Why is the rate of testicular cancer increasing?

• Published in: Canadian Medical Association journal (CMAJ) 1999-01, Vol.160 (2), p.213-214
• Main Author: Klotz, L H
• Format: Article
• Language: English
• Subjects: Canada - epidemiology; Cancer; Environmental Exposure - adverse effects; Estrogens - adverse effects; Humans; Incidence; Life Style; Male; Population Surveillance; Risk Factors; Statistics; Testicular cancer; Testicular Neoplasms - epidemiology; Testicular Neoplasms - etiology
• ISSN: 0820-3946; 1488-2329

There has also been an increase in reports of genital abnormalities, including hypospadius, cryptorchidism and gonadal intersex abnormalities.4,5 The increased incidence of germ cell cancers among men with testicular atrophy, testicular dysgenesis, cryptorchidism and infertility suggests a common etiologic relation between germ cell cancers and these genital abnormalities. It is a reasonable hypothesis that toxins acting during the early fetal development of the gonads are involved in the reduction in testicular size and spermatogenesis rate and the increase in the incidence of testicular germ cell cancer. This hypothesis is further supported by evidence of a fetal origin of carcinoma in situ of the testis, an established precursor of testicular germ cell cancer. A recent finding supporting the relation between estrogenic exposure in utero and testicular cancer is the observation that dizygotic twins, whose maternal estrogen levels are higher than those of monozygotic twins, have a higher incidence of testicular cancer.15 The same relation was found in female twins with respect to the incidence of breast cancer, another estrogen-associated disease.15 Other factors associated with variations in intrauterine hormone levels, including birth order, increased bleeding during pregnancy and excessive nausea during pregnancy, have been associated with an increased risk of testicular cancer.16