1 March 2001
Chemotherapy Creates Long Term Fertility Problems
by George Atkinson

In a study reflecting the growing interest in the long-term effects of cancer treatment, researchers at Dana-Farber Cancer Institute and Children's Hospital, Boston, have found that boys treated with high doses of chemotherapy are likely to experience fertility problems as adults.

The study, published in the February 1, 2001 issue of the journal Cancer, involved 17 adult males who, as children, had been treated with chemotherapy drugs known as alkylating agents for a variety of sarcomas--cancer of the bone, cartilage, or certain muscles. The drugs are known to produce fertility declines in adult cancer patients, but their long-term effect on children had not been well studied until now.

The researchers, led by Lisa Diller, M.D., a pediatric oncologist at Dana-Farber and Children's and medical director of the David B. Perini, Jr. Quality of Life Clinic at Dana-Farber, found that 10 of the study participants (60 percent of the entire group) had no sperm production, five (or 29 percent) had reduced sperm production, and only two (or 12 percent) had normal sperm counts. The two with normal sperm counts had received the lowest doses of the chemotherapy drugs. All the patients who had been treated prior to puberty had abnormalities in their semen; a finding that contradicts doctors' long-held belief that exposure to these drugs prior to puberty was safe for the male reproductive organs.

"The results indicate that exposure to alkylating agents prior to puberty is not protective, and that the risk of infertility increases with higher doses of the therapy," says Diller. "It's important that parents of young patients be informed about the potential for long-term side effects on fertility."

Alkylating agents work by destroying fast-dividing cells in the body. These include cancer cells, but also hair cells, cells in the digestive tract, and cells in the testicles that produce sperm. Because the sperm-producing cells in children have not begun to function as in adults, it hadn't been known whether chemotherapy would impair their future fertility.

Pediatric oncologists at Dana-Farber and Children's now plan several avenues of research in an effort to reduce the chances that patients will experience abnormal sperm counts later in life. Among them are: using lower doses of alkylating agents and using other chemotherapy agents that have fewer side effects on fertility. For patients who have already reached puberty, sperm banking prior to treatment may offer a chance to father children later in life, researchers say.

"We continue to search for ways to use current therapies to minimize side effects, " says study lead author Lisa Kenney, M.D., M.P.H. "The more we learn about the long-term ramifications of cancer treatments from past patients, the better we can manage patients today."

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