It is safe to skip radiation in older women with early, low-risk disease. estrogen Receptor (ER)-positive breast tumors, researchers say Large Phase 3 trial Known as PRIME II.
“Our study will demonstrate the safety of radiotherapy in women 65 years and older with grade 1 or 2 ER-high cancer treated with breast-conserving therapy, provided they receive 5 years of adjuvant endocrine therapy. provide strong evidence that it can be omitted,” concluded the investigators led by the. Ian Kankler, MBProfessor of Clinical Oncology, University of Edinburgh, Scotland.
The trial randomly assigned 1,326 women. tumorectomy Either the whole breast or no background radiation Tamoxifen.
The incidence of local recurrence was lower with radiotherapy (0.9% vs. 9.5%), but there was no significant difference in distant or distant metastases. breast cancer– Specific or overall survival.
The findings “help clinicians guide older patients as to whether this particular aspect of early-stage breast cancer treatment can be omitted,” Kunkler said. press releaseRadiation carries the risk of damage to the heart and lungs, and these results show that skipping radiation does not increase mortality from breast cancer.
new research published February 15th New England Journal of Medicine.
A breast cancer radiation oncologist commented that “the doubt that radiation cannot be omitted in women who meet the criteria can be dispelled.” Alice Ho, M.D.Duke University, Durham, North Carolina, and Jennifer Veron, M.D.of Harvard University in Boston editorial.
Clinical guidelines already support omission radiotherapy In older women with low-risk tumors treated with lumpectomy and endocrine therapy, this move is controversial due to lack of long-term data, and the use of radiation for such women is controversial. It’s still common in the United States, researchers explain.
The trial’s “highly promising” 10-year outcome results not only help address that problem, but also “the long-standing problem of overtreatment in older women with low-risk breast cancer.” The editor commented that it should be useful for
Survey details
PRIME II was implemented mainly in the UK from 2003 to 2009. Participants were aged 65 years or older and had a T1 or T2 ER-positive tumor ≤3 cm in size with no lymph node involvement.
After a lumpectomy with clear margins, women received endocrine therapy. Researchers recommended taking tamoxifen at 20 mg/day for her five years.
Women randomly assigned to radiation also received 40-50 Gy whole-breast irradiation in 20-25 doses over 3-5 weeks.
At 10 years, 1.6% of women in the non-radiation group had distant metastases as their first recurrence compared to 3% of women who received radiation therapy.
Breast cancer-specific 10-year survival was 97.9% with radiotherapy and 97.4% without radiotherapy. The 10-year overall survival rate was 80.7% in the radiotherapy group compared to 80.8% in the no radiotherapy group.
Furthermore, the recurrence rate after irradiation was low. The researchers suggest that lower endocrine therapy adherence and lower levels of ER positivity are associated with a higher risk of local recurrence in women who have not undergone radiation therapy.
Nearly 10% of women who did not receive radiation had a local recurrence by 10 years, but the researchers found that women still had the option of a second lumpectomy, even if their tumors recurred locally. , points out that you can get radiation if you want. , so local recurrence “does not necessarily mean breast loss”.
PRIME II was funded by the Scottish Government’s Chief Scientist Office and the Breast Cancer Institute, Western General Hospital, Edinburgh. Kunkler reports no conflicts of interest. The co-authors have acted as speakers, advisors and/or researchers for many companies including Hoffmann-La Roche, Exact Sciences, Eli Lilly and others. Ho reported grants and/or consultants from GlaxoSmithKline, Roche, Merck and others. Bellon reported relationships with Varian Medical Systems and Veracyte.
N Eng J Med. Published February 15, 2023. overview, editorial
M. Alexander Otto is a Physician Assistant with a Master of Medicine and Journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news organizations before joining Medscape. Alex is also an MIT Knight Science Journalism Fellow. Email: [email protected].
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