LAUSR

OBJECTIVE To determine the optimal duration of human chorionic gonadotrophin (hCG) surveillance following treatment for low and high risk gestational trophoblastic neoplasia (GTN) and establish whether the current surveillance protocol that recommends life-long hCG monitoring requires revision. METHODS A population-based cohort study was undertaken using a national registry, comprising patients from both tertiary trophoblastic disease treatment units in the UK (London and Sheffield). All patients who received chemotherapy for low or high risk GTN in the UK between 1958 and 2014 in London and 1973 and 2015 in Sheffield (n = 4201) were included in the study. Patients with placental site trophoblastic tumours and epithelioid trophoblastic tumours were excluded due to their distinct clinical behavior, treatment and follow-up requirements. The risk of recurrence with time following completion of chemotherapy for low or high risk GTN was measured. RESULTS The overall risk of relapse in this national cohort of 4201 patients was 4.7% (198/4201) with a median time to recurrence of 117.5 days (range 9 days to 6.54 years). The greatest risk of recurrence occurred in the first year after completing treatment for either low or high risk GTN measuring 72.7% (n = 112) or 86.4% (n = 38), respectively. The subsequent recurrence risk reduced over time with none observed beyond 7 years. CONCLUSIONS The absence of any recurrences beyond seven years following completion of chemotherapy for GTN indicates that the UK policy of life-long hCG surveillance is unnecessary. Our revised conservative protocol recommends stopping after 10 years.