MONDAY, May 24, 2004 (HealthDayNews) -- Breast cancer in men has increased significantly over the past two and a half decades, a new study finds.
Although the rise is nowhere near as dramatic as the increase for women over the same period of time, the researchers found that the number of cases rose from 0.86 to 1.08 cases per 100,000 men. They also found that men were typically diagnosed at a later age and at a later stage of the disease than women.
Still, male breast cancer remains uncommon, representing 0.6 percent of all breast cancers and less than 1 percent of cancers in men.
The study, by researchers at the University of Texas M.D. Anderson Cancer Center in Houston, was led by Dr. Sharon Giordano, an assistant professor of breast medical oncology. It appears in the May 24 online edition of the journal Cancer.
"Because it is so rare, we haven't had good information about male breast cancer epidemiology, treatment or prognosis, Giordano said. "We had not even been able to determine previously whether the disease presents the same way in both sexes. Our examination and analysis of the National Cancer Institute's data from 1973 to 1998 has helped fill in some of those gaps in our knowledge."
The study showed that men tend to be diagnosed on average at age 67; women are diagnosed, on average, at 62. It also found that hormone status and tumor severity were not independent predictors for survival in men.
In addition, men were more likely to be diagnosed with breast cancer in their auxiliary lymph nodes and with estrogen and progesterone receptor positive tumors.
The study did not provide any clue about why male breast tumors are on the rise. But other medical experts have some ideas.
"There are at least three factors that could be associated with the increase observed," said Dr. Alison Estabrook, a breast surgeon at the Comprehensive Breast Center at St. Luke's-Roosevelt Hospital in New York City. "The first is an increase in carcinogens in the environment; the second is more awareness that males can have this type of cancer leading to more such diagnoses; and the third is the current epidemic of obesity."
Estabrook explained that increases in body fat are associated with increases in circulating estrogen, a factor associated with the development of breast cancer in both men and women.
About 1,500 men are diagnosed with breast cancer and about 400 die from it in the United States each year, said Dr. Kathleen Wilson, senior internal medicine specialist at the Ochsner Clinic Foundation in New Orleans. There is one breast cancer case diagnosed in men for every 150 in women, she said.
"Men whose families carry the breast cancer gene and have a strong family history of female breast cancer have a higher risk," said Wilson. "And men with low testosterone levels may also be at greater risk, including men with Klinefelter syndrome who have an XXY instead of the more usual XY chromosome pattern."
In her experience, breast cancer diagnosis in males usually occurs after a man finds a breast lump or experiences breast or chest wall pain, dimpled or retracted breast tissue, or nipple discharge.
"I routinely examine the breast tissue of men during their physical exams," Wilson said. "I also recommend that my male patients do regular breast self-exams while showering. Screening mammograms are not recommended for men because of the rarity of this cancer, but mammograms and biopsies are used diagnostically in men once a lump is discovered."
The recommended treatment for male breast cancer is modified radical mastectomy surgery, Wilson said.
"The lumpectomy used in women is not practical because there is so little breast tissue in men," she added. "Lymph nodes under the arm are sampled or a PET scan can show if there is cancer outside of the breast."
Men's breast cancer responds as well to treatment as women's breast cancer if the cancers are the same size and have affected the same number of lymph nodes, Wilson said.
"It was previously thought that breast cancer in men was worse than breast cancer in women, but that is probably because the cancers in males are diagnosed in a late stage because no one suspects them," she said.