Stage of breast cancer at diagnosis in New Zealand: impacts of socio-demographic factors, breast cancer screening and biology.

Sanjeewa Seneviratne,Ross Lawrenson,Ian Campbell,Vernon Harvey,Diana Sarfati,Mark Elwood,Reena Ramsaroop,Nina Scott

doi:10.1186/s12885-016-2177-5

Abstract

BackgroundExamination of factors associated with late stage diagnosis of breast cancer is useful to identify areas which are amenable to intervention. This study analyses trends in cancer stage at diagnosis and impact of socio-demographic, cancer biological and screening characteristics on cancer stage in a population-based series of women with invasive breast cancer in New Zealand.MethodsAll women diagnosed with invasive breast cancer between 2000 and 2013 were identified from two regional breast cancer registries. Factors associated with advanced (stages III and IV) and metastatic (stage IV) cancer at diagnosis were analysed in univariate and multivariate models adjusting for covariates.ResultsOf the 12390 women included in this study 2448 (19.7 %) were advanced and 575 (4.6 %) were metastatic at diagnosis. Māori (OR = 1.86, 1.39-2.49) and Pacific (OR = 2.81, 2.03-3.87) compared with NZ European ethnicity, other urban (OR = 2.00, 1.37-2.92) compared with main urban residency and non-screen (OR = 6.03, 4.41-8.24) compared with screen detection were significantly associated with metastatic cancer at diagnosis in multivariate analysis. A steady increase in the rate of metastatic cancer was seen which has increased from 3.8 % during 2000-2003 to 5.0 % during 2010-2013 period (p = 0.042).ConclusionsProviding equitable high quality primary care and increasing mammographic screening coverage needs to be looked at as possible avenues to reduce late-stage cancer at diagnosis and to reduce ethnic, socioeconomic and geographical disparities in stage of breast cancer at diagnosis in New Zealand.

Highlights

Examination of factors associated with late stage diagnosis of breast cancer is useful to identify areas which are amenable to intervention
Data from the two registries were linked with the New Zealand Cancer Registry (NZCR) and the National Mortality Collection (NMC)
human epidermal growth factor type-2 (HER-2) status was not available for 23.2 % of the women, a majority (84.2 %) of whom were diagnosed with breast cancer prior to 2006

Summary

Introduction

Examination of factors associated with late stage diagnosis of breast cancer is useful to identify areas which are amenable to intervention. The diagnostic pathway is important – population based screening with mammography has been shown to increase the proportion of women diagnosed with early breast cancer [4]. In New Zealand, late diagnosis with advanced or metastatic disease has been associated with Māori ethnicity and social deprivation [5]. Differences by ethnicity and social deprivation have important associations in other countries [6,7,8,9], while in some countries it has been shown that women living outside main urban areas are more likely to be diagnosed with advanced disease [10]

Methods

Results

Conclusion