title: Incidence of pain flare following palliative radiotherapy for symptomatic bone metastases: multicenter prospective observational study.
abstract: BACKGROUND
  Palliative radiotherapy (RT) is an effective treatment for symptomatic bone metastases. Pain flare, a transient worsening of the bone pain after RT, has been described in previous reports with different incidence rates. The aim of the study was to prospectively evaluate the incidence of pain flare following RT for painful bone metastases and evaluate its effects on pain control and functionality of the patients.
  
  
  METHODS
  Between June 2010 and June 2014, 204 patients were enrolled in this study and 135 patients with complete data were evaluable. Pain flare was defined as a 2- point increase in worst pain score as compared with baseline with no decrease in analgesic intake or a 25% increase in analgesic intake as compared with baseline with no decrease in worst pain score. All pain medications and worst pain scores were collected before, daily during, and for 10 days after RT. The Brief Pain Inventory (BPI) was filled out on the pretreatment and at the 4 weeks follow-up visit.
  
  
  RESULTS
  There were 90 men (66.7%) and 45 women (33.3%). Mean age was 66 years (SD 9.8). The most common primary cancer site was lung in 42 patients (31.1%), followed by prostate in 27 patients (20.0%). Forty-two patients (31.1%) patients received a single fraction of 8 Gy and 83 (61.5%) received 20 Gy in five fractions. The overall pain flare incidence across all centers was 51/135 (37.7%). The majority of pain flares occurred on days 1-5 (88.2%). The mean duration of the pain flare was 3 days (SD: 3). There were no significant relationships between the occurrence of pain flare and collected variables. All BPI items measured four weeks after end of RT showed significant improvement as compared with pretreatment scores (p < 0.001). No significant differences in BPI time trends were found between patients with and without flare pain.
  
  
  CONCLUSIONS
  Pain flare is a common event, occurring in nearly 40% of the patients that receive palliative RT for symptomatic bone metastases. This phenomenon is not a predictor for pain response.
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Cruces/ Biocruces Health Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain. agomeziturriaga@gmail.com.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Gomez-Iturriaga
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Cruces/ Biocruces Health Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain. JON.CACICEDOFERNANDEZBOBADILLA@osakidetza.net.
authors.forename: Jon
authors.initials: J
authors.lastname: Cacicedo
authors.affiliation: Department of Radiation Oncology, Instituto Catalan de Oncología, Avinguda de la Gran via de l'Hospitalet, 199-203, 08907 L'Hospitalet de Llobregat, Barcelona, Spain. anavarro@iconcologia.net.
authors.forename: Arturo
authors.initials: A
authors.lastname: Navarro
authors.affiliation: Department of Radiation Oncology, Hospital de Castellón, Carrer de les Useres, 1, 12006, Castelló de la Plana, Castelló, Spain. vmorill@hotmail.com.
authors.forename: Virginia
authors.initials: V
authors.lastname: Morillo
authors.affiliation: Department of Radiation Oncology, Hospital Meixoeiro, Meixoeiro, s/n, 36200 Vigo, Pontevedra, Spain. patriciawillisch@hotmail.com.
authors.forename: Patricia
authors.initials: P
authors.lastname: Willisch
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Cruces/ Biocruces Health Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain.
authors.forename: Claudia
authors.initials: C
authors.lastname: Carvajal
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Cruces/ Biocruces Health Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Hortelano
authors.affiliation: Department of Radiation Oncology, Hospital Virgen Del Rocío, Av Manuel Siurot, s/n, 41013, Sevilla, Spain. chanodetriana@yahoo.es.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Lopez-Guerra
authors.affiliation: Department of Radiation Oncology, Hospital Virgen Macarena, Avd. Dr Fedriani, 3, 41071, Sevilla, Spain. aillesc@hotmail.com.
authors.forename: Ana
authors.initials: A
authors.lastname: Illescas
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Cruces/ Biocruces Health Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Casquero
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Cruces/ Biocruces Health Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Del Hoyo
authors.affiliation: Department of Radiation Oncology, Hospital San Chinarro, C/ Oña, 10, 28050, Madrid, Spain. raquel.ciervide@gmail.com.
authors.forename: Raquel
authors.initials: R
authors.lastname: Ciervide
authors.affiliation: Clinical Epidemiology Unit, Hospital Universitario Cruces/ Biocruces Heatlh Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain. ANA.IRASARRISEBASTIAN@osakidetza.eus.
authors.forename: Ana
authors.initials: A
authors.lastname: Irasarri
authors.affiliation: Clinical Epidemiology Unit, Hospital Universitario Cruces/ Biocruces Heatlh Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain. JOSEIGNACIO.PIJOANZUBIZARRET@osakidetza.eus.
authors.forename: Jose Ignacio
authors.initials: JI
authors.lastname: Pijoan
authors.affiliation: Department of Radiation Oncology, Hospital Universitario Cruces/ Biocruces Health Research Institute, Plaza Cruces 12, 48903, Barakaldo, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Bilbao
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000150:complications* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000532:radiotherapy*; D010146:Pain / Q000532:radiotherapy*; D010166:Palliative Care; D011446:Prospective Studies; D011878:Radiotherapy / Q000009:adverse effects* / Q000379:methods