title: Comparison of 5-day MTX and 5-day ETP treatment results and early predictors of drug resistance to 5-day MTX in patients with post-molar low-risk gestational trophoblastic neoplasia.
abstract: OBJECTIVE
  To determine the primary remission rates and predictors of drug resistance in patients with post-molar low-risk gestational trophoblastic neoplasia (GTN) who were treated with a 5-day intramuscular methotrexate (5-day IM MTX) or a 5-day drip infusion etoposide (5-day DIV ETP) regimen.
  
  
  METHODS
  Between 1980 and 2014, 166 consecutive patients with low-risk post-molar GTN were initially treated with a 5-day IM MTX or a 5-day DIV ETP regimen. The primary remission rates, changes in chemotherapy due to drug resistance or toxicity, and relapse rates were compared. Furthermore, we analyzed the factors that influenced the development of resistance to MTX.
  
  
  RESULTS
  Primary remission rates were significantly higher among the ETP-treated patients than among the MTX-treated patients. Among the 42 patients who required a change in chemotherapy, 23 patients (22.6%) and 4 patients (6.3%) were diagnosed as being resistant to MTX and EPT, respectively. Maternal age and the presence of metastasis did not significantly influence the development of MTX resistance, although higher FIGO scores and pre-treatment human chorionic gonadotropin (hCG) levels of >5×10(4)mIU/mL were significantly more common among patients who developed MTX resistance. Moreover, a <30% decrease in hCG after the first cycles of MTX chemotherapy was significantly associated with the development of MTX resistance.
  
  
  CONCLUSIONS
  All patients with low-risk GTN eventually achieved complete remission, although several patients developed drug resistance to the first-line chemotherapy. A <30% decrease in hCG during the first chemotherapy cycle may be an early indicator of drug resistance after commencing a 5-day MTX regimen.
authors.affiliation: Department of Obstetrics & Gynecology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinnjuku-ku, Tokyo 162-8666, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Kizaki
authors.affiliation: Department of Obstetrics & Gynecology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinnjuku-ku, Tokyo 162-8666, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Hashimoto
authors.affiliation: Department of Obstetrics & Gynecology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinnjuku-ku, Tokyo 162-8666, Japan. Electronic address: matsui.hideo@twmu.ac.jp.
authors.forename: Hideo
authors.initials: H
authors.lastname: Matsui
authors.affiliation: Department of Reproductive Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Usui
authors.affiliation: Department of Reproductive Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
authors.forename: Makio
authors.initials: M
authors.lastname: Shozu
mesh_terms: D000328:Adult; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage* / Q000009:adverse effects; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage* / Q000009:adverse effects; D006063:Chorionic Gonadotropin / Q000097:blood; D004334:Drug Administration Schedule; D019008:Drug Resistance, Neoplasm; D057915:Drug Substitution; D005047:Etoposide / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D006828:Hydatidiform Mole / Q000097:blood / Q000188:drug therapy* / Q000556:secondary; D008727:Methotrexate / Q000008:administration & dosage* / Q000009:adverse effects; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy*; D011247:Pregnancy; D012189:Retrospective Studies; D016896:Treatment Outcome; D014594:Uterine Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D055815:Young Adult
chemical_list: D000964:Antimetabolites, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D006063:Chorionic Gonadotropin; D005047:Etoposide; D008727:Methotrexate
keywords: Chemotherapy; Drug resistance; Low-risk gestational trophoblastic neoplasia