MIAMI BEACH – The use of radiation therapy should be decreased in women at low risk of local recurrence of breast cancer, Dr. Kevin S. Hughes said at the annual Miami Breast Cancer Conference.
This is particularly true for women aged 70 years and older with clinical stage 1, estrogen receptor–positive cancers, but may also apply to younger women with low recurrence risk, Dr. Hughes, codirector of the Avon Comprehensive Breast Cancer Evaluation Center at Massachusetts General Hospital, Boston, said at the conference, held by Physicians’ Education Resource.
Older women have lower-risk breast cancers that are more responsive to hormonal treatments, he explained, noting that Cancer and Leukemia Group B protocol 9343 showed that radiation therapy provides little benefit among older women; the 10-year recurrence of 9% in those treated with conservation and radiation therapy was similar to the recurrence rate among women under age 40 years, and to the unilateral cancer risk of a patient with lobular carcinoma in situ.
No difference was seen in ultimate breast preservation, distant disease-free survival, or survival in those with vs. without radiation therapy, he said.
In fact, 94% of patients who died at the time of 12-year follow-up died of something other than breast cancer, he noted.
Despite efforts over the years to publicize these and similar findings, the use of radiation therapy in this population has not declined substantially.
“It is important to stop using radiation in older women who don’t benefit from this therapy and don’t really need it,” he stressed.
As for younger women, the PRIME II trial showed similar results in 658 women aged 65 years and older, and the PRECISION (Profiling Early Breast Cancer for Radiotherapy Omission) trial will look at women aged 50-75 years with stage 1, ER+ cancer who are at low risk of recurrence, Dr. Hughes said.
In PRIME II, postoperative whole-breast radiotherapy after breast-conserving surgery and adjuvant endocrine treatment provided some reduction in the local recurrence at 5-year follow-up, but the investigators concluded that the rate of ipsilateral breast tumor recurrence “is probably low enough for omission of radiotherapy to be considered for some patients (Lancet. 2015;16[3]:266-73).
The findings in older women are clear with the respect to the need for avoiding radiation therapy in those with low local recurrence risk, and the findings in younger women are promising, he concluded.
Dr. Hughes is on the speakers bureau for Myriad Genetics, is a shareholder of the healthcare IT company 5AM Solutions, and is the founder (with a financial interest) of Hughes Risk Apps, LLC.