title: High mammographic breast density predicts locoregional recurrence after modified radical mastectomy for invasive breast cancer: a case-control study.
abstract: We aimed to evaluate the influence of mammographic breast density at diagnosis on the risk of cancer recurrence and survival outcomes in patients with invasive breast cancer after modified radical mastectomy.
  
  
  
  This case-control study included 121 case-control pairs of women diagnosed with invasive breast cancer between 2004 and 2009, and who had undergone modified radical mastectomy and had mammographic breast density measured before or at diagnosis. Women with known locoregional recurrence or distant metastasis were matched by pathological disease stage, age, and year of diagnosis to women without recurrence. Locoregional recurrence was defined as recurrence in the ipsilateral chest wall, or axillary, internal mammary, or supraclavicular nodes. The median follow-up duration was 84.0 months for case patients and 92.9 months for control patients.
  
  
  
  Patients with heterogeneously dense (50-75% density) and extremely dense (>75% density) breasts had an increased risk of locoregional recurrence (hazard ratios 3.1 and 5.7, 95% confidence intervals 1.1-9.8 and 1.2-34.9, p = 0.043 and 0.048, respectively) than did women with less dense breasts. Positive margins after surgery also increased the risk of locoregional recurrence (hazard ratio 3.3, 95% confidence interval 1.3-8.3, p = 0.010). Multivariate analysis that included dense breasts (>50% density), positive margin, no adjuvant radiotherapy, and no adjuvant chemotherapy revealed that dense breasts were significant factors for predicting locoregional recurrence risk (hazard ratio 3.6, 95% confidence interval 1.2-11.1, p = 0.025).
  
  
  
  Our results demonstrate that dense breast tissue (>50% density) increased the risk of locoregional recurrence after modified radical mastectomy in patients with invasive breast cancer. Additional prospective studies are necessary to validate these findings.
  
  
  
  The study is retrospectively registered with ClinicalTrials.gov, number NCT02771665 , on May 11, 2016.
authors.affiliation: Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei, Taiwan.|Department of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, No. 7, Chung-Shan S. Rd., Taipei, 100, Taiwan.|Department of Medical Imaging, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan.
authors.forename: Yu-Sen
authors.initials: YS
authors.lastname: Huang
authors.affiliation: Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei, Taiwan.|Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.|Department of Radiation Oncology, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan.
authors.forename: Jenny Ling-Yu
authors.initials: JL
authors.lastname: Chen
authors.affiliation: Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Chiun-Sheng
authors.initials: CS
authors.lastname: Huang
authors.affiliation: Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Sung-Hsin
authors.initials: SH
authors.lastname: Kuo
authors.affiliation: Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Fu-Shan
authors.initials: FS
authors.lastname: Jaw
authors.affiliation: Department of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, No. 7, Chung-Shan S. Rd., Taipei, 100, Taiwan.
authors.forename: Yao-Hui
authors.initials: YH
authors.lastname: Tseng
authors.affiliation: Department of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, No. 7, Chung-Shan S. Rd., Taipei, 100, Taiwan.
authors.forename: Wei-Chun
authors.initials: WC
authors.lastname: Ko
authors.affiliation: Department of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, No. 7, Chung-Shan S. Rd., Taipei, 100, Taiwan. ycc5566@ntu.edu.tw.
authors.forename: Yeun-Chung
authors.initials: YC
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000071060:Breast Density; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008327:Mammography; D015411:Mastectomy, Modified Radical; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000517:prevention & control; D011379:Prognosis; D016016:Proportional Hazards Models
keywords: Breast cancer; Case-control study; Distant metastasis; Loco-regional recurrence; Mammographic breast density; Modified radical mastectomy