Can Some Older Women Skip Radiation After Lumpectomy for Low-Risk Breast Cancer?
Certain older women diagnosed with hormone receptor-positive, HER2-negative breast cancer that has a low recurrence risk (the cancer coming back) can take hormonal therapy alone and skip radiation therapy after lumpectomy, according to a study. Still, you and your doctor need to consider a number of factors when deciding on treatments after surgery.
The research was published on Aug. 17, 2023, by The New England Journal of Medicine. Read the abstract of “Omitting Radiotherapy after Breast-Conserving Surgery in Luminal A Breast Cancer.”
Luminal A breast cancer
Luminal A breast cancer is a molecular subtype of breast cancer that is estrogen receptor- and progesterone receptor-positive, HER2-negative, and has low levels of the Ki-67 protein — a protein that helps control how fast cancer cells grow. Luminal A cancers tend to grow more slowly than other breast cancers, have a lower grade, and have a good prognosis. Luminal A is the most common subtype of breast cancer; researchers estimate that it makes up at least half of all new breast cancer diagnoses.
About the study
Called LUMINA, this study included 500 women ages 55 and older diagnosed with early-stage luminal A ductal breast cancer who received treatment at 26 centers in Canada.
For this study, the researchers defined luminal A breast cancer as having:
estrogen receptors on 1% or more of the cancer cells
progesterone receptors on more than 20% of the cancer cells
no HER2 receptors, meaning the cancer was HER2-negative
Ki-67 protein levels of 13.25% or lower
The researchers excluded women diagnosed with lobular breast cancer from the study.
All the women had lumpectomy surgery to remove the cancer followed by at least five years of hormonal therapy — either an aromatase inhibitor or tamoxifen. The women enrolled in the study between August 2013 and July 2017.
People commonly receive radiation therapy after lumpectomy because it reduces the risk of recurrence. Research shows that lumpectomy plus radiation offers the same outcomes as mastectomy.
Still, radiation therapy may be inconvenient for some people because it usually involves daily trips to the treatment center for three to seven weeks. Radiation therapy also can cause side effects, including fatigue and skin blistering and peeling.
In this study, the researchers wanted to know if women diagnosed with small, early-stage luminal A breast cancer that had a very low risk of recurrence could safely skip radiation after lumpectomy if they took hormonal therapy.
But it’s important to know that hormonal therapy also can cause side effects, including hot flashes, joint pain, and fatigue. Research has shown that about 25% of women who are prescribed hormonal therapy to reduce the risk of recurrence either don’t start the medicine or stop taking it early because of troubling side effects.
The women had follow-up visits every six months for two years, and then every year after that. The researchers followed half the women for less than five years, and half for a longer period of time.
The researchers reported that 82.7% of the women were still taking hormonal therapy at their last follow-up visit.
It’s also important to know that estrogen receptor-positive breast cancer has a higher risk of recurring more than 10 years after diagnosis than hormone receptor-negative breast cancer.
After about five years of follow-up:
10 women were diagnosed with breast cancer in the same breast (local recurrence)
8 women were diagnosed with breast cancer in the opposite breast (contralateral breast cancer)
2 women were diagnosed with breast cancer in a part of the body away from the breast (distant recurrence)
13 women died, but only one woman died of breast cancer
So the overall recurrence rate at five years was 2.7%. What we don’t know is how many more recurrences might happen after 10 years of follow-up.
What this means for you
If you’re 55 or older and have been diagnosed with early-stage, hormone receptor-positive, HER2-negative breast cancer that has a very low risk of recurrence and are deciding on treatments after lumpectomy, this study offers interesting results that seem encouraging. But there are other things to keep in mind when developing your treatment plan, according to Marisa Weiss, MD, Breastcancer.org founder and chief medical officer.
“This is the most favorable subtype of breast cancer, so it’s no surprise that it was associated with a low risk of recurrence with endocrine therapy alone at five years of analysis,” Dr. Weiss explained. “But five years is relatively short follow-up in this subgroup because we know that hormone receptor-positive breast cancer has an elevated risk of recurrence well after five years. We also know that a significant number of people who choose to take hormonal therapy instead of receiving radiation end up discontinuing the medicine due to side effects, so they don’t receive the full benefit of the medicine.”
Dr. Weiss also pointed out that there are shorter radiation schedules now. Accelerated or hypofractionated radiation therapy puts a traditional five- to seven-week schedule into a three- to five-week schedule.
Listen to The Breastcancer.org Podcast episode featuring Dr. Chirag Shah explaining the benefits and drawbacks of a hypofractionated radiation schedule.
Brachytherapy, or internal radiation, uses small pieces of radioactive material, called seeds, which are placed in the area around where the cancer was. Brachytherapy treatment usually takes five days and you receive two treatments each day.
“Short-course breast radiation makes this option more accessible and reasonable — and just as effective — for more people,” Dr. Weiss said.
“Most women age 55 and older who are in good health are likely to live much longer than five years after being diagnosed with early-stage breast cancer,” she added. “These individuals have the right to exercise their autonomy and are entitled to shared decision-making with their doctors to determine what is best for them and their unique situations. A careful conversation with their doctors about their risk assessment should include other factors, such as modern genomic and inherited genetic testing, and their willingness to take various steps to lower their risk, such as sticking to their hormonal therapy treatment plan.”
— Last updated on October 5, 2023 at 3:29 PM