title: High Body Mass Index and Young Age Are not Associated with Post-Mastectomy Pain Syndrome in Breast Cancer Survivors: A Case-Control Study.
abstract: BACKGROUND
  Surgery is usually the first treatment for breast cancer which is followed by some complications such as chronic pain. Post mastectomy pain syndrome (PMPS) is a common complication among breast cancer survivors and is considered as a chronic neuropathic pain in the side of surgery which persists more than three months. The exact mechanisms and related risk factors of the chronic pain after breast surgery are unknown. The aim of this study was to investigate the association of body mass index (BMI) and age with PMPS.
  
  
  METHODS
  In this case-control study, a total of 122 women were assessed; of these, 61 women were diagnosed with PMPS and selected as cases and 61 pain-free patients were selected as controls. The demographic and clinical characteristics of participants were collected through questionnaires and medical record of patients. Logistic regression model was used to determine the association of BMI and age with PMPS, adjusted for demographic and clinical characteristics.
  
  
  RESULTS
  No significant differences were found in means of weight (68.02±8.80 vs. 68.67±11.82, p=0.726), BMI (26.38±3.28 vs. 27.10±6.03, p=0.410), and age (46.34±11.67 vs. 48.54±12.57, p=0.319) between those with PMPS and those not reporting PMPS. A non-significant slight increase in odds ratio of PMPS was observed in obese category compared to normal weight category [OR=1.152 (95% CI 0.405-3.275), p=0.908], but after adjusting the confounding factors, the risk of pain development was attenuated in obese subjects [OR=0.748 (95% CI 0.228-2.459), p=0.633]. Also, non-significant decrease in odds ratios of PMPS was found in 20-39 y, 40-49 y, and 50-59 y ages categories compared to oldest age category [adjusted OR= 0.781 (95% CI 0.213-2.866), p=0.576; adjusted OR=0.485 (95% CI 0.152- 1.554), p=0.183; adjusted OR=0.735 (95% CI 0.206-2.627), p=0.628; respectively].
  
  
  CONCLUSIONS
  In contrast with some observational studies, present study showed that high BMI and younger age might not be associated with increased risk of PMPS development. Further research is necessary to determine the main risk factors and directionality and causal mechanisms for associations of these risk factors with chronic pain after mastectomy.
authors.affiliation: National Institute and Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Roghayeh
authors.initials: R
authors.lastname: Shahbazi
authors.affiliation: Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Esmaeil
authors.initials: ME
authors.lastname: Akbari
authors.affiliation: Dept. of Anesthesiology and Pain Medicine, Bahonar Hospital, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Morteza
authors.initials: M
authors.lastname: Hashemian
authors.affiliation: National Institute and Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mehrnaz
authors.initials: M
authors.lastname: Abbasi
authors.affiliation: National Institute and Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Saba
authors.initials: S
authors.lastname: Jalali
authors.affiliation: Dept. of Biochemistry, Fasa University of Medical Sciences, Fasa, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Homayounfar
authors.affiliation: Dept. of Clinical Nutrition and Dietetic, National Institute and Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Sayed Hossein
authors.initials: SH
authors.lastname: Davoodi
keywords: Age; BMI; Breast cancer; Post-mastectomy pain syndrome; Risk factors
references.citation: Obesity (Silver Spring). 2012 Jul;20(7):1491-5
references.pmid: 22262163
references.citation: Pain. 1999 Oct;83(1):91-5
references.pmid: 10506676
references.citation: Pain. 2003 Jul;104(1-2):265-73
references.pmid: 12855337
references.citation: Breast J. 2010 Jan-Feb;16(1):48-54
references.pmid: 19889169
references.citation: Br J Cancer. 2007 May 7;96(9):1462-8
references.pmid: 17406360
references.citation: Breast Cancer Res Treat. 2013 Jan;137(2):617-30
references.pmid: 23242613
references.citation: Int J Fertil Womens Med. 2006 Mar-Apr;51(2):75-82
references.pmid: 16881383
references.citation: Br J Cancer. 2008 Aug 19;99(4):604-10
references.pmid: 18682712
references.citation: Rev Bras Anestesiol. 2009 May-Jun;59(3):358-65
references.pmid: 19488550
references.citation: Arch Surg. 2010 Mar;145(3):224-5
references.pmid: 20231621
references.citation: Pain. 2005 Dec 15;119(1-3):16-25
references.pmid: 16298063
references.citation: Br J Cancer. 2005 Jan 31;92(2):225-30
references.pmid: 15655557
references.citation: Int J Obes Relat Metab Disord. 2004 Feb;28(2):269-77
references.pmid: 14610533
references.citation: Pain Med. 2009 May-Jun;10(4):708-15
references.pmid: 19453965
references.citation: Health Psychol. 2004 Jul;23(4):381-7
references.pmid: 15264974
references.citation: Pain Manag Nurs. 2009 Dec;10(4):197-205
references.pmid: 19944375
references.citation: BMJ. 2013 Apr 11;346:f1865
references.pmid: 23580693
references.citation: J Pain. 2006 Sep;7(9):626-34
references.pmid: 16942948
references.citation: Int J Radiat Oncol Biol Phys. 2012 May 1;83(1):71-8
references.pmid: 22079722
references.citation: Breast. 2012 Jun;21(3):321-5
references.pmid: 22377590
references.citation: JAMA. 2009 Nov 11;302(18):1985-92
references.pmid: 19903919
references.citation: J Pain Symptom Manage. 2007 Oct;34(4):380-92
references.pmid: 17583467
references.citation: ScientificWorldJournal. 2013 Nov 27;2013:159732
references.pmid: 24379736
references.citation: Br J Surg. 2001 Aug;88(8):1122-6
references.pmid: 11488800
references.citation: J Pain. 2012 Jan;13(1):64-72
references.pmid: 22208802