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ale breast cancer is a relatively rare disease. For this
reason, very few studies have evaluated the factors that have associations with
better outcomes. A fresh investigation begins to fill this gap.
Male breast cancer is rare but understudied.
Male breast cancer (MBC)
accounts for just 1% of all breast cancer cases.
However, some scientists believe that prevalence has risen over
the last few decades.
Scientists have also spotted differences between the tumor biology in MBC
and breast cancer in women.
They have also noted other differences between female breast
cancer and MBC. For instance, MBC tends to occur later in life, and it more
commonly moves into lymph nodes, making it harder to treat.
Taken together, these factors may mean that treatment aimed
at more common forms of breast cancer are not as effective against MBC.
Male breast cancer examined
Although the treatment of breast cancer has improved
dramatically over recent years, as the authors of the latest study explain,
"it is unclear whether these advances have been applied to the management
of MBC."
Researchers from Mayo Clinic in Rochester, MN, set out to
understand how doctors treat MBC in the United States, and what factors might
lead to better outcomes.
They conducted one of the largest studies to investigate MBC
to date, and recently published their results in the journal Cancer.
To investigate, the scientists accessed data from the
National Cancer Database. They scrutinized the records of men diagnosed with
stage 1–3 breast cancer from 2004–2014. In total, the study included data from
10,873 men.
The average age of diagnosis was
64, and 51% of diagnoses occurred between the ages of 50 and 69. Only 15%
received a diagnosis before the age of 50.
They found that 24% of men had breast-conserving surgery and
that 70% of these men received radiation therapy.
They also showed that 44% of people with MBC received chemotherapy, and 62% of
those whose tumors expressed the estrogen receptor
received anti-estrogen therapy.
Over the 10 years, the researchers noted a steady increase
in the rates of total mastectomy and contralateral
prophylactic mastectomy, which is when a surgeon removes a healthy breast as a
preventive measure.
They also measured an increase in genomic testing on tumors
and a rise in the use of anti-estrogen therapy.
Factors associated with poorer
outcomes
The authors of the study wanted to understand which factors
might predict worse health outcomes.
They found that prognosis was
poorer for black men, older patients, individuals with ongoing health issues
other than MBC, and those with higher tumor grade and stage.
Also, those who underwent a full mastectomy had poorer
outcomes. However, as the authors explain, this might be "due to the
overrepresentation of patients with larger tumors and [or] lymph node-positive
disease in this group."
Conversely, the prognosis was better for men who lived in
high income areas, those whose tumors carried the progesterone receptor,
and men who received radiation, anti-estrogen therapy, or chemotherapy.
"The racial, economic, and
age-related health disparities we found could inform future efforts to target
interventions to optimize outcomes in men with breast cancer."
Corresponding author Dr. Kathryn
Ruddy
The authors do note certain limitations to their study. For
instance, the researchers did not have access to the names of the drugs that
doctors prescribed, and they could not always ascertain whether the cancer returned following treatment.
Also, some of the subgroups only contained small numbers of
participants, such as those with tumors that lacked estrogen receptors; this
makes some of the findings more difficult to generalize.
However, as the largest study of its type, the authors hope
that their findings might guide doctors who are treating men with breast
cancer. They also hope that the paper will inspire future research into this
poorly understood disease.
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