The differences between male and female breast cancers have been discovered – and this could change the way that doctors treat men with the disease, a conference heard.
An international study found that the development of fibrotic connective tissue and the density of tumour infiltrating lymphocytes were strongly associated with outcomes in male breast cancer, whereas tumour grade, a commonly used prognostic measure in female breast cancer, was not.
Dr Carolien van Deurzen, a pathologist specialising in breast cancer at the Erasmus Medical Centre, Rotterdam, The Netherlands, revealed the results of a trial at the 10th European Breast Cancer Conference (EBCC-10) in Amsterdam yesterday (10 March).
The study – part of the International Male Breast Cancer Program, led by the European Organisation for Research and Treatment of Cancer (EORTC) in Europe and the Translational Breast Cancer Research Consortium (TBCRC) in the USA – examined 1,203 tumour samples from male breast cancer patients.
The team found that the lack of association between grading and outcome in men is the different distribution of breast cancer subtypes in male patients.
While lobular tumours are common in women, they are rare among men. The majority of male cancers were luminal, or oestrogen-receptor positive, whereas HER2 positive and triple negative subtypes are more common in women.
“However, this sub-typing of breast tumours does not seem to result in an optimal risk classification for male BC patients,” said Dr van Deurzen.
“Additional tests that are well established in women, including gene-expression profiling, may result in the identification of more accurate prognostic and predictive markers. These could enable us to take better treatment choices, individualised for each patient, particularly in regard to the use of chemotherapy and new targeted agents.”
The researchers hope to begin a clinical trial that uses a new agent to block the androgen receptor, a protein that is often present in male breast cancer.
“In the meantime, we believe that our findings will help focus research in the field, since they indicate that we should be focusing on improving the management of luminal cancers as opposed to other subtypes in these patients,” added Dr van Deurzen.
Abstract no. 7, “Pathologic prognostic factors of male breast cancer: results of the EORTC 10085/TBCRC/BIG/NABG International Male Breast Cancer Program”.
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