NEW YORK (Reuters Health) – For women with low-risk gestational trophoblastic neoplasia, dactinomycin given every 2 weeks had a higher complete response rate than weekly methotrexate in a multinational, phase III trial.

Despite these findings, editorialist Dr. Carol Aghajanian believes that most physicians will continue to use methotrexate as first-line therapy because short- and long-term toxicity isn’t yet established for dactinomycin. In addition, dactinomycin can cause blisters, increasing the risk of local tissue injury.

Gestational trophoblastic neoplasia is diagnosed by persistently high levels of beta-human chorionic gonadotropin (beta-hCG) following surgical removal of a hydatidiform mole.

The reported incidence of hydatidiform mole ranges from 23 to 1299 cases per 11359,000 pregnancies. Gestational trophoblastic neoplasia is diagnosed in 15% to 20% of these patients, while choriocarcinoma occurs in 1 out of 40 hydatidiform moles.

The trial, supported by grants from the National Cancer Institute, included 216 women with a World Health Organization (WHO) risk score of 0 to 6 and patients with metastatic disease (limited to lung lesions < 2 cm, adnexa, or vagina) or choriocarcinoma. They were enrolled in the study between 1999 and 2007.

The investigators, led by Dr. Raymond J. Osborne from the Odette Cancer Centre in Toronto, Canada, randomized patients to weekly intramuscular methotrexate 30 mg/m