保乳手术后 Luminal A 型乳腺癌中省略放疗。
Omitting Radiotherapy after Breast-Conserving Surgery in Luminal A Breast Cancer.
机构信息
From the Department of Oncology, McMaster University and the Division of Radiation Oncology, Juravinski Cancer Centre at Hamilton Health Sciences, Hamilton, ON (T.J.W., I.S.D., J.R.W.), the Division of Radiation Oncology, Department of Surgery, University of British Columbia and Radiation Therapy Program, BC Cancer Agency, Victoria (S.S.), the Department of Oncology, McMaster University, Hamilton, ON (S. Parpia, G.P., M.N.L.), the Department of Radiation Oncology, University of Toronto, and the Radiation Medicine Program, Princess Margaret Cancer Centre (A.W.F., F.-F.L.), the Department of Pathology, University of Toronto (A.B.), and the Department of Radiation Oncology, University of Toronto and Sunnybrook Odette Cancer Centre (E.R.), Toronto, the Department of Radiation Oncology, University of Ottawa and Ottawa Regional Cancer Centre, Ottawa (L.C.), the Department of Radiation Oncology, University of Toronto and Royal Victoria Regional Health Centre, Barrie, ON (C.S.), the Department of Radiation Oncology, Laurentian University and Radiation Treatment Program, Northeast Cancer Centre, Health Sciences North, Sudbury, ON (J.B.), the Department of Radiation Oncology, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC (S. Provencher), the Department of Radiation Oncology, Centre Hospitalier Universitaire de Québec-Université Laval, Quebec, QC (V.T.), the Department of Laboratory Medicine and Pathobiology, and the Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto (A.M.M.), the Department of Pathology and Laboratory Medicine, University of British Columbia, and the BC Cancer Agency, Vancouver (Z.K.), the Department of Radiation Oncology, University of Manitoba and Cancer Care Manitoba, Winnipeg (M.A.A.), the Department of Radiation Oncology, University of British Columbia and Radiation Therapy Program, BC Cancer Agency, Vancouver (K.D.V.), the Department of Radiation Oncology, McGill University, Montreal (T.H.), and the Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver (T.O.N.) - all in Canada.
出版信息
N Engl J Med. 2023 Aug 17;389(7):612-619. doi: 10.1056/NEJMoa2302344.
BACKGROUND
Adjuvant radiotherapy is prescribed after breast-conserving surgery to reduce the risk of local recurrence. However, radiotherapy is inconvenient, costly, and associated with both short-term and long-term side effects. Clinicopathologic factors alone are of limited use in the identification of women at low risk for local recurrence in whom radiotherapy can be omitted. Molecularly defined intrinsic subtypes of breast cancer can provide additional prognostic information.
METHODS
We performed a prospective cohort study involving women who were at least 55 years of age, had undergone breast-conserving surgery for T1N0 (tumor size <2 cm and node negative), grade 1 or 2, luminal A-subtype breast cancer (defined as estrogen receptor positivity of ≥1%, progesterone receptor positivity of >20%, negative human epidermal growth factor receptor 2, and Ki67 index of ≤13.25%), and had received adjuvant endocrine therapy. Patients who met the clinical eligibility criteria were registered, and Ki67 immunohistochemical analysis was performed centrally. Patients with a Ki67 index of 13.25% or less were enrolled and did not receive radiotherapy. The primary outcome was local recurrence in the ipsilateral breast. In consultation with radiation oncologists and patients with breast cancer, we determined that if the upper boundary of the two-sided 90% confidence interval for the cumulative incidence at 5 years was less than 5%, this would represent an acceptable risk of local recurrence at 5 years.
RESULTS
Of 740 registered patients, 500 eligible patients were enrolled. At 5 years after enrollment, recurrence was reported in 2.3% of the patients (90% confidence interval [CI], 1.3 to 3.8; 95% CI, 1.2 to 4.1), a result that met the prespecified boundary. Breast cancer occurred in the contralateral breast in 1.9% of the patients (90% CI, 1.1 to 3.2), and recurrence of any type was observed in 2.7% (90% CI, 1.6 to 4.1).
CONCLUSIONS
Among women who were at least 55 years of age and had T1N0, grade 1 or 2, luminal A breast cancer that were treated with breast-conserving surgery and endocrine therapy alone, the incidence of local recurrence at 5 years was low with the omission of radiotherapy. (Funded by the Canadian Cancer Society and the Canadian Breast Cancer Foundation; LUMINA ClinicalTrials.gov number, NCT01791829.).
背景
保乳手术后会进行辅助放疗，以降低局部复发的风险。然而，放疗既不方便，又昂贵，还会带来短期和长期的副作用。仅依靠临床病理因素，对于那些可以省略放疗且局部复发风险较低的女性，识别能力有限。乳腺癌的分子定义固有亚型可以提供额外的预后信息。
方法
我们进行了一项前瞻性队列研究，纳入年龄至少 55 岁、接受保乳手术治疗 T1N0（肿瘤大小<2cm 且无淋巴结转移）、G1 或 G2、管腔 A 型乳腺癌（定义为雌激素受体阳性率≥1%、孕激素受体阳性率>20%、人表皮生长因子受体 2 阴性、Ki67 指数≤13.25%）、并接受辅助内分泌治疗的女性。符合临床入选标准的患者进行登记，并进行 Ki67 免疫组化分析。Ki67 指数为 13.25%或更低的患者被纳入研究，并且不接受放疗。主要结局是同侧乳房的局部复发。根据放射肿瘤学家和乳腺癌患者的建议，如果 5 年累积发生率双侧 90%置信区间上限<5%，则代表可接受的 5 年局部复发风险。
结果
在 740 名登记的患者中，有 500 名符合条件的患者入选。在入组后 5 年时，有 2.3%的患者报告复发（90%置信区间 [CI]，1.3 至 3.8；95%CI，1.2 至 4.1），该结果符合预设边界。有 1.9%的患者对侧乳房发生乳腺癌（90%CI，1.1 至 3.2），2.7%的患者发生任何类型的复发（90%CI，1.6 至 4.1）。
结论
在接受保乳手术和内分泌治疗的年龄至少 55 岁、T1N0、G1 或 G2、管腔 A 型乳腺癌的女性中，省略放疗 5 年时局部复发率较低。（由加拿大癌症协会和加拿大乳腺癌基金会资助；LUMINA ClinicalTrials.gov 编号：NCT01791829。）
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