Breast Cancer-Specific Mortality Differs Among Men, Women Over Time

Periods of time for heightened risk of breast cancer differ between men and women with breast cancer.

The risk of breast cancer-specific mortality persists for at least 20 years in men with stages 1 to 3 hormone-receptor (HR)-positive breast cancer, according to a study published in JAMA Network.

Researchers from the study identified that the kinetics of breast cancer-specific mortality were different when compared with women, which may include age and tumor stage.

Kinetics for the risk of death from breast cancer is the “means of distribution of the risk that patients have,” Dr. Jose Pablo Leone explained to CURE®.

Leone is a co-author of the study, a medical oncologist and director of the program for breast cancer in men at Dana-Farber Cancer Institute. He is also an assistant professor of medicine at Harvard Medical School.

He and fellow researchers determined that two peaks of time lead to a higher risk of breast cancer mortality in men.

“There are two peaks — or two time points — where the risk is higher, and those occur at approximately four to five years [for] the first peak, and the second peak occurred somewhere around 11 or 12 years,” Leone said. “Those peaks were more notable in patients with higher stages of breast cancer, especially stage three.”

Risk Factors Contributing to Different Kinetics in Men With Breast Cancer

Regarding the differences in kinetics, Leone stated that certain risk factors could contribute to earlier peaks.

“The risk overall depended on general risk factors, such as the age at the time of diagnosis of breast cancer, the tumor stage and the tumor grade,” he explained. “For example, specifically for the stage of breast cancer, we saw that the peaks occurred earlier in time. They also have a higher magnitude in the peaks as the stage went up higher.”

READ MORE: What to Expect: Hormonal Side Effects from Breast Cancer Treatment

Differences Between Kinetics in Men and Women

Of note, the researchers also found that men with breast cancer who had higher stages of disease had different kinetics of breast cancer-related mortality compared with what has been determined for women.

Leone said that there were similarities and differences among men and women.

“We found in our study that, in general, the total risk of breast cancer-specific mortality over 20 years appeared similar between men and women,” he said. “What is different is the distribution of that risk — the index of that risk — is what appears to be different between men and women. In men in our study, we saw the bimodal distribution (two peaks), whereas in women, we [saw] a single peak in risk that occurs somewhere around years five and six.

“So there is an increase in a relatively linear manner. Whereas in men, there is a decrease after the first peak, but then there is a second increase — the second peak — which has not been recorded in women.”

Hypotheses Regarding Differences in Peaks Between Men and Women

Leone noted that although this discrepancy was not analyzed in the study, he mentioned a few hypotheses that may contribute to differences.

“[The first hypothesis is] differences in endocrine therapy between men and women. But we think that it’s overall unlikely that differences in endocrine therapy will lead to differences in the distribution of risk that we saw in the study,” Leone considered.

Reasons for the second peak in men may be from differences in tumor biology, Leone explained.

“There could be differences in cancer senescence, or how long the cancer cells stay up to check without growing again,” he said. “That could be different between male and female breast cancer.

“Another difference could be in the tumor microenvironment and the immunological differences between men and women, and whether that would in turn lead to a higher likelihood of cancer recurrence in men at a later time after diagnosis compared to women.”

Treatment Options for Men With Breast Cancer

Leone stated that a couple of treatment options are used for men with HR-positive breast cancer, including endocrine therapy and chemotherapy.

“Treatments that we have available for HR-positive breast cancer are endocrine therapy and chemotherapy, [which] are both options that we use in women and men with breast cancer,” he said. “In general, the hopes of androgen therapies for breast cancer are to reduce the risk of distant recurrence and increase the cure rates.”

“Our study underscores the need for improved therapies in the adjuvant setting (treatment after surgery) to reduce the risk for recurrence for men with breast cancer, particularly the risk of late recurrences,” Leone stated.

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