BOSTON — As new treatments for cancer are developed and old ones improved, more and more victims of the disease are surviving and going on to lead near-normal lives.
There are estimated to be at least 45,000 adults living in the United States who were diagnosed with childhood cancer between 1955 and 1979, the result of a sharp increase in the survival rate of victims of childhood cancer.
But the treatment that cured the victims can leave its mark behind, especially among children and teen-agers who have many years left in their lives after winning their battles with cancer.
A new study conducted by the National Cancer Institute examined the effect of cancer treatment on fertility.
"The results of the study have broad implications for the choice of treatment not only for cancer but also for noncancerous diseases that (currently) use anti-cancer treatments," said Dr. Julianne Byrne, who headed the study.
The study, the largest of its kind, involved 2,283 survivors of childhood and adolescent cancer diagnosed from 1945 to 1975 who had undergone radiation, surgery, chemotherapy or a combination of these treatments and were now married or living with someone. They were compared to 3,270 of their siblings to determine if there was any significant difference in their fertility.
The researchers found that former cancer patients were only 85% as likely as their siblings to either have been pregnant or have fathered a child. Men were more likely than their female counterparts to have fertility problems.
When the researchers examined the types of cancer involved, only two--Hodgkin's disease and genital cancer--were significantly associated with a loss of fertility.
But the impact on fertility varied considerably depending on the type of treatment involved.
Surgery was the least harmful treatment overall, reducing fertility 9% for males and females combined. For females, it reduced fertility 2%. For males, it was 19%.
For women, surgery was the least damaging while radiation below the diaphragm was the treatment most damaging, resulting in a 22% reduction.
The least damaging treatment for males was radiation alone when given above the diaphragm. It resulted in an 11% loss of fertility.
The most damaging was chemotherapy with drugs that affect genetic material combined with radiation below the diaphragm, which reduced male fertility 62%.
Radiation was less harmful when given above the diaphragm, reducing fertility 12%, compared to a 24% reduction when radiation was given below the diaphragm. The effects of radiation were similar for males and females.
Chemotherapy with drugs that affect genetic material was more harmful to males than radiation, reducing fertility by 58%. On the other hand, the drugs appeared to have no detectable effect on female fertility for young patients during the years studied.
"This study and others highlight the considerable differences that exist in the rate of serious side effects, such as infertility, that can accompany cancer therapy," the researchers said in reporting their findings in the New England Journal of Medicine.
"Counseling of patients with cancer and their families about the risk of side effects should take into account the sex of the patient, the type of cancer and the type of treatment available. Tailoring the risk estimates to individual circumstances will help patients and physicians deal more effectively with the consequences of disease," they said.