Diana R. Withrow

Cancer survival among First Nations people of Ontario, Canada (1968-2007).

We aimed to compare cancer survival in Ontario First Nations people to that in other Ontarians for five major cancer types: colorectal, lung, cervix, breast and prostate. A list of registered or “Status” Indians in Ontario was used to create a cohort of over 140,000 Ontario First Nations people. Cancers diagnosed in cohort members between 1968 and 2001 were identified from the Ontario Cancer Registry, with follow‐up for death until December 31st, 2007. Flexible parametric modeling of the hazard function was used to compare the survival experience of the cohort to that of other Ontarians. We considered changes in survival from the first half of the time period (1968–1991) to the second half (1992–2001). For other Ontarians, survival had improved over time for every cancer site. For the First Nations cohort, survival improved only for breast and prostate cancers; it either declined or remained unchanged for the other cancers. For cancers diagnosed in 1992 or later, all‐cause and cause‐specific survival was significantly poorer for First Nations people diagnosed with breast, prostate, cervical, colorectal (male and female) and male lung cancers as compared to their non‐First Nations peers. For female lung cancer, First Nations women appeared to have poorer survival; however, the result was not statistically significant. Ontarios First Nations population experiences poorer cancer survival when compared to other Ontarians and strategies to reduce these inequalities must be developed and implemented.

A critical review of methods for assessing cancer survival disparities in indigenous population

PURPOSEnAn increasing cancer burden among indigenous populations has led to a growing literature about survival disparities between indigenous and nonindigenous persons. We aim to describe and appraise methods used to measure cancer survival in indigenous persons in the United States, Canada, Australia, and New Zealand.nnnMETHODSnWe searched Medline, Web of Science, and EMBASE for articles published between 1990 and 2015 that estimated survival in populations indigenous to one of these four countries. We gathered information about data sources, analytical methods, and the extent to which threats to validity were discussed.nnnRESULTSnThe search retrieved 83 articles. The most common approach to survival analysis was cause-specific survival (nxa0= 49). Thirty-eight articles measured all-cause survival and 11 measured excess mortality attributable to cancer (relative survival). Three sources of information bias common to all studies (ethnic misclassification, incomplete case ascertainment, and incomplete death ascertainment) were acknowledged in a minority of articles.nnnCONCLUSIONSnThe methodological considerations we present here are shared with studies of cancer survival across other subpopulations. We urge future researchers on this and related topics to clearly describe their data sources, to justify analytic choices, and to fully discuss the potential impact of those choices on the results and interpretation.

Choice of relative or cause-specific approach to cancer survival analysis impacts estimates differentially by cancer type, population, and application: evidence from a Canadian population-based cohort study

BackgroundCause-specific (CS) and net survival in a relative survival framework (RS) are two of the most common methods for estimating cancer survival. In this paper, we assess the differences in results produced by two permutations of cause-specific and relative survival applied to estimating cancer survival and disparities in cancer survival, using data from First Nations and non-Aboriginal populations in Canada.MethodsSubjects were members of the 1991 Canadian Census Mortality Cohort, a population-based cohort of adult respondents to the 1991 Long Form Census who have been followed up for incident cancers and death through linkage to administrative databases. We compared four methods: relative survival analyses with ethnicity-specific life tables (RS-ELT); relative survival with general population life tables (RS-GLT); cause-specific survival with a broad definition of cancer death (CS-Broad); and cause-specific survival with a narrow definition of cause of death (CS-Narrow) and applied these to the nine most common cancers among First Nations.ResultsApart from breast and prostate cancers, RS-ELT, RS-GLT, and CS-Broad tended to produce similar estimates of age-standardized five-year survival, whereas CS-Narrow yielded higher estimates of survival. CS-Narrow estimates were particularly unlike those based on the other methods for cancers of the digestive and respiratory tracts. Estimates of disparities in survival were generally comparable across the four methods except for breast and prostate cancers.ConclusionsCancer surveillance efforts in sub-populations defined by race, ethnicity, geography, socioeconomic status, or similar factors are necessary for identifying disparities and monitoring progress toward reducing them. In the absence of routine monitoring of cancer survival and cancer survival disparities in these populations, estimates generated by different methods will inevitably be compared over time and across populations. In this study, we demonstrate that caution should be exercised in making these comparisons, particularly in interpreting cause-specific survival rates with an unknown or narrow definition of cancer death and in estimates of breast and prostate cancer survival and/or disparities in survival generated by different methods.Background Cause-specific (CS) and net survival in a relative survival framework (RS) are two of the most common methods for estimating cancer survival. In this paper, we assess the differences in results produced by two permutations of cause-specific and relative survival applied to estimating cancer survival and disparities in cancer survival, using data from First Nations and non-Aboriginal populations in Canada. Methods Subjects were members of the 1991 Canadian Census Mortality Cohort, a population-based cohort of adult respondents to the 1991 Long Form Census who have been followed up for incident cancers and death through linkage to administrative databases. We compared four methods: relative survival analyses with ethnicity-specific life tables (RS-ELT); relative survival with general population life tables (RS-GLT); cause-specific survival with a broad definition of cancer death (CS-Broad); and cause-specific survival with a narrow definition of cause of death (CS-Narrow) and applied these to the nine most common cancers among First Nations. Results Apart from breast and prostate cancers, RS-ELT, RS-GLT, and CS-Broad tended to produce similar estimates of age-standardized five-year survival, whereas CS-Narrow yielded higher estimates of survival. CS-Narrow estimates were particularly unlike those based on the other methods for cancers of the digestive and respiratory tracts. Estimates of disparities in survival were generally comparable across the four methods except for breast and prostate cancers. Conclusions Cancer surveillance efforts in sub-populations defined by race, ethnicity, geography, socioeconomic status, or similar factors are necessary for identifying disparities and monitoring progress toward reducing them. In the absence of routine monitoring of cancer survival and cancer survival disparities in these populations, estimates generated by different methods will inevitably be compared over time and across populations. In this study, we demonstrate that caution should be exercised in making these comparisons, particularly in interpreting cause-specific survival rates with an unknown or narrow definition of cancer death and in estimates of breast and prostate cancer survival and/or disparities in survival generated by different methods. Electronic supplementary material The online version of this article (doi:10.1186/s12963-017-0142-4) contains supplementary material, which is available to authorized users.

Cancer Survival Disparities Between First Nation and Non-Aboriginal Adults in Canada: Follow-up of the 1991 Census Mortality Cohort

Background: The burden of cancer among indigenous people in Canada has been understudied due to a lack of ethnic identifiers in cancer registries. We compared cancer survival among First Nations to that among non-Aboriginal adults in Canada in the first national study of its kind to date. Methods: A population-based cohort of approximately 2 million respondents to the 1991 Canadian Long Form Census was followed for cancer diagnoses and deaths using probabilistic linkage to cancer and death registries until 2009. Excess mortality rate ratios (EMRR) and 5-year age-standardized relative survival rates were calculated for 15 cancers using age, sex, ethnicity, and calendar-time–specific life tables derived from the cohort at large. Results: First Nations diagnosed with cancers of the colon and rectum, lung and bronchus, breast, prostate, oral cavity and pharynx, cervix, ovary, or with non-Hodgkin lymphoma and leukemia all had significantly poorer 5-year survival than their non-Aboriginal peers. For colorectal cancer, a significant disparity was only present between 2001 and 2009 (EMRR: 1.52; 95% CI, 1.28–1.80). For prostate cancer, a significant disparity was only present between 1992 and 2000 (EMRR: 2.76; 95% CI, 1.81–4.21). Adjusting for income and rurality had little impact on the EMRRs. Conclusions: Compared with non-Aboriginals, First Nations people had poorer survival for 14 of 15 of the most common cancers, and disparities could not be explained by income and rurality. Impact: The results of this study can serve as a benchmark for monitoring progress toward narrowing the gap in survival. Cancer Epidemiol Biomarkers Prev; 26(1); 145–51. ©2016 AACR.

Infant and Youth Mortality Trends by Race/Ethnicity and Cause of Death in the United States

Importance The United States has higher infant and youth mortality rates than other high-income countries, with striking disparities by racial/ethnic group. Understanding changing trends by age and race/ethnicity for leading causes of death is imperative for focused intervention. Objective To estimate trends in US infant and youth mortality rates from 1999 to 2015 by age group and race/ethnicity, identify leading causes of death, and compare mortality rates with Canada and England/Wales. Design, Setting, and Participants This descriptive study analyzed death certificate data from the US National Center for Health Statistics, Statistics Canada, and the UK Office of National Statistics for all deaths among individuals younger than 25 years. The study took place from January 1, 1999, to December 31, 2015, and analyses started in September 2017. Exposures Race/ethnicity. Main Outcomes and Measures Average annual percent changes in mortality rates from 1999 to 2015 and absolute rate change between 1999 to 2002 and 2012 to 2015 for each age group, race/ethnicity, and cause of death. Results Among individuals from birth to age 24 years, 1 169 537 deaths occurred in the United States, 80 540 in Canada, and 121 183 in England/Wales from 1999 to 2015. In the United States, 64% of deaths occurred in male individuals and 52.6% occurred in white individuals (25.1% deaths occurred in black individuals and 17.9% in Latino individuals). All-cause mortality declined for all age groups (infants younger than 1 year [38.5% of deaths], children aged 1-9 years [10.6%], early adolescents aged 10-14 years [5%], late adolescents aged 15-19 years [17.7%], and young adults aged 20-24 years [28.1%]) in the United States, Canada, and England/Wales from 1999 to 2015. However, rates were highest in the United States. Within the United States, annual declines in all-cause mortality rates occurred among all age groups of black, Latino, and white individuals, except for white individuals aged 20 to 24 years, whose rates remained stable. Mortality rates declined across most major causes of death from 1999 to 2002 and 2012 to 2015, with notable declines observed for sudden infant death syndrome, unintentional injury death, and homicides. Among infants, unintentional suffocation and strangulation in bed increased (difference between 2012-2015 and 1999-2002 range, 6.11-29.03 per 100 000). Further, suicide rates among Latino and white individuals aged 10 to 24 years (range, 0.21-2.63 per 100 000) and black individuals aged 10 to 19 years (range, 0.10-0.45 per 100 000) increased, as did unintentional injury deaths in white young adults (0.79 per 100 000). The rise in unintentional injury deaths is attributed to increases in drug poisonings and was also observed in black and Latino young adults. Conclusions and Relevance Mortality rates in the United States have generally declined for infants and youths from 1999 to 2015 owing to reductions in sudden infant death syndrome, unintentional injury death, and homicides. However, US mortality rates remain higher than Canada and England/Wales, with particularly elevated rates among black and American Indian/Alaskan Native youth. Further, there is a concerning increase in suicide and drug poisoning death rates among US adolescents and young adults.

Association of Treatment for Hodgkin Lymphoma With Estrogen Receptor Status of Subsequent Breast Cancers

Results | We identified 401 interventional prostate cancer clinical trials with an overall survival end point from clinicaltrials .gov (Table). Overall, 47.9% (192) of these trials used sCr alone and/or required participants to have an ANC of 1.5 × 109 cells/L or higher. Specifically, 25.2% (101) of the trials used sCr alone to determine eligibility and 41.4% (166) of the trials required patients to have an ANC of 1.5 × 109 cells/L or higher. The use of sCr alone and/or an ANC cutoff level of 1.5 × 109 cells/L or higher to determine eligibility was more common in trials that were sponsored by academic investigators or cooperative groups vs industry (P < .001), were phase 1 or 2 vs 3 (P < .02), had lower accrual (P < .001), or had at least 1 treatment arm that was considered high toxicity (P < .001) (Table).

Cancer incidence and survival among Métis adults in Canada: results from the Canadian census follow-up cohort (1992–2009)

BACKGROUND: Métis people are 1 of 3 Aboriginal groups recognized by the Canadian constitution. We estimated site-specific incidence rates and survival for the most common cancers among Métis adults in Canada and compared these with rates among non-Aboriginal adults in Canada. METHODS: We examined responses to the 1991 long-form census, including self-reported Métis ancestry linked to national mortality and cancer databases for followup from 1992 to 2009. We estimated age-standardized incidence rates and 5-year relative survival. We determined relative risk (RR) of cancer among Métis and non-Aboriginal adults using Poisson regression, and estimated excess mortality rate ratios using ethnicity-specific life tables. RESULTS: For all cancers and both sexes combined, cancer incidence was similar for Métis and non-Aboriginal adults. However, incidence was significantly higher among Métis adults than among non-Aboriginal adults for the following cancers: female breast (RR 1.18, 95% confidence interval [CI] 1.02–1.37), lung (RR 1.34, 95% CI 1.18–1.52), liver (RR 2.09, 95% CI 1.30–3.38), larynx (RR 1.60, 95% CI 1.03–2.48), gallbladder (RR 2.35, 95% CI 1.12–4.96) and cervix (RR 1.84, 95% CI 1.23–2.76). Métis people had poorer survival for prostate cancer (excess mortality rate ratio 2.60, 95% CI 1.52–4.46). INTERPRETATION: We found higher incidence for several cancers and poorer survival after prostate cancer among Métis adults. Several of these disparities may be related to lifestyle factors (including tobacco use, obesity and lack of cancer screening), providing evidence to support development of public health policy and health care to address cancer burden in the Métis people of Canada.

Measuring cancer in indigenous populations

It is estimated that there are 370 million indigenous peoples in 90 countries globally. Indigenous peoples generally face substantial disadvantage and poorer health status compared with nonindigenous peoples. Population-level cancer surveillance provides data to set priorities, inform policies, and monitor progress over time. Measuring the cancer burden of vulnerable subpopulations, particularly indigenous peoples, is problematic. There are a number of practical and methodological issues potentially resulting in substantial underestimation of cancer incidence and mortality rates, and biased survival rates, among indigenous peoples. This, in turn, may result in a deprioritization of cancer-related programs and policies among these populations. This commentary describes key issues relating to cancer surveillance among indigenous populations including 1) suboptimal identification of indigenous populations, 2) numerator-denominator bias, 3) problems with data linkage in survival analysis, and 4) statistical analytic considerations. We suggest solutions that can be implemented to strengthen the visibility of indigenous peoples around the world. These include acknowledgment of the central importance of full engagement of indigenous peoples with all data-related processes, encouraging the use of indigenous identifiers in national and regional data sets and mitigation and/or careful assessment of biases inherent in cancer surveillance methods for indigenous peoples.

CANCER INCIDENCE IN FIRST NATIONS AND MéTIS ADULTS IN CANADA: FOLLOW-UP OF THE 1991 CENSUS MORTALITY COHORT

Introduction Cancer incidence amongst First Nations has historically been lower than that in the general population, but preliminary province-level evidence suggests it is rising to meet or exceed that in the general population. Objectives We aim to estimate incidence rates of lung, prostate, breast and colorectal cancers in First Nations and Métis (FN&M) and compare these to the rates in non-Aboriginal Canadians nationwide. Methods A cohort of 1991 Long Form Census respondents was probabilistically linked to the Canadian Cancer Registry (1992 to 2003) and the Canadian Mortality Database (1992 to 2006). Age-standardized, site-specific incidence rates and time trends will be generated over the next 4 months and results will be available for presentation. This will be the first national study of cancer incidence in FN&M. Further, this linked cohort provides a rare opportunity to include groups typically under-represented in health research (e.g. Métis and non-Status Indians) since FN&M will be identified based on self-report of Aboriginal ancestry, Registration and band membership in the Census. Results The cohort includes 2.7 million adults 25 and older on Census day in 1991, equivalent to a 15% sample of the population of that age at the time. Of these, approximately 62,000 reported either First Nations ancestry or are registered under the Indian Act of Canada. Preliminary analyses show that crudely, cancer incidence from 1992 to 2003 was higher in non-Aboriginals than in FN&M nationwide. FN&M have similar incidence of breast and colorectal cancers, both lower than the general population. The Métis have significantly lower incidence of prostate cancer than the general population, but significantly higher rates than First Nations. Incidence rates of lung cancer in Métis are comparable to those in the general population, while First Nations have lower lung cancer incidence. Conclusions Using an innovative approach, this study will provide much needed data to inform effective, culturally-appropriate cancer prevention and control activities for FN&M in Canada. New cancer incidence data will help justify and re-prioritize FN&M cancer programs by identifying issues that require the most attention.