Demographics of epithelioid trophoblastic tumour and placental site trophoblastic tumour: a 21 year UK population study

BACKGROUND: Epithelioid and placental site trophoblastic tumours are rare gestational malignancies which have little detailed information on their population incidence or risk related to maternal age.

METHODS: We performed a retrospective UK national population-based study examining all of the cases registered between 2000 and 2020 using the databases at the UK's two gestational trophoblastic treatment centres at Charing Cross Hospital in London and Weston Park Hospital in Sheffield. The data obtained was compared with the contemporary UK birth and pregnancy statistics.

RESULTS: Over the 21-year study period, there were 132 cases of ETT or PSST. PSTT comprised 57% of the cases, 30% were ETT and 13% had mixed pathology. The combined incidence of ETT and PSTT was 1:118,736 relative to live births and 1:150,872 compared to total viable conceptions. For women aged under 20 the incidence relative to live births was 1:412,488, increasing to 1:188,292 for women 30-34 years, and 1:1,426 for women aged 45 and above. The median interval from the antecedent pregnancy to the time of diagnosis was 15 months (0-288) for the PSTT patients compared to 24 months (0-336) for patients with a diagnosis of ETT.

CONCLUSIONS: ETT and PSTT are both rare diagnoses with little detailed information on their demographics. The data in this study indicates a wide range in the interval from the antecedent pregnancy to diagnosis and confirms a close relationship between increasing incidence and rising maternal age.