title: Mammographic density: a potential monitoring biomarker for adjuvant and preventative breast cancer endocrine therapies.
abstract: Increased mammographic density (MD) has been shown beyond doubt to be a marker for increased breast cancer risk, though the underpinning pathobiology is yet to be fully elucidated. Estrogenic activity exerts a strong influence over MD, which consequently has been observed to change predictably in response to tamoxifen anti-estrogen therapy, although results for other selective estrogen receptor modulators and aromatase inhibitors are less consistent. In both primary and secondary prevention settings, tamoxifen-associated MD changes correlate with successful modulation of risk or outcome, particularly among pre-menopausal women; an observation that supports the potential use of MD change as a surrogate marker where short-term MD changes reflect longer-term anti-estrogen efficacy. Here we summarize endocrine therapy-induced MD changes and attendant outcomes and discuss both the need for outcome surrogates in such therapy, as well as make a case for MD as such a monitoring marker. We then discuss the process and steps required to validate and introduce MD into practice as a predictor or surrogate for endocrine therapy efficacy in preventive and adjuvant breast cancer treatment settings.
authors.affiliation: Department of Head and Neck and Endocrine Surgery, Faculty of Medicine, University of Alexandria, Egypt.|Department of Surgery, University College Hospital, London, UK.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Shawky
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, and Department of Medical Oncology, Fiona Stanley Hospital, Perth, Western Australia, Australia.
authors.forename: Hilary
authors.initials: H
authors.lastname: Martin
authors.affiliation: Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology, Australia.|Translational Research Institute, Brisbane, Australia.
authors.forename: Honor J
authors.initials: HJ
authors.lastname: Hugo
authors.affiliation: Department of Radiology, Princess Alexandra Hospital, Brisbane, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lloyd
authors.affiliation: The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia.|Peter MacCallum Cancer Centre, Melbourne, Australia.|Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.
authors.forename: Kara L
authors.initials: KL
authors.lastname: Britt
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, and Department of Medical Oncology, Fiona Stanley Hospital, Perth, Western Australia, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Redfern
authors.affiliation: Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology, Australia.|Translational Research Institute, Brisbane, Australia.|Department of Surgery, University of Melbourne, St Vincent's Hospital, Melbourne, Australia.
authors.forename: Erik W
authors.initials: EW
authors.lastname: Thompson
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D000071060:Breast Density / Q000187:drug effects*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology*; D005260:Female; D006801:Humans; D008327:Mammography; D013629:Tamoxifen / Q000627:therapeutic use
chemical_list: D018931:Antineoplastic Agents, Hormonal; D013629:Tamoxifen
keywords: breast cancer; endocrine therapy; mammographic density; predictive biomarker; surrogate