title: Determinants of opioid efficiency in cancer pain: a comprehensive multivariate analysis from a tertiary cancer centre.
abstract: BACKGROUND
  Pain is one of the most terrifying symptoms for cancer patients. Although most patients with cancer pain need opioids, complete relief of pain is hard to achieve. This study investigated the factors influencing persistent pain-free survival (PPFS) and opioid efficiency.
  
  
  METHODS
  A prospective study was conducted on 100 patients with cancer pain, hospitalized at the medical oncology clinic of Akdeniz University. Patient records were collected including patient demographics, the disease, treatment characteristics, and details of opioid usage. Pain intensity was measured using a patient self-reported visual analogue scale (VAS). The area under the curve (AUC) reflecting the pain load was calculated from daily VAS tables. PPFS, the primary measure of opioid efficacy, was described as the duration for which a patient reported a greater than or equal to two-point decline in their VAS for pain. Predictors of opioid efficacy were analysed using a multivariate analysis.
  
  
  RESULTS
  In the multivariate analysis, PPFS was associated with the AUC for pain (Exp (B)=0.39 (0.23-0.67), P=0.001), the cumulative opioid dosage used during hospitalisation (Exp (B)=1.00(0.99-1.00), P=0.003) and changes in the opioid dosage (Exp (B)=1.01 (1.00-1.01), P=0.016). The change in VAS score over the standard dosage of opioids was strongly associated with current cancer treatment (chemotherapy vs. others) (β=-0.31, T=-2.81, P=0.007) and the VAS for pain at the time of hospitalisation (β=-0.34, T=-3.07, P= 0.003).
  
  
  CONCLUSIONS
  The pain load, opioid dosage, concurrent usage of chemotherapy and initial pain intensity correlate with the benefit received from opioids in cancer patients.
authors.affiliation: Kayseri State Hospital of Research and Education, Department of Medical Oncology, Kayseri, Turkey E-mail : semasezgingoksu@gmail.com.
authors.forename: Sema Sezgin
authors.initials: SS
authors.lastname: Goksu
authors.forename: Hakan
authors.initials: H
authors.lastname: Bozcuk
authors.forename: Mukremin
authors.initials: M
authors.lastname: Uysal
authors.forename: Ece
authors.initials: E
authors.lastname: Ulukal
authors.forename: Seren
authors.initials: S
authors.lastname: Ay
authors.forename: Gaye
authors.initials: G
authors.lastname: Karasu
authors.forename: Turker
authors.initials: T
authors.lastname: Soydas
authors.forename: Hasan Senol
authors.initials: HS
authors.lastname: Coskun
authors.forename: Mustafa
authors.initials: M
authors.lastname: Ozdogan
authors.forename: Burhan
authors.initials: B
authors.lastname: Savas
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D019540:Area Under Curve; D018572:Disease-Free Survival; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000150:complications* / Q000188:drug therapy; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D059408:Pain Management; D010147:Pain Measurement; D011446:Prospective Studies; D062606:Tertiary Care Centers
chemical_list: D000701:Analgesics, Opioid; D000970:Antineoplastic Agents