title: Neutropenic event risk and impaired chemotherapy delivery in six European audits of breast cancer treatment.
abstract: OBJECTIVE
  The aims of this study were to assess chemotherapy treatment characteristics, neutropenic event (NE) occurrence and related risk factors in breast cancer patients in Western Europe.
  
  
  METHODS
  Six retrospective audits of breast cancer chemotherapy were combined into a dataset of 2,860 individuals. NEs were defined as neutropenia-related hospitalisation, dose reduction > or = 15% or dose delay > or = 7 days. Summation dose intensity (SDI) was calculated to compare different types of chemotherapy regimens on a single scale. Risk factors of NE occurrence and of low relative dose intensity (RDI) < or = 85% were identified by multiple logistic regression.
  
  
  RESULTS
  Patient populations were comparable between audits. Until 1998, cyclophosphamide, methotrexate and fluorouracil regimens were most frequently used, but thereafter, anthracycline-based regimens were most common. NEs occurred in 20% of the patients and low RDI in 16%. NE occurrence predicted low RDI and was associated with higher age, bigger body surface area, lower body mass index, regimen type, more chemotherapy cycles planned, normal to high SDI, concomitant radiotherapy and year of treatment. First cycle NE occurrence predicted NEs from cycle 2 onwards. A risk score using age, SDI, number of planned chemotherapy cycles and concomitant radiotherapy differentiated patients with increasing NE risk (9-37%). An alternative score version not using concomitant radiotherapy performed moderately less well.
  
  
  CONCLUSIONS
  NEs occurred frequently in this combined dataset and they affected treatment delivery. Identifying patients at high NE risk enables targeted prophylaxis and may avoid dose limitations.
authors.affiliation: European Center of Pharmaceutical Medicine, University of Basel, University Hospital, Basel, Switzerland. m.schwenkglenks@unibas.ch
authors.forename: Matthias
authors.initials: M
authors.lastname: Schwenkglenks
authors.forename: Christian
authors.initials: C
authors.lastname: Jackisch
authors.forename: Manuel
authors.initials: M
authors.lastname: Constenla
authors.forename: Joseph N
authors.initials: JN
authors.lastname: Kerger
authors.forename: Robert
authors.initials: R
authors.lastname: Paridaens
authors.forename: Leo
authors.initials: L
authors.lastname: Auerbach
authors.forename: André
authors.initials: A
authors.lastname: Bosly
authors.forename: Ruth
authors.initials: R
authors.lastname: Pettengell
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Szucs
authors.forename: Robert
authors.initials: R
authors.lastname: Leonard
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D018943:Anthracyclines / Q000008:administration & dosage / Q000009:adverse effects; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000009:adverse effects* / Q000145:classification; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008485:Medical Audit; D008875:Middle Aged; D009367:Neoplasm Staging; D009503:Neutropenia / Q000139:chemically induced* / Q000453:epidemiology; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D018943:Anthracyclines; D000970:Antineoplastic Agents