RESUMO
Sugeriu-se que anomalias do trato reprodutivo masculino como hipospádia e criptorquidismo, assim como o câncer de testículo, componham uma síndrome comum com diminuição da espermatogênese, e de etiologia comum, a interrupção do desenvolvimento gonadal na fase fetal, a síndrome de disgenesia testicular (SDT). O único levantamento quantitativo da relação entre exposição pré-natal a agentes estrogênicos e câncer de testículo data de mais de dez anos; outras revisões da relação entre compostos estrogênicos diferentes do potente estrogênio sintético dietilstilbestrol (DES) e SDT continuam inconclusivas. Foi feita uma meta-análise quantitativa da relação entre SDT e exposição pré-natal a agentes estrogênicos. A inclusão na análise baseou-se em critérios mecanísticos e foi explorada a plausibilidade de um modo de ação mediada pelo receptor estrogênico-α (REα). Incluíram-se oito estudos sobre a etiologia das hipospádias e/ou criptorquidismo não identificados em revisões sistemáticas anteriores. Mais quatro estudos sobre estrogênios sintéticos resultaram em uma estimativa estatisticamente significativa para câncer de testículo. Os resultados das análises dos subconjuntos apontam à existência de fontes não identificadas de heterogeneidade entre estudos ou populações estudadas.
Male reproductive tract abnormalities such as hypospadias and cryptorchidism, and testicular cancer have been proposed to comprise a common syndrome together with impaired spermatogenesis with a common etiology resulting from the disruption of gonadal development during fetal life, the testicular dysgenesis syndrome (TDS). The only quantitative summary estimate of the link between prenatal exposure to estrogenic agents and testicular cancer was published over 10 years ago; other reviews of the link between estrogenic compounds, other than the potent pharmaceutical estrogen diethylstilbestrol (DES), and TDS end points have remained inconclusive. We conducted a quantitative meta-analysis of the association between the end points related to TDS and prenatal exposure to estrogenic agents. Inclusion in this analysis was based on mechanistic criteria, and the plausibility of an estrogen receptor (ER)-α-mediated mode of action was specifically explored. Eight studies were included, investigating the etiology of hypospadias and/or cryptorchidism that had not been identified in previous systematic reviews. Four additional studies of pharmaceutical estrogens yielded a statistically significant updated summary estimate for testicular cancer. Results of the subset analyses point to the existence of unidentified sources of heterogeneity between studies or within the study population.
RESUMO
Male reproductive tract abnormalities such as hypospadias and cryptorchidism, and testicular cancer have been proposed to comprise a common syndrome together with impaired spermatogenesis with a common etiology resulting from the disruption of gonadal development during fetal life, the testicular dysgenesis syndrome (TDS). The only quantitative summary estimate of the link between prenatal exposure to estrogenic agents and testicular cancer was published over 10 years ago; other reviews of the link between estrogenic compounds, other than the potent pharmaceutical estrogen diethylstilbestrol (DES), and TDS end points have remained inconclusive. We conducted a quantitative meta-analysis of the association between the end points related to TDS and prenatal exposure to estrogenic agents. Inclusion in this analysis was based on mechanistic criteria, and the plausibility of an estrogen receptor (ER)-alpha-mediated mode of action was specifically explored. Eight studies were included, investigating the etiology of hypospadias and/or cryptorchidism that had not been identified in previous systematic reviews. Four additional studies of pharmaceutical estrogens yielded a statistically significant updated summary estimate for testicular cancer. Results of the subset analyses point to the existence of unidentified sources of heterogeneity between studies or within the study population.