Objectives: The aim of the present prospective study was to identify possible risk factors of testicular cancer (TC) in relation to gestation and birth.
Methods: Based on data from compulsory birth and cancer registration in Norway, odds ratios (ORs) of TC were estimated.
Results: Among 868068 males born between 1967 and 1995, 268 cases of germ cancer had developed by June 1996, 32 TCs before 5 years of age and 236 TCs thereafter, 48 cases being seminomas and 220 non-seminomas. There was a tendency of an inverse association between parity and TC. A previous finding from Sweden linking neonatal jaundice to risk of non-seminomas was confirmed (adjusted OR = 2.1, 95 percent confidence interval [CI] = 1.3-6.9). Significant associations were also seen for seminomas and TC diagnosed after 5 years of age. Maternal disease diagnosed before pregnancy increased the risk of TC significantly, particularly in the age group 0-4 years: Adjusted OR = 3.0, CI = 1.4-6.3. Retained placenta was significantly associated with both seminomas and non-seminomas and with TC diagnosed after 5 years of age.
Conclusions: The findings of this study support the existing hypothesis that pre- and perinatal risk factors are of significance for development of TC in children and in young adults, and for seminomas and non-seminomas. The hypothesis that estrogens are involved in TC development was, among other factors, supported by the association of parity to TC. Additionally, on the basis of findings in maternal diseases and complications to pregnancy, we suggest that immune reactions during foetal life may be of significance for development of TC.