REPCAN: Guideline for REporting Population-based CANcer Registry Data.

Background: The objective of this study was to develop a guideline on how to report result of a population-based cancer registry. Methods: The guideline's development involved a core working committee and a scientific committee comprising experts from diverse domains. The process comprised three steps: 1) a comprehensive review of existing tools and guidelines and the development of the initial draft of the guideline based on a review of literature, 2) refinement items through several rounds of focus group discussion among the core group, and development initial draft, and 3) Evaluation of the initial draft by scientific committee members. Items in the guideline were organized to accommodate reports of population-based cancer registries as a scientific manuscript. Results: The core committee developed 47 items distributed in the major heading of a scientific manuscript presented as a checklist. The evaluation of the scientific committee led to a consensus on the majority of the items included in the checklist. Among 10 committee members, 7 provided unreserved approval, validating each item's necessity, applicability, and comprehensibility in the checklist. Feedback from the remaining 3 members was carefully analyzed and integrated to enhance the guideline's robustness. Incorporating feedback, a first final draft was presented in a meeting of scientific and core working committee members. Collaborative discussion ensured clarity of expression for each items and a final checklist was developed. Conclusion: The guideline abbreviated as REPCAN offers a standardized framework for reporting population-based cancer registry, fostering transparency, comparability, and comprehensive data presentation. The guideline encourages flexibility while promoting comprehensive and robust reporting practices.

Increased Early Cancer Diagnosis: Unveiling Immune-Cancer Biology to Explain Clinical "Overdiagnosis".

Even though clinically small 'early' cancers represent many millions of cells biologically, when removed surgically, these often never recur or regrow, nor reduce the individual's lifespan. However, some early cancers remain quiescent and indolent; while others grow and metastasize, threatening life. Distinguishing between these different clinical behaviours using clinical/pathological criteria is currently problematic. It is reported that many suspicious lesions and early cancers are being removed surgically that would not threaten the patient's life. This has been termed 'overdiagnosis', especially in the sphere of cancer screening. Although a controversial and emotive topic, it poses clinical and public health policy challenges. The diagnostic differentiation between 'non-lethal' and 'lethal' tumor forms is generally impossible. One perspective gathering evidential support is that a dynamic balance exists between the immune response and malignant processes governing 'lethality', where many more cancers are produced than become clinically significant due to the immune system preventing their progression. Higher medical screening "diagnosis" rates may reflect lead-time effects, with more 'non-progressing' cancers detected when an early immune-cancer interaction is occurring. We present a model for this immune-cancer interaction and review 'excess' or 'overdiagnosis' claims that accompany increasingly sensitive diagnostic and screening technologies. We consider that immune tools should be incorporated into future research, with potential for immune system modulation for some early cancers.

Second Primary Cancers Following Cancer Among Adolescents and Young Adults in Queensland, Australia, 1982-2018.

Purpose: Increased risk of second primary cancers is an unwanted consequence of cancer survivorship. While the epidemiology of second cancers is well-documented for children and older people, less is known about second cancers among adolescent and young adult (AYA) cancer survivors. Methods: Unit record data were obtained from the Queensland Cancer Register. The study cohort comprised Queensland residents aged 15 to 39 years who were diagnosed with a first primary invasive cancer between 1982 and 2013. Follow-up on second cancers was available for a minimum of 5 years to the end of 2018. Standardized incidence ratios (SIRs) were used to approximate the risk of a second primary cancer relative to the general population. Results: In total, 3086 second primary cancers were observed among 34,431 eligible AYA patients (9%), equating to an overall SIR of 1.59 (95% confidence interval [CI] 1.53-1.64). Melanoma (n = 853, 28%) and female breast cancer (n = 594, 19%) were the most common types of second primary cancer in the study cohort. Relative risk of all second primary cancers combined among AYA patients was inversely associated with age and was highest within the period immediately after first diagnosis irrespective of age group; for example, patients aged 15-24 at first diagnosis recorded more than four times as many second primary cancers than expected within 2 years of their first cancer (SIR = 4.40, 95% CI 2.83-6.82). Conclusions: Detailed data on second primary cancers among AYA cancer survivors are important in promoting increased awareness and to inform the development of targeted prevention and surveillance strategies.

Colorectal cancer and country of birth in New South Wales, Australia: All-of-population data for prioritising health service delivery and research.

INTRODUCTION: Cancer care and outcomes differ across cultural groups in Australia. Quantifying these differences facilitates prioritisation and targeting of services and research. All-of-population data are needed by health agencies to understand and fulfil their cancer-control responsibilities. Compiling these data can be challenging while maintaining privacy. We have used data linkage to gain population-wide colorectal cancer data on stage (degree of spread), treatment, and survival in New South Wales (NSW), Australia, by country of birth (COB), and consider service implications. METHODS: We studied colon and rectal cancers diagnosed in 2003-2016 and recorded on the NSW Cancer Registry (n = 41,575), plus linked hospital data and data from Australian Medical and Pharmaceutical Benefits payments, other treatment data and death records. Outcomes for 12 COB categories were analysed using multiple logistic and proportional hazards regression, with Australia as the reference category. RESULTS: Compared with Australian born, the adjusted odds ratio for distant spread of colon cancer was higher for people born in Lebanon and the United Kingdom. Treatment was less common for people born in China (surgery), Germany (systemic), Italy (surgery), New Zealand (any treatment) and Vietnam (all treatments), while treatment for rectal cancer was more common for people born in Italy (surgery), United Kingdom (radiotherapy, systemic therapy), and Vietnam (surgery), and less frequent for people born in China (radiotherapy). Adjusted 5-year survival was higher for people born in China, Italy, Vietnam, Greece (colon), Lebanon (colon) and other non-English speaking countries. More advanced stage was negatively related to having surgery and survival. CONCLUSIONS: This study illustrates how linked data can enable comparisons of multiple outcomes for colorectal cancer by country of birth across an entire population. Results disclose "big picture" variations in population characteristics, stage, treatment and survival. This will enable better targeting and prioritisation of services and inform research priorities to address disparities.

Changes in five-year survival for people with acute leukaemia in South Australia, 1980-2016.

OBJECTIVES: To examine population changes in 5-year survival for people in South Australia diagnosed with acute leukaemia during 1980-2016, by socio-demographic characteristics. DESIGN, SETTING: Retrospective analysis of South Australian Cancer Registry data for the period 1980-2016. PARTICIPANTS: All South Australian residents diagnosed with primary acute lymphoblastic leukaemia (ALL) or acute myeloid leukaemia (AML) during 1980-2016. MAIN OUTCOME MEASURES: 5-year disease-specific survival and disease-specific mortality. RESULTS: Crude 5-year disease-specific survival was 58% (95% CI, 54-61%) for the 1035 people diagnosed with ALL during 1980-2016, and 18% (95% CI, 17-20%) for the 2814 people diagnosed with AML. Survival improved steadily across the study period: from 44% (95% CI, 35-52%) for people with ALL diagnosed during 1980-1984 to 69% (95% CI, 63-75%) for those diagnosed during 2010-2016; and from 9% (95% CI, 5-15%) to 23% (95% CI, 20-26%) for people diagnosed with AML. Disease-specific mortality increased with age, but was not influenced by socio-economic status or remoteness of residence. After adjusting for other factors, rates of change in risk of leukaemia-related death were greater for younger than older patients with ALL (for interaction: P = 0.004) or AML (P = 0.005), but were not significantly influenced by socio-economic status or remoteness. CONCLUSION: Five-year survival for people with acute leukaemia in South Australia continuously improved during 1980-2016, and socio-economic status and remoteness did not influence survival. It improved markedly for younger patients (under 50 years of age). However, survival is still relatively poor, especially for people over 50 years with AML.

Investigating the breast cancer screening-treatment-mortality pathway of women diagnosed with invasive breast cancer: Results from linked health data.

OBJECTIVE: To examine the screening-treatment-mortality pathway among women with invasive breast cancer in 2006-2014 using linked data. METHODS: BreastScreen histories of South Australian women diagnosed with breast cancer (n = 8453) were investigated. Treatments recorded within 12 months from diagnosis were obtained from linked registry and administrative data. Associations of screening history with treatment were investigated using logistic regression and with cancer mortality outcomes using competing risk analyses, adjusting for socio-demographic, cancer and comorbidity characteristics. RESULTS AND CONCLUSION: For screening ages of 50-69 years, 70% had participated in BreastScreen SA ≤ 5 years and 53% ≤ 2 years of diagnosis. Five-year disease-specific survival post-diagnosis was 90%. Compared with those not screened ≤5 years, women screened ≤2 years had higher odds, adjusted for socio-demographic, cancer and comorbidity characteristics, and diagnostic period, of breast-conserving surgery (aOR 2.5, 95% CI 1.9-3.2) and radiotherapy (aOR 1.2, 95% CI 1.1-1.3). These women had a lower unadjusted risk of post-diagnostic cancer mortality (SHR 0.33, 95% CI 0.27-0.41), partly mediated by stage (aSHR 0.65, 95% CI 0.51-0.81), and less breast surgery (aSHR 0.78, 95% CI 0.62-0.99). Screening ≤2 years and conserving surgery appeared to have a greater than additive association with lower post-diagnostic mortality (interaction term SHR 0.42, 95% CI 0.23-0.78). The screening-treatment-mortality pathway was investigated using linked data.

Late mortality in people with cancer: a population-based Australian study.

OBJECTIVES: To investigate causes of death of people with cancer alive five years after diagnosis, and to compare mortality rates for this group with those of the general population. DESIGN, SETTING, PARTICIPANTS: Retrospective cohort study; analysis of South Australian Cancer Registry data for all people diagnosed with cancer during 1990-1999 and alive five years after diagnosis, with follow-up to 31 December 2016. MAIN OUTCOME MEASURES: All-cause and cancer cause-specific mortality, by cancer diagnosis; standardised mortality ratios (study group v SA general population) by sex, age at diagnosis, follow-up period, and index cancer. RESULTS: Of 32 646 people with cancer alive five years after diagnosis, 30 309 were of European background (93%) and 16 400 were males (50%); the mean age at diagnosis was 60.3 years (SD, 15.7 years). The median follow-up time was 17 years (IQR, 11-21 years); 17 268 deaths were recorded (53% of patients; mean age, 80.6 years; SD, 11.4 years): 7845 attributed to cancer (45% of deaths) and 9423 attributed to non-cancer causes (55%). Ischaemic heart disease was the leading cause of death (2393 deaths), followed by prostate cancer (1424), cerebrovascular disease (1175), and breast cancer (1118). The overall standardised mortality ratio (adjusted for age, sex, and year of diagnosis) was 1.24 (95% CI, 1.22-1.25). The cumulative number of cardiovascular deaths exceeded that of cancer cause-specific deaths from 13 years after cancer diagnosis. CONCLUSIONS: Mortality among people with cancer who are alive at least five years after diagnosis was higher than for the general population, particularly cardiovascular disease-related mortality. Survivorship care should include early recognition and management of risk factors for cardiovascular disease.

Breast Cancer Incidence and Survival Among Young Females in Queensland, Australia.

Purpose: Breast cancer is the most common cancer diagnosed among adolescent and young adult (AYA) females worldwide, but epidemiological patterns unique to this group are often obscured when results are combined with older patients. This study investigates breast cancer incidence and survival among AYA females, including differences by broad stage at diagnosis. Methods: A retrospective, population-based cohort study was conducted using de-identified data for females in Queensland, Australia, aged 15-39 diagnosed with a first primary breast cancer between 1997 and 2014 with follow-up to December 31, 2016. Incidence rate trends were examined with Joinpoint analysis. Cause-specific survival was calculated for key characteristics, and 5-year adjusted hazard ratios (HRs) were estimated from a multivariable flexible parametric model. Results: The study cohort comprised 2337 patients, of whom two-thirds (n = 1565, 67%) were diagnosed with advanced disease (tumor diameter >20 mm, lymph node involvement or presence of distant metastases at diagnosis). Incidence rates of localized tumors decreased by 1.9% per year (95% confidence interval [CI] -3.5% to -0.4%) over the study period, whereas the trend for advanced breast cancers remained stable. Five-year cause-specific survival increased from 85% to 92% for 2011-2014 compared to 1997-2001 (adjusted HR = 0.43, 95% CI = 0.29-0.65). Patients who were Indigenous from disadvantaged areas or diagnosed with advanced stage experienced significantly worse survival. Conclusion: The high proportion of younger females diagnosed with advanced breast cancer should be the focus of future campaigns to improve awareness and earlier detection. While survival has increased over time, further work is required to ensure that this progress is experienced equitably by all patients.

Keratinocyte cancers in South Australia: incidence, geographical variability and service trends.

OBJECTIVES: To determine the incidence, multiplicity, geographical variability and service trends of keratinocyte cancers (KC) in South Australia (SA). METHODS: Medicare Australia data with a unique identifier were used to assess the number of people treated over years 2010-2014. A maximum of one KC service claim per year was used to determine incidence. Age-standardised rates were estimated as were KC service activity trends. RESULTS: There were 497,581 services to 204,183 SA residents for KC, solar keratoses, locally aggressive skin tumours or suspicious skin lesions. Of these, n=159,137 services were for KC (77,502 people). The five-year (2010-2014) age-standardised rate of KC in SA was 1,466.6 (95%CI 1,458.3-1,474.8) per 100,000. Forty per cent of people had more than one KC removed. Men accounted for more incident cases (59.2%). Age-specific rates showed least variability over time in the youngest age group (15-44 years). For 26 geographical areas, higher age-standardised ratios of KC were seen in coastal and agricultural areas. There was a 59% increase in services for KC from 2000 to 2015. CONCLUSIONS: Age-standardised rates for KC are relatively stable in SA, but regional variations are evident. Services for KC continue to rise. Implications for public health: This is the first systematic report of KC in SA. We demonstrate the utility of using validated Medicare data for assessing KC incidence and trends.

Comorbidities in Australian women with hormone-dependent breast cancer: a population-based analysis.

OBJECTIVE: To compare how frequently selected chronic diseases developed in women with breast cancer receiving endocrine therapy, and in women without cancer. DESIGN, SETTING AND PARTICIPANTS: Retrospective, rolling cohort study, analysing a random 10% sample of Pharmaceutical Benefits Scheme (PBS) data for the period 1 January 2003 - 31 December 2014. Women with breast cancer who first commenced endocrine therapy between January 2004 and December 2011 were identified, and age- and sex-matched (1:10) by comorbidity with control groups of women who did not have a dispensing record for antineoplastic agents during the study period or the comorbidity of interest at baseline. MAIN OUTCOME MEASURES: Development of any of eight pre-selected comorbidities, identified in PBS claims data with the RxRisk-V model. RESULTS: Women with hormone-dependent breast cancer were significantly more likely than women in the control group to develop depression (overall hazard ratio [HR], 1.36; 95% CI, 1.26-1.46), pain or pain-inflammation (HR, 1.30; 95% CI, 1.23-1.38), osteoporosis (overall HR, 1.27; 95% CI, 1.17-1.39), diabetes (HR, 1.24; 95% CI, 1.10-1.41), cardiovascular disorders (overall HR, 1.22; 95% CI, 1.13-1.32), and gastric acid disorders (HR, 1.20; 95% CI, 1.13-1.28). The hazard ratios for developing cardiovascular disorders, depression and osteoporosis were highest during the first year of endocrine therapy. The risk of hyperlipidaemia was lower among women with breast cancer than in the control group (HR, 0.88; 95% CI, 0.81-0.96). There was no significant difference between the two groups in the risk of reactive airway diseases (HR, 1.05; 95% CI, 0.98-1.13). CONCLUSION: Comorbid conditions are more likely to develop in women who have been diagnosed with hormone-dependent breast cancer than in women without cancer. Our results further support the need to develop appropriate models of care to manage the multiple chronic disorders of breast cancer survivors.

Australian Adolescents and Young Adults-Trends in Cancer Incidence, Mortality, and Survival Over Three Decades.

PURPOSE: Cancer is a significant health concern for adolescents and young adults (AYAs; aged 15-24 years). Monitoring population-level changes in incidence, mortality, and survival is complicated by the lack of published data presenting statistics separately for AYAs. This study synthesizes and reviews data on AYA cancers in Australia, including trends in incidence and mortality. METHODS: National data were extracted for 1980-2012, primarily from the Australian Cancer Database and Australian National Mortality Database. Incidence, mortality, and survival trends are described, and incidence and mortality projections are reported. RESULTS: In 2000-2009, the annual all-cancer incidence was 31.7 cases per 100,000 population, and the mortality rate was 4.1 per 100,000. Incidence, mortality, and survival varied widely, indicating areas of concern. Melanoma was the most common cancer, and bone cancer had the highest mortality and poorest survival rates. All-cancer incidence rates peaked in the late 1990s, but then declined, largely due to melanoma. All-cancer mortality decreased throughout the study period, but showed no improvements for some common sites (i.e., brain, bone, soft tissue). Further reductions in all-cancer incidence and mortality are projected for the next decade, although specific cancers (colorectal cancers and lymphomas) were projected to increase in incidence. CONCLUSIONS: Observed Australian cancer trends are largely consistent with trends for other high-income populations. While overall decreases in incidence and mortality are encouraging, consistently high mortality and poor survival for some cancers remain concerning. Planned data initiatives for AYAs with cancer will aid in resolving whether trends continue and projections are realized in the future.

Time to clinical investigation for Indigenous and non-Indigenous Queensland women after a high grade abnormal Pap smear, 2000-2009.

OBJECTIVES: To investigate time to follow-up (clinical investigation) for Indigenous and non-Indigenous women in Queensland after a high grade abnormality (HGA) being detected by Pap smear. DESIGN, SETTING, PARTICIPANTS: Population-based retrospective cohort analysis of linked data from the Queensland Pap Smear Register (PSR), the Queensland Hospital Admitted Patient Data Collection, and the Queensland Cancer Registry. 34 980 women aged 20-68 years (including 1592 Indigenous women) with their first HGA Pap smear result recorded on the PSR (index smear) during 2000-2009 were included and followed to the end of 2010. MAIN OUTCOME MEASURES: Time from the index smear to clinical investigation (histology test or cancer diagnosis date), censored at 12 months. RESULTS: The proportion of women who had a clinical investigation within 2 months of a HGA finding was lower for Indigenous (34.1%; 95% CI, 31.8-36.4%) than for non-Indigenous women (46.5%; 95% CI, 46.0-47.0%; unadjusted incidence rate ratio [IRR], 0.65; 95% CI, 0.60-0.71). This difference remained after adjusting for place of residence, area-level disadvantage, and age group (adjusted IRR, 0.74; 95% CI, 0.68-0.81). However, Indigenous women who had not been followed up within 2 months were subsequently more likely to have a clinical investigation than non-Indigenous women (adjusted IRR for 2-4 month interval, 1.21; 95% CI, 1.08-1.36); by 6 months, a similar proportion of Indigenous (62.2%; 95% CI, 59.8-64.6%) and non-Indigenous women (62.8%; 95% CI, 62.2-63.3%) had been followed up. CONCLUSIONS: Prompt follow-up after a HGA Pap smear finding needs to improve for Indigenous women. Nevertheless, slow follow-up is a smaller contributor to their higher cervical cancer incidence and mortality than their lower participation in cervical screening.

Pancreatectomy is underused in NSW regions with low institutional surgical volumes: a population data linkage study.

OBJECTIVE: To examine differences in the proportions of people diagnosed with pancreatic cancer who underwent pancreatectomy, post-operative outcomes and 5-year survival in different New South Wales administrative health regions of residence. DESIGN, SETTING AND PARTICIPANTS: Retrospective analysis of NSW data on pancreatic cancer incidence and surgery, 2005-2013. MAIN OUTCOME MEASURES: The proportion of newly diagnosed patients with pancreatic cancer who were resected in each region; 90-day post-operative mortality; one-year post-operative survival; 5-year post-diagnosis survival. RESULTS: 14% of people diagnosed with pancreatic cancer during 2010-2013 (431 of 3064) underwent pancreatectomy, an average of 108 resections per year. After adjusting for age, sex and comorbidities, the proportion that underwent resection varied significantly between regions, ranging between 8% and 21% (P<0.001). Higher resection rates were not associated with higher post-operative 90-day mortality or lower one-year survival (unadjusted and risk-adjusted analyses). Higher resection rates were associated with higher 5-year post-diagnosis survival: the mean survival in regions with resection rates below 10% was 3.4%, compared with 7.2% in regions with rates greater than 15% (unadjusted and adjusted survival analyses; P<0.001). There was a positive association between regional resection rate and the pancreatectomy volume of hospitals during 2005-2009. An additional 32 people would be resected annually if resection rates in low rate regions were increased to the 80th percentile regional resection rate (18%). CONCLUSION: There is significant geographic variation in the proportion of people with pancreatic cancer undergoing pancreatectomy, and the 5-year survival rate is higher in regions where this proportion is higher.

Prostate cancer outcomes for men who present with symptoms at diagnosis.

OBJECTIVE: To compare clinical features, treatments and outcomes in men with non-metastatic prostate cancer (PCa) according to whether they were referred for symptoms or elevated prostate-specific antigen (PSA) level. PATIENTS AND METHODS: This study used data from the South Australia Prostate Cancer Clinical Outcomes Collaborative database; a multi-institutional clinical registry covering both the public and private sectors. We included all non-metastatic cases from 1998 to 2013 referred for urinary/prostatic symptoms or elevated PSA level. Multivariate Poisson regression was used to identify characteristics associated with symptomatic presentation and compare treatments according to reason for referral. Outcomes (i.e. overall survival, PCa-specific survival, metastasis-free survival and disease-free survival) were compared using multivariate Cox proportional hazards and competing risk regression. RESULTS: Our analytical cohort consisted of 4 841 men with localized PCa. Symptomatic men had lower-risk disease (incidence ratio [IR] 0.70, 95% confidence interval [CI] 0.61-0.81 for high vs low risk), fewer radical prostatectomies (IR 0.64, CI: 0.56-0.75) and less radiotherapy (IR 0.86, CI: 0.77-0.96) than men presenting with elevated PSA level. All-cause mortality (hazard ratio [HR] 1.31, CI: 1.16-1.47), disease-specific mortality (HR 1.42, CI: 1.13-1.77) and risk of metastases (HR 1.36, CI: 1.13-1.64) were higher for men presenting with symptoms, after adjustment for other clinical characteristics; however, risk of disease progression did not differ (HR 0.90, CI: 0.74-1.07) amongst those treated curatively. Subgroup analyses indicated poorer PCa survival for symptomatic referral among men undergoing radical prostatectomy (HR 3.4, CI: 1.3-8.8), those aged >70 years (HR 1.4, CI: 1.0-1.8), men receiving private treatment (HR 2.1, CI: 1.3-3.3), those diagnosed via biopsy (HR 1.3, CI: 1.0-1.7) and those diagnosed before 2006 (HR 1.6, CI: 1.2-2.7). CONCLUSION: Our results suggest that symptomatic presentation may be an independent negative prognostic indicator for PCa survival. More complete assessment of disease grade and extent, more definitive treatment and increased post-treatment monitoring among symptomatic cases may improve outcomes. Further research to determine any pathophysiological basis for poor outcomes in symptomatic men is warranted.

The utility of linked cancer registry and health administration data for describing system-wide outcomes and research: a BreastScreen example.

RATIONALE, AIMS AND OBJECTIVES: Stratification of women with screen-detected ductal carcinoma in situ (DCIS) by risk of subsequent invasive breast cancer (IBC) could assist treatment planning and selection of surveillance protocols that accord with risk. We assessed the utility of routinely collected administrative data for stratifying by IBC risk following DCIS detection in a population-based screening programme to inform ongoing surveillance protocols. METHODS: A retrospective cohort design was used, employing linked data from the South Australian breast screening programme and cancer registry. Women entered the study at screening commencement and were followed until IBC diagnosis, death or end of the study period (1 December 2010), whichever came first. Routinely collected administrative data were analyzed to identify predictors of invasive breast cancer. RESULTS: Proportional hazards regression confirmed that the DCIS cohort had an elevated risk of IBC after adjustment for relevant confounders (HR = 4.0 (95% CL 3.4, 4.8)), which accorded with previous study results. Within the DCIS cohort, conservative breast surgery and earlier year of screening commencement were both predictive of an elevated invasive breast cancer risk. CONCLUSIONS: These linked cancer registry and administrative data gave plausible estimates of IBC risk following DCIS diagnosis, but were limited in coverage of key items for further risk stratification. It is important that the research utility of administrative datasets is maximized in their design phase in collaboration with researchers.

Breast cancer survival in New Zealand women.

BACKGROUND: The Quality Audit (BQA) of Breast Surgeons of Australia and New Zealand includes a broad range of data and is the largest New Zealand (NZ) breast cancer (BC) database outside the NZ Cancer Registry. We used BQA data to compare BC survival by ethnicity, deprivation, remoteness, clinical characteristic and case load. METHODS: BQA and death data were linked using the National Health Index. Disease-specific survival for invasive cases was benchmarked against Australian BQA data and NZ population-based survivals. Validity was explored by comparison with expected survival by risk factor. RESULTS: Compared with 93% for Australian audit cases, 5-year survival was 90% for NZ audit cases overall, 87% for Maori, 84% for Pacific and 91% for other. CONCLUSIONS: BC survival in NZ appears lower than in Australia, with inequities by ethnicity. Differences may be due to access, timeliness and quality of health services, patient risk profiles, BQA coverage and death-record methodology.