Women age 65 and older diagnosed with early-stage hormone-receptor-positive breast cancer with a low risk of the cancer coming back had the same 10-year overall survival after lumpectomy and hormonal therapy whether or not they had radiation therapy, according to a study. The women who skipped radiation did have higher rates of local recurrence.
Overall survival is how long the women lived, whether or not the breast cancer came back (recurred). Local recurrence means the breast cancer came back in the breast area.
The research was presented on Dec. 9, 2020, at the 2020 San Antonio Breast Cancer Symposium. Read the abstract of “Prime 2 randomised trial (postoperative radiotherapy in minimum-risk elderly): Wide local excision and adjuvant hormonal therapy +/- whole breast irradiation in women =/> 65 years with early invasive breast cancer: 10 year results.”
About the study
“Over half the patients diagnosed with breast cancer in developed countries are over the age of 65 years,” said lead author Ian Kunkler, professor of clinical oncology at the Western General Hospital, University of Edinburgh, at a media briefing about the study. “Despite the less aggressive breast cancers typically diagnosed in this population, most patients who undergo [lumpectomy] continue to be treated with whole breast radiation therapy after surgery. We were interested in determining whether older patients with low-risk breast cancer could be spared radiation therapy.”
The study included 1,326 women age 65 and older diagnosed with early-stage hormone-receptor-positive breast cancer with no cancer in the lymph nodes (node-negative cancer). All the cancers were 3 cm or smaller in size, and all were considered to have a low risk of recurrence. All the women had lumpectomy to remove the breast cancer, and all the women were taking hormonal therapy medicine after surgery.
The women were randomly assigned to either receive whole breast radiation after lumpectomy or not:
- 668 women were not treated with radiation
- 658 women were treated with radiation
The researchers then monitored the women to see if the women treated with radiation therapy had better outcomes than women who weren’t treated with radiation therapy.
Half the women were followed for more than 7 years, and half were followed for shorter periods of time.
Ten years after the study started, rates of the cancer coming back in the same breast were:
- 9.8% for women not treated with radiation
- 0.9% for women treated with radiation
This difference was statistically significant, which means that it was likely due to the difference in treatment and not just because of chance.
When the researchers looked at distant/metastatic recurrence — the cancer coming back in a part of the body away from the breast, such as the bones or liver — rates were:
- 1.4% for women not treated with radiation
- 3.6% for women treated with radiation
Finally, 10-year overall survival rates were:
- 80.4% for women not treated with radiation
- 81.0% for women treated with radiation
Most of the deaths in each group — 91% in the women not treated with radiation and 96% of the women treated with radiation — were not because of breast cancer.
“We found that omitting postoperative radiation therapy did not compromise survival or increase the risk of distant metastasis,” Kunkler said. “Based on these results, we believe that omission of radiation therapy after breast-conserving surgery should be an option for older patients with localized, [hormone-receptor]-positive breast cancer who are receiving adjuvant hormone therapy and meet certain clinico-pathological criteria.”
What this means for you
If you’re age 65 or older and have been diagnosed with early-stage hormone-receptor-positive breast cancer with a low risk of recurrence and are deciding on your treatment plan, you may want to talk to your doctor about this study.
If you’re having lumpectomy and will be taking hormonal therapy after surgery, it may be possible for you to skip radiation therapy.
As you are making your treatment plan, you and your doctor will consider a number of factors, including:
- your age
- the size of the cancer
- the grade of the cancer
- any other health conditions you have
- your family history of cancer
- your personal preferences
Together, you can make the best treatment decisions for your unique situation.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, M.D., medical adviser
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