By Joene Hendry

NEW YORK (Reuters Health) - People who survive cancer that occurs early in life appear to be 50 percent less likely to parent a child than their siblings, according to findings from a Finnish population-based study.

After parenting one child, however, cancer survivors appear only slightly less likely than their siblings to parent a second child, Dr. Laura-Maria S. Madanat, of the Finnish Cancer Registry in Helsinki, and colleagues found.

They evaluated the probability of parenthood among 11,985 male and 13,799 female individuals diagnosed with cancer between birth and age 34 years, compared with 44,611 of their siblings who had not had cancer.

Overall, males diagnosed in childhood and women diagnosed in adulthood had the lowest probability of parenthood, the investigators report in the International Journal of Cancer.

"Age at diagnosis and gender of the patient are important factors which influence sensitivity of the reproductive system to the effects of cancer treatment," Madanat told Reuters Health.

Twenty-four percent of the cancer survivors were 14 years old or younger at diagnosis. Those with central nervous system tumors had the lowest probability of parenthood, regardless of gender.

Males and females diagnosed between ages 15 and 19 (10 percent of the cancer survivors) were equally unlikely to become parents, specifically after surviving leukemia, Hodgkin lymphoma, central nervous system tumors, and germ-cell cancers.

Men and women aged 20 to 34 years at diagnosis comprised 66 percent of the cancer survivors. As noted, these women, and specifically survivors of malignant bone tumors, cancer of the thyroid, breast, cervix, uterus, stomach, colon and other soft tissues, and germ-cell cancers, were less likely to become parents than adult males.

Among young adult male survivors, the probability of parenthood was lowest after leukemia and Hodgkin lymphoma.

Notably, parenthood probability appears higher among patients treated in the last decade versus those treated in the 1970's, said Madanat, which most likely reflects "the fertility-sparing and less aggressive nature of modern treatment regimens."

Continued development of assisted reproductive technologies will likely help make parenthood a reality for an increasing number of cancer survivors, Madanat concluded.

SOURCE: International Journal of Cancer, December 2008

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