A study of Norwegian men has revealed several factors that may help predict reproductive problems among males diagnosed with cancer before age 25.
Cancer type, age at diagnosis, and time period of diagnosis were all associated with the likelihood of paternity.
And although cancer survivors were less likely to reproduce and more likely to use assisted reproductive technology, their first offspring were no less healthy than the offspring of control subjects.
This research was published in the British Journal of Cancer.
The study began with all Norwegian men born between 1965 and 1985 (n=626,495). The researchers excluded men who emigrated or died before reaching fertile age, which left 2687 men who were diagnosed with cancer before age 25 and 607,668 cancer-free controls.
The most common cancers were testicular cancer (27%), CNS tumors (18%), lymphoma (15%), and leukemia (13%). Thirty percent of the cancer cases were diagnosed in childhood (0–14 years of age), 26% in adolescence (15–19 years), and 43% in young adulthood (20–24 years).
Nine percent (n=247) of cancer cases were diagnosed from 1965 through 1979, 50% (n=1346) from 1980 through 1994, and 41% (n=1094) from 1995 through 2007.
The cancer survivors were less likely to have children than controls, with a hazard ratio (HR) of 0.72.
The reduction in paternity was significant for survivors of leukemia (HR=0.78), lymphoma (HR=0.78), testicular cancer (HR=0.77), CNS tumors (HR=0.45), bone tumors (HR=0.69), sympathetic nervous system tumors (HR=0.50), and retinoblastoma (HR=0.52).
The reduction in paternity was also more pronounced for cancer patients diagnosed before 1995. The HR was 0.61 for those diagnosed from 1965 through 1979 and 0.66 for those diagnosed from 1980 through 1994.
Patients who were diagnosed before age 15 were less likely to reproduce as well, with an HR of 0.59.
“These finds are important for male cancer survivors, seeing as we can identify groups at risk of having reproduction problems,” said study author Maria Winther Gunnes, a PhD candidate at the University of Bergen in Norway.
Another finding was that male cancer survivors were more likely than controls to have pregnancies resulting from assisted reproductive technology. The relative risk was 3.32.
When assessed by cancer type, the relative risk was 2.29 for leukemia, 3.79 for lymphoma, 2.41 for CNS tumors, 5.71 for sympathetic nervous system tumors, 2.20 for renal tumors, 4.77 for bone tumors, 1.32 for soft tissue sarcomas, 3.70 for testicular cancer, 4.36 for thyroid carcinoma, and 0.45 for malignant melanoma.
There was no increased risk among the first offspring of cancer survivors for perinatal death, congenital malformations, being small for gestational age, low birth weight, or preterm birth.
“It is important to be able to assure young male cancer survivors that their illness and treatment will not have a negative impact on their own children,” Gunnes said.
