Prognostic markers and long-term outcome of placental-site trophoblastic tumours: a retrospective observational study.

BACKGROUND: Placental-site trophoblastic tumours are a rare form of gestational trophoblastic disease and consequently information about optimum management or prognostic factors is restricted. We aimed to assess the long-term outcome of stage-adapted management by surgery, chemotherapy, or both for patients with the disorder.

METHODS: 35 550 women were registered with gestational trophoblastic disease in the UK (1976-2006), of whom 62 were diagnosed with placental-site trophoblastic tumours and included, retrospectively, in the study. Patients were treated by surgery, chemotherapy, or both. We estimated the probabilities of overall survival and survival without recurrence of disease 5 and 10 years after the date of first treatment, and calculated the association of these endpoints with prognostic factors, including time since antecedent pregnancy, serum concentration of beta-human chorionic gonadotropin, and stage of disease, with both univariate and multivariate analyses.

FINDINGS: Probabilities of overall and recurrence-free survival 10 years after first treatment were 70% (95% CI 54-82) and 73% (54-85), respectively. Patients with stage I disease had a 10-year probability of overall survival of 90% (77-100) and did not benefit from postoperative chemotherapy. By contrast, patients with stage II, III, and IV disease required combined treatment with surgery and chemotherapy; probability of overall survival at 10 years was 52% (3-100) for patients with stage II disease and 49% (26-72) for stage III or IV disease. Outcome for patients who had recurrent or refractory disease was poor: only four (22%) patients achieved long-term survival beyond 60 months. Multivariate analysis showed that the only significant independent predictor of overall and recurrence-free survival was time since antecedent pregnancy. A cutoff point of 48 months since antecedent pregnancy could differentiate between patients' probability of survival (<48 months) or death (>/=48 months) with 93% specificity and 100% sensitivity, and with a positive predictive value of 100% and a negative predictive value of 98%.

INTERPRETATION: Stage-adapted management with surgery for stage I disease, and combined surgery and chemotherapy for stage II, III, and IV disease could improve the effectiveness of treatment for placental-site trophoblastic tumours. Use of 48 months since antecedent pregnancy as a prognostic indicator of survival could help select patients for risk-adapted treatment.

FUNDING: National Commissioning Group.