Abemaciclib Plus Fulvestrant in Advanced Breast Cancer After Progression on CDK4/6 Inhibition: Results From the Phase III postMONARCH Trial
Yet another combination to consider after CDK4/6i + ET in HR+ MBC!
Omitting Radiotherapy after Breast-Conserving Surgery in Luminal A Breast Cancer
Author(s): Timothy J. Whelan, B.M., B.Ch., Sally Smith, M.D., Sameer Parpia, Ph.D., Anthony W. Fyles, M.D., Anita Bane, M.B., Fei-Fei Liu, M.D., Eileen Rakovitch, M.D., Lynn Chang, M.D., Christiaan Stevens, M.D., Julie Bowen, M.D., Sawyna Provencher, M.D., Valerie Théberge, M.D., Anna Marie Mulligan, M.D., Zuzana Kos, M.D., Ph.D., Mohamed A. Akra, M.D., K. David Voduc, M.D., Tarek Hijal, M.D., Ian S. Dayes, M.D., Gregory Pond, Ph.D., James R. Wright, M.D., Torsten O. Nielsen, M.D., Ph.D., and Mark N. Levine, M.D. for the LUMINA Study Investigators*
Source: N Engl J Med 2023; 389:612-619 DOI: 10.1056/NEJMoa2302344
Dr. Maen Hussein's Thoughts
For radiation oncologists: omitting radiation in patients with favorable features of 55 years of age and older.
Additional thoughts from FCS Radiation Oncologist Luis Carrascosa, MD:
This was not a phase 3 randomized trial and there is a lot of controversy regarding newer techniques such as 5-day partial breast irradiation (which I offer at FCS) which is a very good option for women in that age group rather than completely eliminating XRT. Additionally, the real question being investigated, and not addressed in this trial, is noncompliance with aromatase inhibitors and the significant side effects and costs associated with 5 years of endocrine therapy. I would love to have the opportunity to weigh in when we have papers like this.
My take would be: Multidisciplinary approach for breast cancer is recommended. In luminal A breast cancer in women over 55, there is a local control benefit with adjuvant XRT, however it is low. Discussion of shorter radiation schedules such as 5 fraction APBI for women over 55 with luminal A breast cancer is advisable in that subgroup. Encourage patient enrollment/participation in trials of APBI 5 fraction alone vs. 5 years of endocrine therapy alone.
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. opens in new tab.)
Author Affiliations
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.Related Articles
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