While breast cancer is far more common in women than in men, men may be more likely to die from early-stage breast tumors, a new study suggests.

Male breast cancer is rare, accounting for less than 1 percent of all breast cancers. But unlike the case with breast cancer in women, there have been no improvements in survival the past 30 years in men with this disease.

The rarity of breast cancer in men has prevented clinical trials, and treatment is based on what’s known about female breast cancer.

But the new findings, published in the journal Cancer, suggest that there may be biological differences in male and female breast cancers that affect survival. Specifically, men with relatively small tumors or tumors that had not yet spread to the lymph nodes had a shorter survival time than their female counterparts.

Among men whose breast cancer had not spread to the lymph nodes, the typical survival time was 6 years, compared with nearly 15 years among women.

The difference suggests a need for better understanding of male breast cancer, and improved treatments, according to Dr. Zeina A. Nahleh and her colleagues at the University of Cincinnati.

The researchers based their findings on a large cancer registry maintained by Veterans’ Affairs. They reviewed the records of 612 men treated for breast cancer and compared them with 2,413 women treated for the disease.

While Nahleh’s team found no difference in survival times of men and women with more-advanced breast cancer, they did find one among patients with earlier-stage tumors.

When it came to treatment, men had lower rates of both chemotherapy and radiation than women did, but they were as likely as women to receive hormone therapy.

Hormonal therapies for breast cancer, such as the drug tamoxifen, block the ability of estrogen to fuel tumor growth. As in women, men’s breast tumor cells often have receptors for estrogen, which means hormone therapy can be helpful.

However, Nahleh and her colleagues write, it’s possible that men’s breast tumors do not respond well to standard therapy with tamoxifen.

“A better understanding of this disease is needed,” they conclude, “so that new opportunities for therapeutic intervention may be developed.”

SOURCE: Cancer, April 15, 2007.