BMC Cancer
Volume 18, Issue 1, 2018

Ethnic disparities in breast cancer survival in New Zealand: Which factors contribute? (Article) (Open Access)

Tin Tin S.* , Elwood J.M. , Brown C. , Sarfati D. , Campbell I. , Scott N. , Ramsaroop R. , Seneviratne S. , Harvey V. , Lawrenson R.
  • a The University of Auckland, Section of Epidemiology and Biostatistics, School of Population Health, Auckland, New Zealand
  • b The University of Auckland, Section of Epidemiology and Biostatistics, School of Population Health, Auckland, New Zealand
  • c SMART Marketing and Research, Hamilton, New Zealand
  • d The University of Otago, Department of Public Health, Wellington, New Zealand
  • e The University of Auckland, Waikato Clinical Campus, Hamilton, New Zealand, Waikato District Health Board, Hamilton, New Zealand
  • f Waikato District Health Board, Hamilton, New Zealand
  • g Waitemata District Health Board, Surgical Pathology Department, Auckland, New Zealand
  • h The University of Colombo, Department of Surgery, Colombo, Sri Lanka
  • i Auckland District Health Board, Auckland, New Zealand
  • j National Institute of Demographic and Economic Analysis, The University of Waikato, Hamilton, New Zealand, Waikato District Health Board, Hamilton, New Zealand

Abstract

Background: New Zealand has major ethnic disparities in breast cancer survival with Maori (indigenous people) and Pacific women (immigrants or descended from immigrants from Pacific Islands) faring much worse than other ethnic groups. This paper identified underlying factors and assessed their relative contribution to this risk differential. Methods: This study involved all women who were diagnosed with primary invasive breast cancer in two health regions, covering about 40% of the national population, between January 2000 and June 2014. Maori and Pacific patients were compared with other ethnic groups in terms of demographics, mode of diagnosis, disease factors and treatment factors. Cox regression modelling was performed with stepwise adjustments, and hazards of excess mortality from breast cancer for Maori and Pacific patients were assessed. Results: Of the 13,657 patients who were included in this analysis, 1281 (9.4%) were Maori, and 897 (6.6%) were Pacific women. Compared to other ethnic groups, they were younger, more likely to reside in deprived neighbourhoods and to have co-morbidities, and less likely to be diagnosed through screening and with early stage cancer, to be treated in a private care facility, to receive timely cancer treatment, and to receive breast conserving surgery. They had a higher risk of excess mortality from breast cancer (age and year of diagnosis adjusted hazard ratio: 1.76; 95% CI: 1.51-2.04 for Maori and 1.97; 95% CI: 1.67-2.32 for Pacific women), of which 75% and 99% respectively were explained by baseline differences. The most important contributor was late stage at diagnosis. Other contributors included neighbourhood deprivation, mode of diagnosis, type of health care facility where primary cancer treatment was undertaken and type of loco-regional therapy. Conclusions: Late diagnosis, deprivation and differential access to and quality of cancer care services were the key contributors to ethnic disparities in breast cancer survival in New Zealand. Our findings underscore the need for a greater equity focus along the breast cancer care pathway, with an emphasis on improving access to early diagnosis for Maori and Pacific women. © 2018 The Author(s).

Author Keywords

Breast cancer Ethnic groups mediation Survival New Zealand

Index Keywords

genetics breast cancer proportional hazards model Proportional Hazards Models demography human delayed diagnosis comorbidity middle aged population group cancer survival Ethnic Groups Population Groups ethnic group pathology Aged cancer staging cancer screening social status Breast Neoplasms ethnic difference Humans early intervention cancer survivor Maori (people) urban rural difference breast tumor female Socioeconomic Factors cancer radiotherapy risk factor Risk Factors Pacific islands socioeconomics Cancer Survivors Pacific Islander mastectomy antineoplastic agent partial mastectomy cancer therapy Article major clinical study adult health care quality health care access New Zealand age diagnostic procedure patient attitude Patient Acceptance of Health Care health care facility mortality risk
Link
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040372944&doi=10.1186%2fs12885-017-3797-0&partnerID=40&md5=63a05e6054125c973b34ac1ff42567b5
DOI: 10.1186/s12885-017-3797-0
ISSN: 14712407
Cited by: 6
Original Language: English