Breast cancer screening in high-risk men may improve cancer detection

Screening men at high risk for developing breast cancer could potentially help detect malignant lesions at an early stage of disease, according to a retrospective observational study.

The researchers looked at data of 1,869 men aged 18–96 years (median age 55 years) at high risk of breast cancer (personal or family history of breast cancer and/or genetic mutations) who had undergone breast imaging examinations between January 2005 and April 2017 at New York University Langone Medical Center, New York, US.

All patients underwent mammography, with 48.9 percent of examinations including sonography. The number of screening and diagnostic examinations over time increased at a greater rate among men than women (p<0.001 for both). [Radiology 2019 Nov;293:282-291]

The 2,052 examinations carried out led to the detection of 2,304 breast lesions. A total of 149 biopsies were done in 133 men, which identified 41 malignant and 108 benign lesions. Thirty-eight of the malignant lesions were invasive ductal carcinomas with or without ductal carcinoma in situ.

A majority of the malignant lesions (n=36) were diagnosed at diagnostic examinations, while five node-negative cancers were diagnosed during screening examinations. The cancer detection rate via screening mammography was 18 per 1,000 examinations, while the rate from diagnostic examinations was 20 per 1,000 examinations.

The cancer detection rate via screening was higher in high-risk men than average-risk women (18 vs 3.4–5.1 per 1,000 examinations) or high-risk women (7.2–7.5 per 1,000 examinations), the researchers noted.

“Mammographic screening has helped improve the prognosis for women with breast cancer,” said study lead author Dr Yiming Gao from the Department of Radiology at New York University Langone Medical Center. “But men don’t have any formalized screening guidelines, so they are more likely to be diagnosed at a more advanced stage and often don’t do as well as women.”

“Our study shows that although such screening takes place to a limited extent (13.2 percent of examinations, 271 of 2052), it has the potential to depict clinically occult early-stage malignancy in this population, with a cancer detection profile highly comparable and superior to screening outcomes seen in women with average risk,” said the researchers.

Cancers detected during screening had a lower likelihood of being mass lesions and were more likely calcifications than cancers detected during diagnostic examinations (p=0.003 for both). Screening-detected cancers were also more likely in situ than invasive (p=0.003), less likely node positive (p=0.004), and smaller sized (average 1.2 vs 2.1 cm; p=0.003) than diagnosis-detected cancers.  

Certain factors increased the likelihood of breast cancer detection. This included older age (mean age 65.2 vs 51.4 years [men without breast cancer]; p<0.001), having a personal history of breast cancer (odds ratio [OR], 84; p<0.001) or being of Ashkenazi descent (OR, 13; p<0.001), having a first-degree relative with breast cancer (OR, 3; p=0.03), or having breast cancer-related genetic mutations (OR, 7; p=0.006).

Mammography sensitivity and specificity was high, be it for screening examinations (100 and 95 percent, respectively) or diagnostic examinations (94.7 and 92.4 percent, respectively), with the reason for the high sensitivity put down to “a relative lack of breast fibroglandular tissue” in men.

According to the researchers, the results indicate a potential benefit of selective screening, particularly in men with a prior history of breast cancer. Three of the four cancers found in this group were detected after multiple screening examinations over the years, which points to the potential importance of routine screening among men with prior breast cancer. “[A] more nuanced understanding of risk may help better direct targeted screening among men with high risk,” they added.

The single-centre and retrospective design of the study may have limited the generalizability of the findings, while bias may have been present as patients who underwent screening did so after recommendation from oncologists.

“We’ve shown that male breast cancer doesn’t have to be diagnosed only when symptomatic,” said Gao. “Rethinking our strategy toward male breast cancer diagnosis is necessary. We hope these results will provide a foundation for further investigations, and potentially help pave the way to standardizing screening for certain high-risk groups of men,” he added.