Women Treated for Breast Cancer May Age Faster Than Cancer-Free Women

Radiation ages breast cancer patients faster than other treatment methods, according to a new study.

New research out of the National Institutes of Environmental Health Sciences (NIEHS) found that individuals who underwent breast cancer treatment physically aged more than individuals who were not diagnosed with breast cancer.

The researchers also broke down which treatment method affected patients the greatest in regard to biological aging.

To do this, researchers used three different “methylation clocks” to determine if there were changes in a woman's biological age between two points in time—in the case of the study, two different blood draws. These clocks are designed to capture methylation patterns that are associated with biological age, age-related biological changes, chronic diseases, and mortality.

"There’s evidence that people with a methylation-based biological age that is older than their chronological age are at increased risk of developing disease and early death,” Dale Sandler, Ph.D., Chief of the Epidemiology Branch at NIEHS, an author of the paper, and the lead researcher for the Sister Study told Health.

“Increasingly sophisticated methylation-based measures of biological age are continuing to be published," Sandler said, "and our study uses three promising new measures, all of which can be measured in the DNA obtained from a blood sample.”

For breast cancer patients, radiation was seen to age patients the fastest, while surgery showed no association with biological aging.

Measuring Aging Amidst Breast Cancer

Participants in the new study were selected from the much larger Sister Study cohort of 50,884 women living in the United States, including Puerto Rico, enrolled between July 2003 and March 2009. Although men can develop breast cancer, they were not included in the study.

At enrollment, all participants had a sister, full or half, diagnosed with primary breast cancer, but had not been diagnosed with the disease themselves. Women in the study provided a blood sample and completed extensive questionnaires at the time of enrollment. Roughly eight to 10 years later a second blood sample was collected from a subset of those enrolled in the study.

Sandler explained that about half the women had developed breast cancer between enrollment and the second blood draw,

“This design allowed us to take into account a woman’s biological age at baseline when studying the association between breast cancer and biological age at the second time period," she said.

The study concluded that women who were diagnosed with breast cancer had faster biological aging rates, with no significant racial differences, compared to women who did not develop breast cancer.

Out of the treatment methods researched—surgery, chemotherapy, endocrine therapy, and radiation—radiation was shown to age patients the fastest.

How Radiation Impacts the Body

According to Lori Alfonse, DO, Deputy Physician in Chief of Lehigh Valley Topper Cancer Institute, radiation treatments are delivered in daily doses, ranging from 21 to 35 treatments, and reduce the risk of local recurrence of breast cancer from approximately 30%, with lumpectomy alone, to approximately 8%, with lumpectomy and radiation,

Cancer cells grow and divide faster than most healthy cells. Radiation works by making small breaks in the DNA inside the cells, which stop cancer cells from growing. Normal cells can be affected by radiation, but most recover.

Alfonse explained that radiation reduces the risk of recurrent disease when lumpectomy is the chosen surgical path. A lumpectomy is a surgery that conserves as much of the breast as possible while removing the cancer.

Radiation is rarely recommended for patients who are treated with a mastectomy—the removal of all at-risk breast tissue—Alfonse added.

One study found that exposure to these ultraviolet radiation or ionizing radiation can induce cellular DNA damage, which can cause cell senescence which can contribute to aging.

Alfonse pointed out that while radiation may impact a patient's biological age to a greater degree, it is not the only treatment method with noteworthy side effects.

“Radiation is a local treatment that causes fibrosis which may change the overall cell health of the breast tissue,” she said. “Surgery is also a local treatment that promotes scar tissue formation in the breast, and chemotherapy is a ‘global’ treatment that has systemic, total body side effects."

Continuing to Better Understand Radiation While Using It to Help Patients

While the new study concluded that radiation has a greater impact on aging than chemotherapy and surgery, researchers still don’t understand why.

“We were surprised that we did not see more evidence of change from chemotherapy,' Sandler said. "While current protocols try to minimize radiation exposures beyond the site of the breast tumors, we did not have information on how radiation was given or how many treatments women received.”

While all side effects are something to be considered before starting a treatment plan, the research team cautioned against using the study results as a reason to shift away from radiation therapy.

“Radiation is a valuable treatment option for breast cancer, and we don’t yet know why it was most strongly associated with biological age,” said Sandler.

She emphasized the importance of using the tools available to patients, as well as continued research to best understand how these tools impact women undergoing treatment.

“There is a large and growing population of breast cancer survivors in the US, which is a testament to early detection and improved treatments," she said. "These women are at increased risk of age-related diseases, and we hope that better understanding biological aging can help to minimize or eliminate these risks.”

For women who might be worried about the outcome of radiation for breast cancer treatment, a discussion with your treatment team regarding the risks and benefits of radiation is absolutely necessary, said Alfonse.

She noted that in some cases, radiation may be avoided in cases with advanced age, patients with favorable tumor biology, or a small tumor. 

“Radiation remains a valuable tool in the breast cancer treatment forum," Alfonse said. "And some food for thought is, perhaps the mere diagnosis of breast cancer and the anxiety and worry it causes patients has an effect on cell age by exposing them to increased levels of cortisol."