Predictors of chemotherapy resistance & relapse in gestational trophoblastic neoplasia

BACKGROUND & OBJECTIVES: Gestational trophoblastic neoplasia (GTN) is a chemosensitive malignancy with an excellent cure rate. The primary objective of the present study was to determine the predictors of chemoresistance and disease relapse, and the secondary objective was to appraise the WHO/FIGO risk scoring and course of disease in women with GTN. METHODS: In this retrospective study, case records of women treated for GTN from January 2011 to June 2019 were reviewed. For the purpose of comparison, sub-stratification of FIGO/WHO low risk group (≤6) into low (0-4) and intermediate (5-6) risk was done. Similarly, WHO high risk (≥7) group was sub-stratified into high (7-12) and ultra-high risk (≥13) groups. RESULTS: Case records of 116 patients were included: 51.7 per cent (60/116) were of low risk disease and 48.2 per cent (56/116) were of high risk disease. Chemoresistance developed in 28.4 per cent (33/116) and relapse in 10.3 per cent (12/116) cases. Risk of chemoresistance was higher in low risk (0-6) while risk of relapse was more in high risk (≥7) group. On sub-stratification, chemoresistance was more with intermediate [0-4: 28.5% (10/35), 5-6: 44% (11/25), 7-12: 22.5% (9/40), ≥13: 18.7% (3/16)] and relapse with ultra-high risk score [0-4: 5.7% (2/35), 5-6: 4% (1/25), 7-12:10% (4/40), ≥13: 31.2% (5/16)]. Age, myometrial invasion, serum beta-human chorionic gonadotropin and tumour size were not related to chemoresistance or relapse. INTERPRETATION & CONCLUSIONS: WHO risk score and presence of metastatic disease predict the probability of developing chemotherapy resistance and disease relapse. Risk of chemotherapy resistance was higher in women with intermediate-risk score (5-6), and risk of relapse was more in those with ultra-high risk score (≥13).