Incidence and survival of rare female genital tract cancers in Europe: The EUROCARE-6 study.

Cancers of female genital tract (FGTC) account in Europe for 14 % of all female malignancies, and many of them are rare. FGTC epidemiological indicators are usually reported by anatomical site, but they are a heterogeneous group of diseases in terms of morphological characteristics and clinical management. We show incidence and survival population-based estimates and time trends in the European population for FGTC, defined combining topography and morphology codes. We analyzed data of females aged 15 years or more diagnosed with 25 FGTC of which 23 rare. Data were provided by 100 European population-based cancer registries to the EUROCARE-6 project. Incidence was estimated for the period of diagnosis 2001-2013 in terms of both crude and age-adjusted rates. Observed and relative survival was estimated with the complete approach for the period of diagnosis 2008-2013 and with the period approach for trends, considering years of follow-up from 2001 to 2014. Over a total of 793,715 considered diagnoses of FGTC, 279,667 were classified as rare entities. Their crude incidence rate per 100,000 largely varied from almost zero for adenoid cystic carcinoma of corpus uteri to 5.9 for squamous cell carcinoma of cervix uteri. During the period 2001-13, a significant increment was reported for clear cell adenocarcinoma, Mullerian mixed tumor and serous/papillary carcinoma of corpus uteri, for the Mullerian mixed tumor, adenocarcinoma of fallopian tube, and primary peritoneal serous/papillary carcinoma, and malignant/immature teratoma of ovary. Incidence rates significantly reduced for squamous cell carcinoma of cervix uteri, mucinous adenocarcinoma and sex cord tumor of ovary. Five-year relative survival was >84 % for all the non-epithelial tumors of ovary and for choriocarcinoma of placenta. Survival under 40 % was estimated for Mullerian mixed tumors and undifferentiated carcinomas of all the considered sites. Major survival improvements were observed for placenta choriocarcinoma, sex cord tumor, malignant/immature teratoma and mucinous adenocarcinoma of ovary, in adenocarcinoma of fallopian tube and in serous/papillary carcinoma of corpus uteri. Relative survival significantly reduced in squamous cell carcinoma of corpus uteri. The increasing incidence and survival of many rare FGTC can be in part attributed to better diagnostic ability and to a better organisation of care of patients with rare tumors. The epidemiological indicators here provided can be taken as a starting point to evaluate the effectiveness of the future activities of the European Rare Cancers Networks.