Intensified therapies improve survival and identification of novel prognostic factors for placental-site and epithelioid trophoblastic tumours.

BACKGROUND

Placental-site trophoblastic (PSTT) and epithelioid trophoblastic tumours (ETT) are the rarest malignant forms of gestational trophoblastic disease (GTD). Our prior work demonstrated that an interval of ≥48 months from the antecedent pregnancy was associated with 100% death rate, independent of the stage. Here, we assess whether modified treatments for these patients have increased survival and identify new prognostic factors.

METHODS

The United Kingdom GTD database was screened to identify all PSTT/ETT cases diagnosed between 1973 and 2014. Data and survival outcomes from our prior patient cohort (1976-2006) were compared to our new modern cohort (2007-2014), when intensified treatments were introduced.

RESULTS

Of 54,743 GTD patients, 125 (0.23%) were diagnosed with PSTT and/or ETT. Probability of survival at 5 and 10 years following treatment was 80% (95% CI 72.8-87.6%) and 75% (95% CI 66.3-84.3%), respectively. Univariate analysis identified five prognostic factors for reduced overall survival (age, FIGO stage, time since antecedent pregnancy, hCG level, mitotic index) of which stage IV disease (HR 6.18, 95% CI 1.61-23.81, p = 0.008) and interval ≥48 months since antecedent pregnancy (HR 14.57, 95% CI 4.17-50.96, p < 0.001) were most significant on multivariable analysis. No significant differences in prognostic factors were seen between the old and new patient cohort. However, the new cohort received significantly more cisplatin-based and high-dose chemotherapy, and patients with an interval ≥48 months demonstrated an improved median overall survival (8.3 years, 95% CI 1.53-15.1, versus 2.6 years, 95% CI 0.73-4.44, p = 0.·005).

CONCLUSION

PSTT/ETT with advanced FIGO stage or an interval ≥48 months from their last known pregnancy have poorer outcomes. Platinum-based and high-dose chemotherapy may help to improve survival in poor-prognosis patients.