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

Malignant ovarian and testicular germ cell tumors: Common characteristics but different prognoses

Both ovarian and testicular germ cell tumors (GCTs) arise from the primordial germ cell and share many similarities. Both malignancies affect mainly young patients, show remarkable responsiveness to cisplatin-based therapy, and have an excellent prognosis, which also highlights the importance of minimizing long-term side effects. However, certain differences can be noted: The spreading of the disease differs, and the staging system and treatment recommendations are dissimilar. Moreover, the prognosis for ovarian GCTs is significantly inferior to that for testicular cancer, as exemplified in this review comparing the survival in Swedish patients diagnosed with testicular (1995-2022) and ovarian (1990-2018) GCTs. The 5-year overall survival in ovarian GCTs was 85.2%, versus 98.2% for testicular GCTs. How can this be explained? One reason may be the difference in knowledge, experience, and evidence because the incidence rate of testicular cancer is more than 15 times that of ovarian GCTs. Given the rarity of the disease in women and the lack of established guidelines, a comprehensive understanding of the disease and treatment decisions is challenging. The main objective of this review is to derive insights from testicular GCTs (seminoma and non-seminoma) by reviewing etiological, tumor biological, and clinical knowledge, and to thereafter suggest actions for ovarian GCTs based on this. We hypothesize that by adopting specific treatment strategies from testicular GCTs-including de-escalating adjuvant chemotherapy for low-risk patients and implementing more standardized and intensive treatment protocols in cases of relapse-we can improve the prognosis and minimize long-term side effects in ovarian GCT patients.

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

Ovarian cancer is influenced by reproductive factors, with a reduced risk of epithelial ovarian cancer in parous women. Nonepithelial ovarian cancer frequently affects young women and often precedes or occurs during the childbearing years. However, the impact of reproductive factors on ovarian cancer survival remains unclear: in epithelial ovarian cancer, data are conflicting, and subtype-specific associations have not been examined, and in nonepithelial ovarian cancer, it has not been studied. Using Swedish registers, we evaluated associations between women's reproductive history and cancer-specific mortality by subtype of epithelial and nonepithelial ovarian cancer in 3791 women born 1953 and later, diagnosed from 1990 to 2018. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated using Cox-proportional hazard models. Parity was associated with a 78% decreased risk of cause-specific mortality in 243 women with germ cell tumors (GCTs) (parous vs nulliparous, adjusted for age at diagnosis: HR: 0.22 [95% CI 0.07-0.62]), with a decreased risk with increasing number of births (per birth: HR: 0.60 [95% CI 0.38-0.95]). We found no evidence of associations between parity and cause-specific mortality among the 334 patients with sex-cord stromal tumors, nor among the 3214 patients with epithelial ovarian cancer; neither overall, nor by subtype. In conclusion, in our large, population-based study, parity was associated with a clearly better prognosis in GCTs but not in the other ovarian cancer subtypes. Future research on how hormone exposure impacts GCT development may lead to a better understanding of mechanisms affecting survival.

The association of reproductive factors with risk of non-epithelial ovarian cancer and comparison with serous ovarian cancer

OBJECTIVE

To examine the association between reproductive factors and risk of non-epithelial ovarian cancer and to compare the associations with those in serous ovarian cancer.

METHODS

From the Danish Cancer Registry, we identified all ovarian cancer cases (≥20 years old at diagnosis) of germ cell (n = 188), sex cord-stromal (n = 116), or serous (n = 4854) histology during 1982-2016. For each case, 15 age-matched female controls were selected with risk set sampling. Reproductive history was obtained from nationwide registries. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between reproductive factors and the three ovarian cancer types.

RESULTS

Compared with nulliparity, ever giving birth was associated with increased odds for germ cell tumors (OR = 1.28, 95% CI: 0.85-1.93) and decreased odds for sex cord-stromal (OR = 0.74, 95% CI: 0.44-1.26) and serous tumors (OR = 0.70, 95% CI: 0.64-0.76). Infertility decreased odds for germ cell tumors (OR = 0.63, 95% CI: 0.23-1.76) but increased odds for sex cord-stromal tumors (OR = 2.20, 95% CI: 0.89-5.43) and serous tumors (OR = 1.97, 95% CI: 1.69-2.30). Finally, use of oral contraceptives decreased the odds for all three tumor types (germ cell: OR = 0.50, 95% CI: 0.29-0.87; sex cord-stromal: OR = 0.40, 95% CI: 0.13-1.22; serous: OR = 0.50, 95% CI: 0.40-0.62).

CONCLUSIONS

Reproductive factors affected the risk of sex cord-stromal and serous ovarian cancer similarly with decreased risk associated with parity and use of oral contraceptives. Oral contraceptives also seemed to decrease the risk of germ cell tumors, whereas parity was associated with increased risk.