Failure of single dose methotrexate followed by citrovorum factor in nonmetastatic gestational trophoblastic neoplasia.

With increasing cost of medical care, newer methods of administering chemotherapy on an outpatient basis are being sought to reduce the need for hospitalization and protracted losses of valuable time for patients with nonmetastatic gestational trophoblastic neoplasia (NMGTN). To achieve this end, two NMGTN patients were treated with a single course of one dose of methotrexate (MTX) followed by multidose Citrovorum Factor (CF) without observing the expected response. Failure to respond appeared to be due to the schedule of administration. Although the dose and plasma concentrations of MTX were considered to be adequate for cell kill, fractionation--as established by conventional schedules of MTX administration--appeared necessary for response by exposing the maximum number of trophoblastic cells to inhibitory levels of MTX during the S-phase of the cell cycle.