Trends in hysterectomy-corrected uterine cancer mortality rates during 2002 to 2015: mortality of nonendometrioid cancer on the rise?

Corpus uteri cancer is the most common gynecological malignancy in most developed countries. The disease is typically diagnosed at an early stage, is of endometrioid histologic subtype, and has a fairly good prognosis. Here, we describe hysterectomy-corrected mortality rates of corpus uteri cancer, overall and stratified by age, stage and histologic subtype. Using data from nationwide Danish registries, we calculated uncorrected and hysterectomy-corrected age-standardized mortality rates of corpus uteri cancer among women ≥35 years during 2002 to 2015. Individual-level hysterectomy status was obtained from national registries; hysterectomy-corrected mortality rates were calculated by subtracting posthysterectomy person-years from the denominator, unless hysterectomy was performed due to corpus uteri cancer. Correction for hysterectomy resulted in a 25.5% higher mortality rate (12.3/100000 person-years vs 9.8/100000 person-years). Mortality rates were highest in women aged 70+, irrespective of year of death, histologic subtype and stage. A significant decline was observed in overall hysterectomy-corrected mortality rates from 2002 to 2015, particularly among women aged 70+. Mortality rates of endometrioid cancer declined significantly over time (annual percent change [APC]: -2.32, 95% CI -3.9, -0.7, P = .01), whereas rates of nonendometrioid cancer increased (APC: 5.90, 95% CI: 3.0, 8.9, P < .001). With respect to stage, mortality rates increased significantly over time for FIGOI-IIa (APC: 6.18 [95% CI: 1.9, 10.7] P = .01) but remained unchanged for FIGO IIb-IV. In conclusion, increasing mortality rates of nonendometrioid cancer paralleled the previously observed rise in incidence rates of this histologic subtype. Given the poor prognosis of nonendometrioid cancer, more studies are needed to clarify the underlying reason for these findings.