title: Risk of second cancers cancer after a first primary breast cancer: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To examine the scientific evidence and the risk of second primary cancers in women diagnosed with a first primary breast cancer.
  
  
  METHODS
  The literature was searched in Pubmed and Embase and included studies published up to June 2013, using population-based data and IARC/AICR codification rules for multiple primary cancers. A qualitative synthesis was carried out and the methodological quality of the studies evaluated. Standardised incidence ratios (SIRs) on second cancer risk, weighted by the standard error of each study, were pooled using fixed and random effects models. SIRs were also pooled by age at diagnosis (<50 and ≥ 50 years), and time since diagnosis of the first breast cancer (<10 and ≥ 10 years).
  
  
  RESULTS
  15 out of 710 articles fulfilled the inclusion criteria. All of them were retrospective cohort studies either population-based (13 studies) or hospital-based studies (2 studies). The studies varied with respect to number of cases, selection criteria, definition of multiple primary cancers, and the second cancer sites included. SIRs reported in these studies for all cancers combined varied from 1.0 to 1.4. The pooled SIR estimate for second cancer risk was 1.17 (95% CI: 1.10-1.25). By age groups, SIR estimates were 1.51 (95% CI: 1.35-1.70) for women younger than 50 years and 1.11 (95% CI: 1.02-1.21) for those who were older. Women with breast cancer are at risk of second cancers within the first 10 years after the first breast cancer diagnosis (SIR: 1.19; 95% CI: 1.06-1.33), and thereafter (SIR: 1.26; 95% CI: 1.05-1.52).
  
  
  CONCLUSIONS
  This higher risk of second cancers in women diagnosed with a first primary breast cancer with respect to the general population emphasises the importance of prevention and control policies aimed at reducing incidence of second cancers.
authors.affiliation: Granada Cancer Registry, Andalusian School of Public Health, Granada Spain; Instituto de Investigación Biosanitaria de Granada (Granada.ibs), Hospitales Universitarios de Granada/Universidad de Granada, Granada, Spain; CIBER de Epidemiología y Salud Pública (CIBERESP), Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Molina-Montes
authors.affiliation: Granada Cancer Registry, Andalusian School of Public Health, Granada Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Requena
authors.affiliation: Granada Cancer Registry, Andalusian School of Public Health, Granada Spain; Instituto de Investigación Biosanitaria de Granada (Granada.ibs), Hospitales Universitarios de Granada/Universidad de Granada, Granada, Spain; CIBER de Epidemiología y Salud Pública (CIBERESP), Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Sánchez-Cantalejo
authors.affiliation: Instituto de Investigación Biosanitaria de Granada (Granada.ibs), Hospitales Universitarios de Granada/Universidad de Granada, Granada, Spain; CIBER de Epidemiología y Salud Pública (CIBERESP), Spain; Radiology Department, University of Granada, Granada, Spain.
authors.forename: Mariana F
authors.initials: MF
authors.lastname: Fernández
authors.affiliation: Instituto de Investigación Biosanitaria de Granada (Granada.ibs), Hospitales Universitarios de Granada/Universidad de Granada, Granada, Spain; Physical Therapy Department, University of Granada, Granada, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Arroyo-Morales
authors.affiliation: Granada Cancer Registry, Andalusian School of Public Health, Granada Spain; Instituto de Investigación Biosanitaria de Granada (Granada.ibs), Hospitales Universitarios de Granada/Universidad de Granada, Granada, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: Espín
authors.affiliation: Instituto de Investigación Biosanitaria de Granada (Granada.ibs), Hospitales Universitarios de Granada/Universidad de Granada, Granada, Spain; CIBER de Epidemiología y Salud Pública (CIBERESP), Spain; Radiology Department, University of Granada, Granada, Spain.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Arrebola
authors.affiliation: Granada Cancer Registry, Andalusian School of Public Health, Granada Spain; Instituto de Investigación Biosanitaria de Granada (Granada.ibs), Hospitales Universitarios de Granada/Universidad de Granada, Granada, Spain; CIBER de Epidemiología y Salud Pública (CIBERESP), Spain. Electronic address: mariajose.sanchez.easp@juntadeandalucia.es.
authors.forename: María-José
authors.initials: MJ
authors.lastname: Sánchez
mesh_terms: D001943:Breast Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016609:Neoplasms, Second Primary / Q000453:epidemiology*; D012306:Risk
keywords: Breast neoplasms; Meta-analysis; Multiple primary; Risk; Second primary; Systematic review