Pregnancy-related risk factors for sex cord-stromal tumours and germ cell tumours in parous women: a registry-based study

Abstract

BACKGROUND: Non-epithelial ovarian cancers are divided into sex cord-stromal tumours (SCSTs) and germ cell tumours (GCTs). Whereas parity and other pregnancy-related factors are protective for epithelial ovarian cancer, their associations with SCSTs and GCTs remains unclear. METHODS: Using data from the medical birth registries from Denmark, Finland, Norway and Sweden, we compared all parous women with a diagnosis of SCSTs (n = 420) or GCTs (n = 345) 1970-2013 with up to 10 parous controls (SCSTs n = 4041; GCTs n = 2942) matched on the cases' birth year and country. We used conditional logistic regression to estimate odds ratios (ORs) with 95% confidence intervals (CIs) of associations between pregnancy-related factors and SCSTs and GCTs. RESULTS: The risk of SCSTs, but not GCTs, decreased with higher age at last birth [≥40 versus <25 years: OR 0.48 (95% CI 0.23-0.98)]. The risk of SCSTs (but not GCTs) also decreased with shorter time since last birth. Number of births, preterm birth, preeclampsia, and offspring size were not associated with risk of SCSTs or GCTs. CONCLUSIONS: We found a decreased risk of SCSTs with higher age at last birth and shorter time since last birth. The risk of SCSTs (but not GCTs) may be influenced by the woman's reproductive history.

Parity is associated with better prognosis in ovarian germ cell tumors, but not in other ovarian cancer subtypes

“…Although pregnancies seem to have a limited impact on the risk of these rare tumors, 26 we found that parous women diagnosed with GCTs had a clearly better prognosis than nulliparous women. To our knowledge, there are no previous studies on the prognostic impact of parity in nonepithelial ovarian cancer.…”

“…Although pregnancies seem to have a limited impact on the risk of these rare tumors, 26 we found that parous women diagnosed with GCTs had a clearly better prognosis than nulliparous women. Since it is less likely that women are young when diagnosed with a malignancy have had children before their diagnosis, the group of nulliparous women will have a low mean age at diagnosis.…”

“…33 A similar effect might be possible in the ovarian germ cells. Although pregnancies do not seem to impact the risk of developing GCTs, 26 changes in hormone levels during puberty might be of importance, as well as oral contraceptive use and factors such as body size. Another possible explanation behind the protective effect of parity could be more frequent use of fertility-sparing surgery in nulliparous than in parous women, which could potentially result in a higher risk of relapse.…”

“…7 Studies on reproductive factors and risk of nonepithelial ovarian cancer are also few and conflicting. [22][23][24][25][26][27] To our knowledge, no one has studied whether the prognosis in nonepithelial ovarian cancer is affected by parity.…”

The role of pregnancy in maternal cancer risk: Epidemiologic evidence from the Nordic Countries Linked Birth and Cancer Registries Cohort Project

“…Non-epithelial ovarian cancers are divided into sex cord-stromal tumours (SCSTs) and germ cell tumours (GCTs). We investigated the associations of pregnancy characteristics by these subtypes in the Nordic Project (49). Like our findings in epithelial ovarian cancer, the risk of SCSTs, but not GCTs, decreased with older age at first and last birth.…”