title: Methadone for Patients with Malignant Psoas Syndrome: Case Series of Three Patients.
abstract: BACKGROUND
  Malignant psoas syndrome (MPS) is a relatively rare syndrome that accompanies malignancy; the pain associated with MPS is often difficult to control. Methadone is known to be effective in relieving both nociceptive and neuropathic pain.
  
  
  OBJECTIVE
  Herein we describe treatment strategies for three patients with MPS, diagnosed by imaging and clinical findings, who responded to methadone treatment.
  
  
  METHODS
  Patient diagnoses, pain characteristics, and treatment were analyzed retrospectively. Subjects were three patients with MPS who presented to Hyogo Cancer Center with pain. A numeric rating scale (NRS; 0-10) was used to assess patients' pain levels.
  
  
  RESULTS
  All three patients were diagnosed with malignancies (prostate, cervical, and urachal) and had impaired gait and thigh extension. All had tumor invasion to the iliopsoas muscle, as determined by imaging, and were diagnosed with MPS. After starting methadone, symptoms improved in all patients and they were able to extend the thigh and walk normally. The NRS scores improved by an average of -7.3 points (95% confidence interval [CI] -4.97, -9.69) on Day 14; and the average time until symptom improvement after starting methadone was 2.3 days (95% CI 1.86, 2.80).
  
  
  CONCLUSIONS
  Methadone may be considered a treatment choice for MPS patients in whom pain is difficult to control.
authors.affiliation: 1 Department of Medical Oncology, Hyogo Cancer Center , Akashi-City, Hyogo, Japan .
authors.forename: Naoto
authors.initials: N
authors.lastname: Takase
authors.affiliation: 2 Department of Palliative Medicine, Hyogo Cancer Center , Akashi-City, Hyogo, Japan .
authors.forename: Junichi
authors.initials: J
authors.lastname: Ikegaki
authors.affiliation: 3 Palliative Care Team, Hyogo Cancer Center , Akashi-City, Hyogo, Japan .
authors.forename: Harumi
authors.initials: H
authors.lastname: Nishimura
authors.affiliation: 3 Palliative Care Team, Hyogo Cancer Center , Akashi-City, Hyogo, Japan .
authors.forename: Sayoko
authors.initials: S
authors.lastname: Yuasa
authors.affiliation: 3 Palliative Care Team, Hyogo Cancer Center , Akashi-City, Hyogo, Japan .
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Ito
authors.affiliation: 4 Department of Palliative Medicine, Kobe University Graduate School of Medicine , Kobe, Hyogo, Japan .
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kizawa
mesh_terms: D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use*; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000150:complications*; D009437:Neuralgia / Q000188:drug therapy*; D016658:Psoas Muscles / Q000503:physiopathology*; D012189:Retrospective Studies; D013577:Syndrome
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone