SAN ANTONIO – Male breast cancers share some important characteristics with female breast cancers: The tumors found in males are usually hormone receptor positive and of luminal A subtype, and respond less favorably if estrogen and progesterone receptor negative.
And like female breast cancers, both overall and breast cancer–specific survival rates have been increasing over the last 20 years, although not to the extent of survival improvements in women, Dr. Fatima Cardoso said at the San Antonio Breast Cancer Symposium.
Dr. Cardoso of the European School of Oncology Breast Cancer Program, Lisbon, presented the initial findings of the Male Breast Cancer International Program, a project intended to identify, characterize, and improve treatment for male breast cancers. The retrospective joint analysis is the first part of the three-step study, she said. In addition to identifying patients in the 10 countries involved (in the United States, western Europe, and Scandinavia), step one includes a collection of tumor blocks for central analysis in labs in the United States and the Netherlands.
Step two, already underway, is building a prospective international registry of all male breast cancer cases in the most recent 30 months of the study, including collection of tumor samples and blood, and a quality of life substudy.
Step three will comprise randomized treatment trials, one of which is “far along in the planning stage,” Dr. Cardoso said.
The retrospective cohort comprised 1,822 men who were diagnosed and treated for breast cancer from 1990 to 2010, with tumor assessments available for 1,483. About two-thirds of the men were older than 50 years; 25% were 75 or older. Just 2% were younger than 40 years.
Most cancers (71%) were local. Almost 60% were node negative, and 30% positive for one node. Two nodes were involved in 5% and the rest had three involved.
Breast-conserving surgery was the most common primary treatment (96%), with 4% undergoing a modified radical mastectomy. Three-fourths underwent both a sentinel node biopsy and axillary dissection; 18% had a sentinel node biopsy only, and the rest had no nodal investigation. There was a slight trend over the study period for more sentinel node biopsies alone, and less axillary dissection, but the number of men without an investigation stayed steady.