title: Survival of older patients with metastasised breast cancer lags behind despite evolving treatment strategies--a population-based study.
abstract: BACKGROUND
  Older women are more likely to be diagnosed with primary metastasised breast cancer than their younger counterparts. Evolving treatment strategies of metastasised breast cancer have resulted in improved survival in younger patients, but it remains unclear if this improvement has occurred in older patients as well. The aim of this study was to assess changes in treatment strategies over time in relation to overall and relative survival of older patients compared to younger patients with primary metastasised breast cancer.
  
  
  METHODS
  All patients with a breast cancer diagnosis and distant metastases at first presentation (stage IV), between 1990 and 2012, were selected from the Netherlands Cancer Registry. Changes in treatment over time per age-group (<65 years, 65-75 years and >75 years) were assessed using logistic regression. Overall survival over time was calculated using Cox Regression Models and relative survival was assessed using the Ederer II method.
  
  
  RESULTS
  Overall, 14,310 patients were included. Treatment strategies have strongly changed in the past twenty years; especially the use of chemotherapy has increased (P<0.001 in all age-groups). Overall survival of patients <65 has significantly improved (Hazard Ratio (HR) per year 0.98, 95% Confidence Interval (CI) 0.98-0.99, P<0.001), but the survival of older patients has not improved (HR 1.00, 95% CI 0.99-1.01, P=0.86 for patients aged 65-75 and HR 1.00, 95% CI 1.00-1.01, P=0.46 for patients aged >75). Similarly, relative survival has improved in patients <65 but not in women aged 65-75 and >75.
  
  
  CONCLUSIONS
  Overall and relative survival of older patients with metastasised breast cancer at first presentation have not improved in recent years in contrast with the survival of younger patients, despite increased treatment with chemotherapy for women of all ages. Future studies should focus on stratification models that can be used to predict which patients may benefit from specific treatment options.
authors.affiliation: Leiden University Medical Center, Department of Surgery, P.O. Box 9600, 2300 RC Leiden, The Netherlands; Leiden University Medical Center, Department of Gerontology & Geriatrics, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: N A
authors.initials: NA
authors.lastname: de Glas
authors.affiliation: Leiden University Medical Center, Department of Surgery, P.O. Box 9600, 2300 RC Leiden, The Netherlands; Leiden University Medical Center, Department of Gerontology & Geriatrics, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Bastiaannet
authors.affiliation: Leiden University Medical Center, Department of Gerontology & Geriatrics, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: A J M
authors.initials: AJ
authors.lastname: de Craen
authors.affiliation: Leiden University Medical Center, Department of Surgery, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
authors.affiliation: Comprehensive Cancer Centre the Netherlands, Department of Research, P.O. Box 19079, 3501 DB Utrecht, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Siesling
authors.affiliation: Leiden University Medical Center, Department of Surgery, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: G J
authors.initials: GJ
authors.lastname: Liefers
authors.affiliation: Haga Hospital The Hague, Department of Internal Medicine, Leyweg 275, 2545 CH Den Haag, The Netherlands. Electronic address: j.portielje@hagaziekenhuis.nl.
authors.forename: J E A
authors.initials: JE
authors.lastname: Portielje
mesh_terms: D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D024221:Antineoplastic Protocols; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D003131:Combined Modality Therapy / Q000639:trends*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009426:Netherlands / Q000453:epidemiology; D012042:Registries; D016019:Survival Analysis
keywords: Breast cancer; Geriatric oncology; Metastasised breast cancer; Older patients; Treatment