Treatment Outcome and Chemoresistance-Related Factors of Low-Risk Gestational Trophoblastic Neoplasia: Results From a Tertiary Care Center in Saudi Arabia.

PURPOSE: Gestational trophoblastic neoplasia (GTN) is a highly curable malignancy classified using the International Federation of Gynecology and Obstetrics (FIGO)/WHO scoring system into low-risk (score 0-6) and high-risk (score ≥ 7) categories. Although single-agent chemotherapy is standard for low-risk GTN, patients with FIGO scores of 5-6 exhibit disproportionately high rates of chemoresistance, raising concerns about current classification and treatment strategies.

METHODS

This retrospective analytic study included 162 patients with low-risk GTN treated at a tertiary referral center in Saudi Arabia from 1980 to 2021. Patients were stratified into FIGO score subgroups (0-4 v 5-6), and data on demographics, treatment regimens, outcomes, and chemoresistance were collected. The primary outcome was resistance to first-line chemotherapy. Multivariable logistic regression identified independent predictors of chemoresistance.

RESULTS

The median patient age was 35 years, with 64.8% age 40 years and younger. Hydatidiform mole was the most common antecedent pregnancy (88.9%), and 30.9% had FIGO scores of 5-6. First-line treatment included single-agent chemotherapy (74.7%) and multiagent regimens (25.3%). Although all patients achieved complete remission, 26.5% exhibited chemoresistance to first-line treatment, significantly associated with treatment before the year 2000, higher FIGO scores, and single-agent chemotherapy. On multivariable analysis, FIGO scores of 5-6 (odds ratio [OR], 2.6; P = .02) and single-agent chemotherapy (OR, 0.11; P = .007) were independent predictors of resistance. β-human chorionic gonadotropin (hCG) level was the only FIGO component independently linked to chemoresistance. Relapse occurred in 5.4% of cases.

CONCLUSION

Patients with FIGO scores of 5-6 and high β-hCG levels had increased resistance to first-line therapy. β-hCG was the strongest independent predictor. These findings highlight the need to reassess treatment strategies for this subgroup.