Trends in stage-specific breast cancer incidence in New South Wales, Australia: insights into the effects of 25 years of screening mammography
- 648 Downloads
Screening mammography aims to improve breast cancer (BC) prognosis by increasing the incidence of early-stage tumours in order to decrease the incidence of late-stage cancer, but no reports have investigated these potential effects in an Australian population. Therefore we aimed to identify temporal trends in stage-specific BC in New South Wales (NSW), Australia, between 1972 and 2012.
An observational study of women who received a diagnosis of BC from 1972–2012 as recorded in the NSW Cancer Registry, a population-based registry with almost complete coverage and high rates of histological verification. We analysed trends in stage-specific incidence before screening and compared them to periods after screening began. Our primary group of interest was women in the target age range of 50–69 years, though trends in women outside the target age were also assessed.
Screening was not associated with lower incidence of late-stage BC at diagnosis. Incidence for all stages remained higher than prescreening levels. In women aged 50–69 years, the incidence of carcinoma in situ (CIS), localised and regional BC has more than doubled compared to the prescreening era, with incidence rate ratios ranging from 2.0 for regional (95% CI 1.95–2.13) to 121.8 for CIS (95% CI 82.58–179.72). Before the introduction of screening, there was a downward trend in distant metastatic BC incidence, and after the introduction of screening there was an increase (IRR 1.8; 95% CI 1.62–2.00). In women too young to screen the incidence of late-stage BC at diagnosis also increased, whereas localised disease was stable.
The incidence of all stages of BC has increased over the past 40 years, with the greatest rise seen during the established screening period for women aged 50–69 years. Our findings suggest that some of the expected benefits of screening may not have been realised and are consistent with overdiagnosis.
KeywordsBreast neoplasms Mass screening Mammography Epidemiology Medical overuse
Carcinoma in situ
Hormone replacement therapy
Incidence rate ratios
Incidence rate differences
Medicare benefits schedule
New South Wales
New South Wales Cancer Registry
Sentinel node biopsy
This work was supported by grants from the National Health and Medical Research Centre, Australia. A postgraduate scholarship (Grant No 1074626) was awarded to GJ and a Centre for Research Excellence award (Grant No 1104136) was awarded to AB. Incidence data were supplied by the NSW Central Cancer Registry, which is managed and operated by The Cancer Council NSW under contract to the NSW Health Department.
Compliance with ethical standards
Conflicts of interest
All authors declare that they do not have any conflicts of interest to report.
Our research protocol was approved by the research ethics board of the NSW Population & Health Services Research Ethics Committee (Cancer Institute NSW reference number: LNR 2014/07/032).
- 2.Morrison AS (1992) Screening in chronic disease. Monographs in epidemiology and biostatistics (Book 19), 2nd edn. Oxford University Press, New YorkGoogle Scholar
- 13.Australian Institute of Health and Welfare (2017) Australian Cancer Incidence and Mortality (ACIM) books: Breast cancer. Available from: AIHW. www.aihw.gov.au/acim-books. Accessed 7 June 2017
- 14.Osborn M, Armstrong B, Kricker A, Coates M (1999) Current recording and registration practices for carcinoma in situ (CIS) of the breast in Australasian State and Territory cancer registries. NHMRC National Breast Cancer Centre, SydneyGoogle Scholar
- 15.Australian Bureau of Statistics (2014) Australian Historical Population Statistics, 2014. Population Age-Sex Structure. Available from: http://www.abs.gov.au/ausstats/abs@.nsf/0/632CDC28637CF57ECA256F1F0080EBCC?Opendocument. Accessed 9 Feb 2017
- 16.Young JL Jr, Roffers SD, Ries LAG, Fritz AG, Hurlbut AA (eds) (2001) SEER summary staging manual—2000: codes and coding instructions. National Cancer Institute, BethesdaGoogle Scholar
- 17.Department of Health and Ageing (2009) BreastScreen Australia evaluation. Screening Monograph No.1/2009. Evaluation final report. Canberra, AustraliaGoogle Scholar
- 18.Cancer Institute NSW (2006) Annual report 2005–2006. Cancer Institute NSW, SydneyGoogle Scholar
- 19.Australian Bureau of Statistics (2013) Which population to use for age standardisation? Australian Bureau of Statistics. Available from: http://www.abs.gov.au/ausstats/abs@.nsf/products/42479A8EF04E40EBCA257C430016EA3B?OpenDocument. Accessed 31 May 2017
- 20.SAS Institute Inc (2011) SAS version 9.4 of the SAS System for Windows. SAS Institute Inc, CaryGoogle Scholar
- 21.Esteve J, Benhamou E, Raymond L (1994) Statistical methods in cancer research. Volume IV. Descriptive epidemiology. IARC Sci Publ 1(128):302Google Scholar
- 28.Chlebowski RT, Hendrix SL, Langer RD, Stefanick ML, Gass M, Lane D, Rodabough RJ, Gilligan MA, Cyr MG, Thomson CA (2003) Influence of estrogen plus progestin on breast cancer and mammography in healthy postmenopausal women: the Women’s Health Initiative Randomized Trial. JAMA 289(24):3243–3253CrossRefPubMedGoogle Scholar
- 31.Australian Bureau of Statistics (1996) 1995 National Nutrition Survey. Basic Confidentialised Unit Record File (CURF), CD-ROM. Findings based on use of ABS Microdata. Canberra, AustraliaGoogle Scholar
- 32.Australian Bureau of Statistics (2002) 2001 National Health Survey. Expanded Confidentialised Unit Record File (CURF), Remote Access Data Laboratory (RADL). Findings based on use of ABS Microdata. Canberra, AustraliaGoogle Scholar
- 38.Bilous M, Morey A, Armes J, Cummings M, Francis G (2006) Chromogenic in situ hybridisation testing for HER2 gene amplification in breast cancer produces highly reproducible results concordant with fluorescence in situ hybridisation and immunohistochemistry. Pathology (Phila) 38(2):120–124Google Scholar
- 42.Hunter DJ, Spiegelman D, Adami H-O, van den Brandt PA, Folsom AR, Goldbohm RA, Graham S, Howe GR, Kushi LH, Marshall JR, Miller AB, Speizer FE, Willett W, Wolk A, Yaun S-S (1997) Non-dietary factors as risk factors for breast cancer, and as effect modifiers of the association of fat intake and risk of breast cancer. Cancer Causes Control 8(1):49–56CrossRefPubMedGoogle Scholar
- 45.Autier P (2016) Mammography screening effectiveness and overdiagnosis in the Netherlands. In: Paper presented at the 4th international conference on Preventing Overdiagnosis, Barcelona, Spain, 20–22 SeptGoogle Scholar
- 48.de Glas NA, de Craen AJ, Bastiaannet E, Op’t Land EG, Kiderlen M, van de Water W, Siesling S, Portielje JE, Schuttevaer HM, de Bock GTH (2014) Effect of implementation of the mass breast cancer screening programme in older women in the Netherlands: population based study. BMJ 349:g5410CrossRefPubMedPubMedCentralGoogle Scholar
- 50.Karssemeijer N, Bluekens AM, Beijerinck D, Deurenberg JJ, Beekman M, Visser R, Rv Engen, Bartels-Kortland A, Broeders MJ (2009) Breast cancer screening results 5 years after introduction of digital mammography in a population-based screening program. Radiology 253(2):353–358CrossRefPubMedGoogle Scholar
- 52.Cancer Institute NSW (2016) Annual NSW cancer incidence and mortality data set, 2012. Cancer Registry NSW. Available at: http://www.statistics.cancerinstitute.org.au/trends_agegroup/trends_agegroup_mort_C50_NSW_extall_2.htm. Accessed 1 Aug 2017
- 59.Fisher B, Anderson S, Bryant J, Margolese RG, Deutsch M, Fisher ER, Jeong J-H, Wolmark N (2002) Twenty-year follow-up of a randomized trial comparing total mastectomy, lumpectomy, and lumpectomy plus irradiation for the treatment of invasive breast cancer. N Engl J Med 347(16):1233–1241CrossRefPubMedGoogle Scholar
- 60.Identifier NCT02926911, Comparison of operative to monitoring and endocrine therapy (COMET) trial for low risk DCIS (COMET), 2016 Sept 19 (2000) National Library of Medicine (US). Available at: https://clinicaltrials.gov/ct2/show/NCT02926911. Accessed 4 June 2017