.1% (95% CI = 0.9%–4.3%) in the low-risk group, 2.2% (95% CI = 1.0%–4.1%) in the intermediate-risk group, and 2.3% (95% CI = 0.8%–5.5%) in the high-risk group.

Totals of patients in the risk groups who received radiotherapy according to the study guideline were 181 (62%) in the low-risk group (37% received more radiotherapy; 1%, less), 200 (54%) in the intermediate-risk group (29% received more; 17%, less), and 152 (86%) in the high-risk group (14% received less). Among patients receiving guideline radiotherapy, 5-year locoregional recurrence was 2.3% (95% CI = 0.8%–5.3%) in the low-risk group, 1.0% (95% CI = 0.2%–3.4%) in the intermediate-risk group, and 1.4% (95% CI = 0.3%–4.5%) in the high-risk group.

The investigators concluded, “In this study, the 5-year locoregional recurrence rate was less than 4%, which supports our hypothesis that it is oncologically safe to de-escalate locoregional radiotherapy based on locoregional recurrence risk in selected patients with cT1–2N1 breast cancer treated with primary chemotherapy, according to this predefined, consensus-based study guideline.”

Sabine R. de Wild, MD, of the Department of Surgery, Maastricht University Medical Centre+, is the corresponding author for The Lancet Oncology article.  

Disclosure: The study was funded by the Dutch Cancer Society. 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®.
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