Resistance to single‐agent chemotherapy and its risk factors in low‐risk gestational trophoblastic neoplasms

• Published in: The journal of obstetrics and gynaecology research Vol. 41; no. 5; pp. 776 - 783
• Main Authors: Mousavi, Azam Sadat, Zamani, Ashraf, Khorasanizadeh, Faezeh, Gilani, Mitra Modarres, Zendehdel, Kazem
• Format: Journal Article
• Language: English
• Published: Australia 01.05.2015
• Subjects: Adolescent; Adult; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Case-Control Studies; chemotherapy; Cyclophosphamide - therapeutic use; Dactinomycin - therapeutic use; Drug Resistance, Neoplasm; Etoposide - therapeutic use; Female; gestational trophoblastic disease; Gestational Trophoblastic Disease - drug therapy; Humans; International Federation of Gynecology and Obstetrics; Iran; Methotrexate - therapeutic use; Middle Aged; Pregnancy; resistance; Risk Factors; Vincristine - therapeutic use; Young Adult; International Federation of Gynecology and Obstetrics; chemotherapy; resistance; gestational trophoblastic disease
• ISSN: 1341-8076; 1447-0756
• DOI: 10.1111/jog.12613

Aim Gestational trophoblastic neoplasm (GTN) is a rare disease which is classified into high‐ and low‐risk groups. While the high‐risk patients require combination therapy, the low‐risk groups respond to single‐agent chemotherapy. We studied resistance to single‐agent chemotherapy and its risk factors among the low‐risk GTN patients in Iran. Methods We followed 168 low‐risk GTN patients who were treated between 2001 and 2011 in Valiasr Hospital, Tehran, Iran. We used a case–control design and studied odds ratios (OR) and corresponding 95% confidence intervals (CI) to evaluate association between drug resistance and different personal and clinical variables. Results Resistance to sequential single‐agent chemotherapy was 19%, although all patients had a complete remission after a combination of chemotherapy and/or surgery. Patients who had International Federation of Gynecology and Obstetrics scores of 5–6 – considered as, the intermediate risk group – had a 14‐fold higher resistance compared with the low score patients (OR = 14.28, 95% CI = 5.54–36.81). We found higher risk of resistance among patients with metastasis (OR = 8.42, 95% CI = 2.44–29.07), large tumor size (>3 cm) (OR = 7.73, 95% CI = 1.93–30.91), high β‐hCG (>100 000 IU/L) (OR = 5.86, 95% CI = 1.07–32.02) and/or a diagnosis more than 4 months after pregnancy (OR = 3.30, 95% CI = 1.08–10.02), compared with their reference group. We found no priority for the different chemotherapy regimens. Conclusion Intermediate risk GTN patients had a higher risk of resistance to chemotherapy compared with low‐risk patients. Clinical trials and cost‐effectiveness studies are needed to suggest a better treatment program for the intermediate risk group.