Male breast cancers are not identical to female breast cancers and male patients are not as well managed as female ones, a new study has found.
The study, which included 1,822 men treated for breast cancer between 1990 and 2010 in Europe and US, found significant improvement in survival for men with breast cancer, but this improvement was not as good as that observed for women.
“This study aims to characterise the biology of this rare disease; only with this crucial knowledge will men with breast cancer be properly treated in the future, which will definitely improve both their survival and quality of life,” said Dr Fatima Cardoso of the Champalimaud Clinical Center in Lisbon and coordinator of the study.
Even though it is considered a rare disease, male breast cancer remains frequently lethal. In 2013, estimates indicated just 2,240 new cases of male breast cancer in the US yet, alarmingly, 410 deaths.
Currently, treatment strategies for men afflicted with this disease are based on those that have been used successfully for women, and research on the differences between men and women regarding the characteristics of this disease was sorely needed, researchers said.
In the new research, the European Organisation for Research and Treatment of Cancer (EORTC), Translational Breast Cancer Research Consortium (TBCRC), Breast International Group (BIG), and the North American Breast Cancer Groups (NABCG) joined forces to launch International Programme on Male Breast Cancer.
The results of the study showed that male breast cancers are not identical to female breast cancers, and that men are not as well managed as female patients.
For example, although the majority of male breast cancers are estrogen receptor (ER) positive, only 77 per cent of male patients with this disease received hormonal therapy such as Tamoxifen, and despite the fact that slightly over half of all male breast cancers are diagnosed when the tumours are very small, only four per cent of male breast cancer patients received breast-conserving surgery.
The majority underwent mastectomies, a treatment decisions that can adversely affect quality of life, self-esteem and sexuality.
Analyses of tumour samples showed that 99 per cent of male breast cancers were ER positive, seven per cent were human epidermal growth factor receptor 2 (HER2) positive, and one per cent were triple negative, meaning that they do not express the genes for ER, progesterone receptor (PR), or HER-2, and consequently do not respond to hormonal therapy nor anti-HER-2 therapies.
For women, on the other hand, roughly 70 per cent of breast cancers are ER-positive, 20 per cent are HER2-positive, and 10 to 15 per cent are triple-negative.
The results were presented at the 2014 San Antonio Breast Cancer Symposium.