Trends in survival of epithelial ovarian/tubal cancer by histology and socioeconomic status in Denmark 1996-2017.

OBJECTIVES: To examine time trends in ovarian/tubal cancer relative survival, excess mortality, and all-cause mortality for different histological types and levels of socioeconomic position. METHODS: Women with ovarian/tubal cancer diagnosed 1996-2017 were identified in the Danish Cancer Registry (n = 11,755). Age-standardized 5-year relative survival over time was estimated by histology, socioeconomic status, and stage. Furthermore, 5-year excess mortality rate ratios (EMRR) according to calendar time for all categories of histology and socioeconomic status were calculated using a Poisson regression model. Finally, all-cause mortality by histology and socioeconomic status was estimated in multivariate Cox proportional hazards regression models. RESULTS: Statistically significant improvements in 5-year relative survival occurred for all histological types over time except mucinous tumors (5-year EMRR, localized: 0.92 (95% CI: 0.71-1.16); advanced: 0.96 (95% CI: 0.85-1.08). Increase in relative survival over time and corresponding decrease in excess mortality was observed for all categories of socioeconomic status except for women with localized disease in the lowest income group (5-year EMRR = 0.91 (95% CI:0.76-1.10)). The impact of histology and socioeconomic status on all-cause mortality depended on time since diagnosis. Among the socioeconomic factors, especially low educational level and living alone were associated with increased all-cause mortality, particularly in the first year after diagnosis. CONCLUSIONS: Ovarian/tubal cancer survival generally increased over time across histological types and socioeconomic factors. However, the lack of improvement for mucinous tumors needs further research. Additionally, the results for women with low income and education shows that continued focus on social equality in survival is necessary.

A Danish nationwide study of risk factors associated with Type I and Type II endometrial cancer.

OBJECTIVE: To examine risk factors for Type I and Type II endometrial cancer (EC) and to directly compare the influence of risk factors for Type II with Type I tumors. Furthermore, to examine whether risk factors for high-grade Type I and Type II tumors differed from low-grade Type I tumors. METHODS: Women with EC diagnosed during 2000-2016 were identified in the Danish Cancer Registry. A case-control analysis was conducted with 1:15 random population controls matched on age and gender. Using conditional logistic regression, odds ratios and 95% confidence intervals on risk factors for Type I and II tumors were estimated. In case-case analyses, risk factors were evaluated in a direct comparison of cases grouped by tumor type and grade. RESULTS: We identified 6958 women with Type I EC and 1206 women with Type II EC. In the case-control analysis, nulliparity and diabetes were associated with increased risk of both tumor types, whereas hormone replacement therapy only increased the risk of Type I EC. When directly comparing Type I and II tumors, the influence of BMI ≥ 30, current smoking, and parity ≥ 3 was strongest for Type I EC. The associations for the majority of risk factors were similar for Type II and high-grade Type I tumors compared with low-grade Type II tumors. CONCLUSIONS: Risk factors for Type I and II tumors were overlapping suggesting that Type II tumors may be less estrogen-independent than previously anticipated. High-grade Type I tumors seemed to resemble Type II tumors more than low-grade Type I tumors.

Oral contraceptive use and impact of cumulative intake of estrogen and progestin on risk of ovarian cancer.

PURPOSE: Oral contraceptive use decreases the risk of ovarian cancer, but no previous studies have assessed the impact of cumulative intake of estrogen and progestin on ovarian cancer risk. METHODS: We used data from a population-based case­control study conducted in Denmark in 1995­1999 among women aged 35­79 years; 554 women with epithelial ovarian cancer and 1,564 age-matched controls were included in the analyses. Data were analyzed in multiple logistic regression models. RESULTS: The use of combined oral contraceptives only and the mixed use of combined and progestin-only pills decreased the risk of ovarian cancer, while no association was found with exclusive use of progestin-only pills. No major differences in risk were found for users of combined oral contraceptives with high- and low-potency estrogen and progestin. There was no effect of cumulative progestin intake, but decreased risks of ovarian cancer with increasing cumulative intake of estrogen (OR = 0.82; 95 % CI 0.67­0.99, per 100 mg estrogen) and increasing duration of oral contraceptive use (OR = 0.95; 95 % CI 0.92­0.98, per year of use) were found. No effect of cumulative estrogen intake was found, however, after adjustment for duration of oral contraceptive use. CONCLUSIONS: The protective effect of oral contraceptives against ovarian cancer may be sufficiently explained by duration of anovulation. This suggests that if the estrogen and progestin doses are sufficient to cause anovulation, a higher intake of estrogen or progestin confers no extra protection against ovarian cancer.