Hamilton, New Zealand
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Seneviratne S.,University of Auckland | Campbell I.,University of Auckland | Scott N.,Maori Health Services | Kuper-Hommel M.,Waikato District Health Board | And 3 more authors.
Breast | Year: 2015

Purpose: Despite the benefits of adjuvant endocrine therapy for hormone receptor positive breast cancer, many women are non-adherent or discontinue endocrine treatment early. We studied differences in adherence to adjuvant endocrine therapy by ethnicity in a cohort of New Zealand women with breast cancer and its impact on breast cancer outcomes. Methods: We analysed data on women (n=1149) with newly diagnosed hormone receptor positive, non-metastatic, invasive breast cancer who were treated with adjuvant endocrine therapy in the Waikato during 2005-2011. Linked data from the Waikato Breast Cancer Registry and National Pharmaceutical Database were examined to identify differences by ethnicity in adherence to adjuvant endocrine therapy and the effect of sub-optimal adherence on cancer recurrence and mortality. Results: Overall, a high level of adherence of ≥80% was observed among 70.4% of women, which declined from 76.8% to 59.3% from the first to fifth year of treatment. Māori women were significantly more likely to be sub-optimally adherent (<80%) compared with European women (crude rate 37% vs. 28%, p=0.005, adjusted OR = 1.51, 95% CI 1.04-2.17). Sub-optimal adherence was associated with a significantly higher risk of breast cancer mortality (HR=1.77, 95% CI 1.05-2.99) and recurrence (HR=2.14, 95% CI 1.46-3.14). Conclusions: Sub-optimal adherence to adjuvant endocrine therapy was a likely contributor for breast cancer mortality inequity between Māori and European women, and highlights the need for future research to identify effective ways to increase adherence in Māori women. © 2014 Elsevier Ltd.


PubMed | University of Auckland, Maori Health Services, Waikato Hospital and Waikato District Health Board
Type: Journal Article | Journal: Breast (Edinburgh, Scotland) | Year: 2015

Despite the benefits of adjuvant endocrine therapy for hormone receptor positive breast cancer, many women are non-adherent or discontinue endocrine treatment early. We studied differences in adherence to adjuvant endocrine therapy by ethnicity in a cohort of New Zealand women with breast cancer and its impact on breast cancer outcomes.We analysed data on women (n=1149) with newly diagnosed hormone receptor positive, non-metastatic, invasive breast cancer who were treated with adjuvant endocrine therapy in the Waikato during 2005-2011. Linked data from the Waikato Breast Cancer Registry and National Pharmaceutical Database were examined to identify differences by ethnicity in adherence to adjuvant endocrine therapy and the effect of sub-optimal adherence on cancer recurrence and mortality.Overall, a high level of adherence of 80% was observed among 70.4% of women, which declined from 76.8% to 59.3% from the first to fifth year of treatment. Mori women were significantly more likely to be sub-optimally adherent (<80%) compared with European women (crude rate 37% vs. 28%, p=0.005, adjusted OR = 1.51, 95% CI 1.04-2.17). Sub-optimal adherence was associated with a significantly higher risk of breast cancer mortality (HR=1.77, 95% CI 1.05-2.99) and recurrence (HR=2.14, 95% CI 1.46-3.14).Sub-optimal adherence to adjuvant endocrine therapy was a likely contributor for breast cancer mortality inequity between Mori and European women, and highlights the need for future research to identify effective ways to increase adherence in Mori women.


Seneviratne S.,University of Auckland | Campbell I.,University of Auckland | Scott N.,Maori Health Services | Shirley R.,Waikato Hospital | And 2 more authors.
Cancer Epidemiology | Year: 2014

Purpose: Population based cancer registries are an invaluable resource for monitoring incidence and mortality for many types of cancer. Research and healthcare decisions based on cancer registry data rely on the case completeness and accuracy of recorded data. This study was aimed at assessing completeness and accuracy of breast cancer staging data in the New Zealand Cancer Registry (NZCR) against a regional breast cancer register. Methodology: Data from 2562 women diagnosed with invasive primary breast cancer between 1999 and 2011 included in the Waikato Breast Cancer Register (WBCR) were used to audit data held on the same individuals by the NZCR. WBCR data were treated as the benchmark. Results: Of 2562 cancers, 315(12.3%) were unstaged in the NZCR. For cancers with a known stage in the NZCR, staging accuracy was 94.4%. Lower staging accuracies of 74% and 84% were noted for metastatic and locally invasive (involving skin or chest wall) cancers, respectively, compared with localized (97%) and lymph node positive (94%) cancers. Older age (>80 years), not undergoing therapeutic surgery and higher comorbidity score were significantly (. p<. 0.01) associated with unstaged cancer. The high proportion of unstaged cancer in the NZCR was noted to have led to an underestimation of the true incidence of metastatic breast cancer by 21%. Underestimation of metastatic cancer was greater for Māori (29.5%) than for NZ European (20.6%) women. Overall 5-year survival rate for unstaged cancer (NZCR) was 55.9%, which was worse than the 5-year survival rate for regional (77.3%), but better than metastatic (12.9%) disease. Conclusions: Unstaged cancer and accuracy of cancer staging in the NZCR are major sources of bias for the NZCR based research. Improving completeness and accuracy of staging data and increasing the rate of TNM cancer stage recording are identified as priorities for strengthening the usefulness of the NZCR. © 2014 Elsevier Ltd.


Seneviratne S.,University of Auckland | Seneviratne S.,Waikato Hospital | Campbell I.,University of Auckland | Scott N.,Maori Health Services | And 3 more authors.
Cancer Causes and Control | Year: 2015

Purpose: We investigated the breast cancer survival disparity between Indigenous Māori and non-Indigenous European women in New Zealand, and quantified the relative contributions of patient, tumor and healthcare system factors toward this disparity. Methods: All women diagnosed with breast cancer in Waikato, New Zealand, during 1999–2012 were identified from the Waikato Breast Cancer Register. Cancer-specific survivals were compared using Kaplan–Meier survival curves, while contributions of different factors toward the survival disparity were quantified with serial Cox proportional hazard modeling. Results: Of the 2,679 women included in this study, 2,260 (84.4 %) were NZ European and 419 (15.6 %) were Māori. Compared with NZ European women, Māori women had a significantly higher age-adjusted cancer-specific mortality (HR 2.02, 95 % CI 1.59–2.58) with significantly lower 5-year (86.8 vs. 76.1 %, p < 0.001) and 10-year (79.9 vs. 66.9 %, p < 0.001 %) crude cancer-specific survivals. Stage at diagnosis made the greatest contribution (approximately 25–40 %), while screening, treatment and patient factors (i.e., comorbidity, obesity and smoking) contributed by approximately 15 % each toward the survival disparity. The final model accounted for almost all of the cancer survival disparity (HR 1.07, 95 % CI 0.80–1.44). Conclusions: Māori women experience an age-adjusted risk of death from breast cancer, which is more than twice that for NZ European women. Equity-focussed improvements in health care, including increasing mammographic screening coverage and providing equitable quality and timely cancer care, may improve the survival disparity between Māori and NZ European women. © 2015, Springer International Publishing Switzerland.


Seneviratne S.,University of Auckland | Seneviratne S.,University of Colombo | Seneviratne S.,Waikato Hospital | Campbell I.,University of Auckland | And 3 more authors.
BMC Public Health | Year: 2015

Background: Indigenous Ma¯ori women experience a 60% higher breast cancer mortality rate compared with European women in New Zealand. We explored the impact of differences in rates of screen detected breast cancer on inequities in cancer stage at diagnosis and survival between Ma¯ori and NZ European women. Methods: All primary breast cancers diagnosed in screening age women (as defined by the New Zealand National Breast Cancer Screening Programme) during 1999-2012 in the Waikato area (n∈=∈1846) were identified from the Waikato Breast Cancer Register and the National Screening Database. Stage at diagnosis and survival were compared for screen detected (n∈=∈1106) and non-screen detected (n∈=∈740) breast cancer by ethnicity and socioeconomic status. Results: Indigenous Ma¯ori women were significantly more likely to be diagnosed with more advanced cancer compared with NZ European women (OR∈=∈1.51), and approximately a half of this difference was explained by lower rate of screen detected cancer for Ma¯ori women. For non-screen detected cancer, Ma¯ori had significantly lower 10-year breast cancer survival compared with NZ European (46.5% vs. 73.2%) as did most deprived compared with most affluent socioeconomic quintiles (64.8% vs. 81.1%). No significant survival differences were observed for screen detected cancer by ethnicity or socioeconomic deprivation. Conclusions: The lower rate of screen detected breast cancer appears to be a key contributor towards the higher rate of advanced cancer at diagnosis and lower breast cancer survival for Ma¯ori compared with NZ European women. Among women with screen-detected breast cancer, Ma¯ori women do just as well as NZ European women, demonstrating the success of breast screening for Ma¯ori women who are able to access screening. Increasing breast cancer screening rates has the potential to improve survival for Ma¯ori women and reduce breast cancer survival inequity between Ma¯ori and NZ European women. © 2015 Seneviratne et al.; licensee BioMed Central.


PubMed | University of Auckland, Maori Health Services and Waikato Breast Cancer Trust
Type: Journal Article | Journal: Cancer causes & control : CCC | Year: 2015

We investigated the breast cancer survival disparity between Indigenous Mori and non-Indigenous European women in New Zealand, and quantified the relative contributions of patient, tumor and healthcare system factors toward this disparity.All women diagnosed with breast cancer in Waikato, New Zealand, during 1999-2012 were identified from the Waikato Breast Cancer Register. Cancer-specific survivals were compared using Kaplan-Meier survival curves, while contributions of different factors toward the survival disparity were quantified with serial Cox proportional hazard modeling.Of the 2,679 women included in this study, 2,260 (84.4%) were NZ European and 419 (15.6%) were Mori. Compared with NZ European women, Mori women had a significantly higher age-adjusted cancer-specific mortality (HR 2.02, 95% CI 1.59-2.58) with significantly lower 5-year (86.8 vs. 76.1%, p < 0.001) and 10-year (79.9 vs. 66.9%, p < 0.001%) crude cancer-specific survivals. Stage at diagnosis made the greatest contribution (approximately 25-40%), while screening, treatment and patient factors (i.e., comorbidity, obesity and smoking) contributed by approximately 15% each toward the survival disparity. The final model accounted for almost all of the cancer survival disparity (HR 1.07, 95% CI 0.80-1.44).Mori women experience an age-adjusted risk of death from breast cancer, which is more than twice that for NZ European women. Equity-focussed improvements in health care, including increasing mammographic screening coverage and providing equitable quality and timely cancer care, may improve the survival disparity between Mori and NZ European women.


PubMed | University of Auckland, Maori Health Services and Waikato Hospital
Type: Journal Article | Journal: Public health | Year: 2015

The aim of this study is to identify key characteristics associated with mortality from breast cancer among women with newly diagnosed breast cancer in New Zealand (NZ).Case-control study.All primary breast cancers diagnosed between 01/01/2002 and 31/12/2010 in Waikato, NZ, were identified from the Waikato Breast Cancer Register. A total of 258 breast cancer deaths were identified from 1767 invasive cancers diagnosed over this period.Breast cancer deaths (n=246) were compared with an age and year of diagnosis matched control group (n=652) who were alive at the time of the death of the corresponding case and subsequently did not die from breast cancer. Diagnosis through symptomatic presentation, advanced stage, higher grade, absent hormone receptors (i.e. oestrogen and progesterone) and HER-2 amplification were associated with significantly higher risks of breast cancer mortality in bivariate analysis. Tumour stage, grade and hormone receptor status remained significant in the multivariable model, while mode of detection and HER-2 status were non-significant. In the bivariate analysis, Mori women had a higher risk of breast cancer mortality compared to NZ European women (OR 1.34) which was statistically non-significant. However in the adjusted model, risk of mortality was lower for Mori compared to NZ European women, although this was not significant statistically (OR 0.85).Mortality pattern from breast cancer in this study were associated with established risk factors. Ethnic inequity in breast cancer mortality in NZ appears to be largely attributable to delay in diagnosis and tumour related factors. Further research in a larger cohort is needed to identify the full impact of these factors on ethnic inequity in breast cancer mortality.


PubMed | University of Auckland, Maori Health Services, University of Otago and Auckland District Health Board
Type: | Journal: BMC cancer | Year: 2016

Examination 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.All 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.Of the 12390 women included in this study 2448 (19.7%) were advanced and 575 (4.6%) were metastatic at diagnosis. Mori (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).Providing 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.


PubMed | University of Auckland, Maori Health Services and Waikato Hospital
Type: Journal Article | Journal: PloS one | Year: 2015

Indigenous Mori women have a 60% higher breast cancer mortality rate compared with European women in New Zealand. We investigated differences in cancer biological characteristics and their impact on breast cancer mortality disparity between Mori and NZ European women.Data on 2849 women with primary invasive breast cancers diagnosed between 1999 and 2012 were extracted from the Waikato Breast Cancer Register. Differences in distribution of cancer biological characteristics between Mori and NZ European women were explored adjusting for age and socioeconomic deprivation in logistic regression models. Impacts of socioeconomic deprivation, stage and cancer biological characteristics on breast cancer mortality disparity between Mori and NZ European women were explored in Cox regression models.Compared with NZ European women (n=2304), Mori women (n=429) had significantly higher rates of advanced and higher grade cancers. Mori women also had non-significantly higher rates of ER/PR negative and HER-2 positive breast cancers. Higher odds of advanced stage and higher grade remained significant for Mori after adjusting for age and deprivation. Mori women had almost a 100% higher age and deprivation adjusted breast cancer mortality hazard compared with NZ European women (HR=1.98, 1.55-2.54). Advanced stage and lower proportion of screen detected cancer in Mori explained a greater portion of the excess breast cancer mortality (HR reduction from 1.98 to 1.38), while the additional contribution through biological differences were minimal (HR reduction from 1.38 to 1.35).More advanced cancer stage at diagnosis has the greatest impact while differences in biological characteristics appear to be a minor contributor for inequities in breast cancer mortality between Mori and NZ European women. Strategies aimed at reducing breast cancer mortality in Mori should focus on earlier diagnosis, which will likely have a greater impact on reducing breast cancer mortality inequity between Mori and NZ European women.


PubMed | University of Auckland and Maori Health Services
Type: | Journal: ANZ journal of surgery | Year: 2015

Indigenous Mori are known to experience inferior quality cancer care compared with non-Indigenous Europeans in New Zealand. However, limited data are available on ethnic/socio-economic differences in surgical treatment of breast cancer, or reasons for such variations within the local context. We investigated ethnic/socio-economic differences in rates of mastectomy, sentinel node biopsy (SNB), post-mastectomy breast reconstruction and definitive local therapy for breast cancer in New Zealand.A retrospective review of prospective data in the Waikato Breast Cancer Register for women diagnosed during 1999-2012 was performed. Differences in rates of mastectomy (for stage I/II, T1/T2 cancers), SNB (for stage I/II, T1/T2, cN0 cancers), post-mastectomy breast reconstruction (for non-metastatic cancers in women <70 years) and definitive local therapy (for stage I/II cancers) were analysed in univariate and multivariate regression models, adjusting for covariates.Significantly lower mastectomy and higher reconstruction rates were associated with younger age, private compared with public hospital care and screen compared with non-screen detection. Compared with NZ Europeans, Mori (41% versus 33%, P = 0.025) were significantly more likely to undergo mastectomy for cancers, which were potentially amenable for breast conserving surgery, but were significantly less likely to undergo post-mastectomy breast reconstruction (12% versus 35%, P < 0.001). No significant ethnic or socio-economic differences were observed in rates of SNB or definitive local therapy.This study has demonstrated lower rates of breast conserving surgery and reconstructions in Mori compared with NZ European women, and highlight the need for future research to focus on understanding the reasons behind these findings.

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