Cancer in First Nations people in Ontario, Canada: Incidence and mortality, 1991 to 2010.

BACKGROUND: This study aims to measure cancer incidence and mortality rates of Registered First Nations people in Ontario and compare them with those of other people in Ontario from 1991 to 2010. DATA AND METHODS: The federal Indian Register, the Ontario Cancer Registry and the Registered Persons Database were linked to develop a cohort of First Nations people diagnosed with cancer in Ontario. Sex-and site-specific age-standardized cancer incidence and mortality rates, and selected trends over time, were calculated. Rate ratios (RRs) were used to compare rates in First Nations peoples with those of other people in Ontario. RESULTS: The First Nations cohort comprised 194,392 people, with 6,859 cancer diagnoses. First Nations people had higher rates for certain cancers than others in Ontario: lung (males RR 1.19; females RR 1.47), colorectal (males RR 1.36; females RR 1.34) and kidney (males RR1.95; females RR 2.23). While lung cancer rates rose in First Nations females (annual percent change [APC] +2.67), they fell at a similar rate (APC -2.28) in males. Cervical cancer rates fell (APC -9.53) and approached the rate among other females in Ontario. Kidney cancer rates increased in First Nations people. DISCUSSION: First Nations people in Ontario have higher incidence and mortality for certain cancers compared with other people in Ontario. However, the declines in cervical cancer rates in First Nations females and lung cancer rates in First Nations males illustrate the likely impact of Pap test uptake and smoking cessation programs. Community-led efforts to develop culturally appropriate prevention and screening programs are essential to further reduce cancer rates in First Nations people.

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.

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.

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.

Vitamin D receptor polymorphisms and survival in patients with cutaneous melanoma: a population-based study.

Factors known to affect melanoma survival include age at presentation, sex and tumor characteristics. Polymorphisms also appear to modulate survival following diagnosis. Result from other studies suggest that vitamin D receptor (VDR) polymorphisms (SNPs) impact survival in patients with glioma, renal cell carcinoma, lung, breast, prostate and other cancers; however, a comprehensive study of VDR polymorphisms and melanoma-specific survival is lacking. We aimed to investigate whether VDR genetic variation influences survival in patients with cutaneous melanoma. The analysis involved 3566 incident single and multiple primary melanoma cases enrolled in the international population-based Genes, Environment, and Melanoma Study. Melanoma-specific survival outcomes were calculated for each of 38 VDR SNPs using a competing risk analysis after adjustment for covariates. There were 254 (7.1%) deaths due to melanoma during the median 7.6 years follow-up period. VDR SNPs rs7299460, rs3782905, rs2239182, rs12370156, rs2238140, rs7305032, rs1544410 (BsmI) and rs731236 (TaqI) each had a statistically significant (trend P values < 0.05) association with melanoma-specific survival in multivariate analysis. One functional SNP (rs2239182) remained significant after adjustment for multiple testing using the Monte Carlo method. None of the SNPs associated with survival were significantly associated with Breslow thickness, ulceration or mitosis. These results suggest that the VDR gene may influence survival from melanoma, although the mechanism by which VDR exerts its effect does not seem driven by tumor aggressiveness. Further investigations are needed to confirm our results and to understand the relationship between VDR and survival in the combined context of tumor and host characteristics.

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. Ontario's First Nations population experiences poorer cancer survival when compared to other Ontarians and strategies to reduce these inequalities must be developed and implemented.

Colorectal cancer incidence in the Aboriginal population of Ontario, 1998 to 2009.

BACKGROUND: Studies suggest that colorectal cancer incidence increased disproportionately among the Aboriginal population of Ontario relative to the general population. Using an ecological approach, this study examined colorectal cancer incidence for the 1998-to-2009 period among Aboriginal people living in Ontario. DATA AND METHODS: Based on their postal code when they were diagnosed, cases of colorectal cancer identified from the Ontario Cancer Registry were assigned to census geographic areas with high (33% or more) or low percentages of Aboriginal identity residents, using the Postal Code Conversion File Plus (PCCF+). To account for potential misclassification by the PCCF+, Indian reserves for which assignment through postal codes is likely to be accurate were identified. Age-standardized incidence rates and rate ratios were calculated to compare colorectal cancer incidence in high-Aboriginal identity areas or on Indian reserves with incidence in low-Aboriginal identity areas. RESULTS: Colorectal cancer incidence was significantly higher for residents of high- versus low-Aboriginal identity areas in Ontario (rate ratio for men = 1.44, 95% CI = 1.26-1.63; rate ratio for women = 1.42, 95% CI = 1.23-1.63), a disparity that persisted by age group. When the Aboriginal sample was limited to residents of Indian reserves, the difference was statistically significant only for men and for people aged 50 to 74. INTERPRETATION: The incidence of colorectal cancer differs across areas of Ontario with high and low percentages of Aboriginal identity residents.

Trends in incidence, mortality, and survival for kidney cancer in Canada, 1986-2007.

PURPOSE: Kidney cancer is one of the fastest rising cancers worldwide. We aimed to examine the trends in incidence, mortality, and survival for this cancer in Canada. METHODS: Incidence data for kidney cancer for 1986-2010 were from the Canadian Cancer Registry and the National Cancer Incidence Reporting System. These data were only available up to 2007 for the province of Quebec and consequently for the same year nationally, for Canada. Mortality data for 1986-2009 were from the Canadian Vital Statistics Death Database. Changes in age-standardized rates were analyzed by Joinpoint regression. Incidence rates were projected to 2025 using a Nordpred age-period-cohort model. Five-year relative survival ratios (RSR) were analyzed for 2004-2008 and earlier periods. RESULTS: Between 1986 and 2007, the age-standardized incidence rate (ASIR) per 100,000 rose from 13.4 to 17.9 in males and 7.7 to 10.3 in females. Annual increases in ASIR were greatest for age groups <65 years (males) and ≥65 years (females). The ASIRs increased significantly over time in both sexes for renal cell carcinoma (RCC) but not for other kidney cancer types. RCC rates are projected to increase until at least 2025. Mortality rates decreased only slightly in each sex since 1986 (0.4%/year in males; 0.8%/year in females). The 5-year RSR for kidney cancer was 68% but differed largely by morphology and age, and has increased slightly over time. CONCLUSIONS: The incidence rate of kidney cancer in Canada has risen since at least 1986, led largely by RCC. Increasing detection of incidental tumors, and growing obesity and hypertension rates are possible factors associated with this increase. Greater prevention of modifiable risk factors for kidney cancer is needed.

Cervical cancer incidence in ontario women: differing sociodemographic gradients by morphologic type (adenocarcinoma versus squamous cell).

OBJECTIVE: Identify patterns in cervical cancer incidence in Ontario according to neighborhood sociodemographic characteristics over time and by morphologic type. METHODS: Incident cases of cervical cancer diagnosed from 1991 to 2009 were obtained from the Ontario Cancer Registry. Population data and data on neighborhood sociodemographic characteristics were obtained from the Canadian Census. Age-standardized incidence rates (ASIR) and rate ratios (RRs) with 95% confidence intervals (CIs) were calculated for each sociodemographic characteristic, stratified by morphologic type (squamous cell carcinoma and adenocarcinoma) and time period of diagnosis. RESULTS: Incidence was 51% higher in the poorest neighborhoods compared with the richest (RR, 1.51; 95% CI, 1.42-1.61) and 7% higher in rural areas compared with urban (RR, 1.07; 95% CI, 1.01-1.13). Incidence of squamous cell carcinoma was significantly higher in the poorest neighborhoods compared with the richest (RR, 1.74; 95% CI, 1.61-1.88), a trend observed for all time periods, and in rural areas compared with urban (RR, 1.10; 95% CI, 1.02-1.18). For adenocarcinoma, ASIRs in the earlier time period (1991-1998) were higher in the poorest neighborhoods compared with richest (RR, 1.26; 95% CI, 1.01-1.57), whereas for the more recent time period (1999-2009), ASIRs were lower for women living in the poorest neighborhoods compared with the richest (RR, 0.82; 95% CI, 0.68-0.99). CONCLUSIONS: This study identified significantly higher incidence of cervical cancer in low-income neighborhoods in Ontario. The association was especially pronounced for squamous cell carcinoma and varied by time period for adenocarcinoma. Improvements to screening and prevention efforts against oncogenic human papillomavirus strains would increase the detection of cervical cancer, adenocarcinoma especially, and may further reduce cervical cancer incidence.

Vitamin D receptor polymorphisms in patients with cutaneous melanoma.

The vitamin D receptor (VDR) gene has been associated with cancer risk, but only a few polymorphisms have been studied in relation to melanoma risk and the results have been inconsistent. We examined 38 VDR gene single nucleotide polymorphisms (SNPs) in a large international multicenter population-based case-control study of melanoma. Buccal DNAs were obtained from 1,207 people with incident multiple primary melanoma and 2,469 with incident single primary melanoma. SNPs with known or suspected impact on VDR activity, haplotype tagging SNPs with ≥ 10% minor allele frequency in Caucasians, and SNPs reported as significant in other association studies were examined. Logistic regression was used to calculate the relative risks conferred by the individual SNP. Eight of 38 SNPs in the promoter, coding, and 3' gene regions were individually significantly associated with multiple primary melanoma after adjusting for covariates. The estimated increase in risk for individuals who were homozygous for the minor allele ranged from 25 to 33% for six polymorphisms: rs10875712 (odds ratios [OR] 1.28; 95% confidence interval (CI), 1.01-1.62), rs4760674 (OR 1.33; 95% CI, 1.06-1.67), rs7139166 (OR 1.26; 95%CI, 1.02-1.56), rs4516035 (OR 1.25; 95%CI, 1.01-1.55), rs11168287 (OR 1.27; 95%CI, 1.03-1.57) and rs1544410 (OR 1.30; 95%CI, 1.04-1.63); for two polymorphisms, homozygous carriers had a decreased risk: rs7305032 (OR 0.81; 95%CI 0.65-1.02) and rs7965281 (OR, 0.78; 95%CI, 0.62-0.99). We recognize the potential false positive findings because of multiple comparisons; however, the eight significant SNPs in our study outnumbered the two significant tests expected to occur by chance. The VDR may play a role in melanomagenesis.

Esophageal cancer in Canada: trends according to morphology and anatomical location.

BACKGROUND: Esophageal adenocarcinoma has one of the fastest rising incidence rates and one of the lowest survival rates of any cancer type in the Western world. However, in many countries, trends in esophageal cancer differ according to tumour morphology and anatomical location. In Canada, incidence and survival trends for esophageal cancer subtypes are poorly known. METHODS: Cancer incidence and mortality rates were obtained from the Canadian Cancer Registry, the National Cancer Incidence Reporting System and the Canadian Vital Statistics Death databases for the period from 1986 to 2006. Observed trends (annual per cent change) and five-year relative survival ratios were estimated separately for esophageal adenocarcinoma and squamous cell carcinoma, and according to location (upper, middle, or lower one-third of the esophagus). Incidence rates were projected up to the year 2026. RESULTS: Annual age-standardized incidence rates for esophageal cancer in 2004 to 2006 were 6.1 and 1.7 per 100,000 for males and females, respectively. Esophageal adenocarcinoma incidence rose by 3.9% (males) and 3.6% (females) per year for the period 1986 to 2006, with the steepest increase in the lower one-third of the esophagus (4.8% and 5.0% per year among males and females, respectively). In contrast, squamous cell carcinoma incidence declined by 3.3% (males) and 3.2% (females) per year since the early 1990s. The five-year relative survival ratio for esophageal cancer was 13% between 2004 and 2006, approximately a 3% increase since the period from 1992 to 1994. Projected incidence rates showed increases of 40% to 50% for esophageal adenocarcinoma and decreases of 30% for squamous cell carcinoma by 2026. DISCUSSION: Although esophageal cancer is rare in Canada, the incidence of esophageal adenocarcinoma has doubled in the past 20 years, which may reflect the increasing prevalence of obesity and gastroesophageal reflux disease. Declines in squamous cell carcinoma may be the result of the decreases in the prevalence of smoking in Canada. Given the low survival rates and the potential for further increases in incidence, esophageal adenocarcinoma warrants close attention.

Melanoma in adolescents and young adults (ages 15-39 years): United States, 1999-2006.

BACKGROUND: Invasive melanoma of the skin is the third most common cancer diagnosed among adolescents and young adults (aged 15-39 years) in the United States. Understanding the burden of melanoma in this age group is important to identifying areas for etiologic research and in developing effective prevention approaches aimed at reducing melanoma risk. METHODS: Melanoma incidence data reported from 38 National Program of Cancer Registries and/or Surveillance Epidemiology and End Results statewide cancer registries covering nearly 67.2% of the US population were used to estimate age-adjusted incidence rates for persons 15-39 years of age. Incidence rate ratios were calculated to compare rates between demographic groups. RESULTS: Melanoma incidence was higher among females (age-adjusted incidence rates = 9.74; 95% confidence interval 9.62-9.86) compared with males (age-adjusted incidence rates = 5.77; 95% confidence interval 5.68-5.86), increased with age, and was higher in non-Hispanic white compared with Hispanic white and black, American Indians/Alaskan Natives, and Asian and Pacific Islanders populations. Melanoma incidence rates increased with year of diagnosis in females but not males. The majority of melanomas were diagnosed on the trunk in all racial and ethnic groups among males but only in non-Hispanic whites among females. Most melanomas were diagnosed at localized stage, and among those melanomas with known histology, the majority were superficial spreading. LIMITATIONS: Accuracy of melanoma cases reporting was limited because of some incompleteness (delayed reporting) or nonspecific reporting including large proportion of unspecified histology. CONCLUSIONS: Differences in incidence rates by anatomic site, histology, and stage among adolescents and young adults by race, ethnicity, and sex suggest that both host characteristics and behaviors influence risk. These data suggest areas for etiologic research around gene-environment interactions and the need for targeted cancer control activities specific to adolescents and young adult populations.

MC1R genotype may modify the effect of sun exposure on melanoma risk in the GEM study.

We investigated whether MC1R genotype modifies the effect of sun exposure on melanoma risk in 1,018 cases with multiple melanomas (MPM) and 1,875 controls with one melanoma (SPM). There was some suggestion that MC1R genotype modified the effect of beach and water activities on MPM risk: ORs were 1.94 (95% CI 1.40-2.70) for any activities for no R variants and 1.39 (95% CI 1.05-1.84) with R variants (R151C, R160W, D294H, and D84E) (p for interaction 0.08). MC1R modification of sun exposure effects appeared most evident for MPM of the head and neck: for early life ambient UV, the OR was 4.23 (95% CI 1.76-10.20) with no R and 1.04 (95% CI 0.40-2.68) with R (p for interaction = 0.01; p for three-way interaction = 0.01). Phenotype modified the effect of sun exposure and MPM in a similar manner. We conclude that MC1R and pigmentary phenotype may modify the effects of sun exposure on melanoma risk on more continuously sun-exposed skin. Possible explanations include that risk may saturate with higher sun sensitivity for melanomas on continuously sun-exposed sites but continue to increase as sun exposure increases with lower sun sensitivity, or that sun-sensitive people adapt their behavior by increasing sun protection when exposed.

Sun behaviour in Canadian children: results of the 2006 National Sun Survey.

Childhood sun exposure is a particularly important determinant of skin cancer, yet little data are available for children. This paper describes sun behaviour among Canadian children for the summer of 2006. As part of the Second National Sun Survey (NSS2), 1,437 parents reported on the time spent in the sun, and the frequency of sun protection behaviours and sunburning for one of their children aged 1 to 12 years. Analysis was carried out using complex survey procedures in SAS and STATA. The majority of children (94%) spend at least 30 minutes in the sun on a typical summer day; however, regular sun protection is only commonly reported for young children (1 to 5 years) and involves covering their heads and wearing sunscreen (85%). The frequency of other protective behaviours is much lower, and sun protection decreases with age. Older children are also twice as likely to spend extended time in the sun and to get a sunburn. Among older children, boys are more likely to cover their heads and girls are more likely to wear sunscreen. Regular sun protection among Canadian children is low, given their sun exposure. Heavy reliance on sunscreen is consistent with previous reports and indicates that other measures, such as seeking shade and wearing protective clothing, need to be promoted. Riskier sun behaviour among older children may reflect decreased parental control, as well as changing attitudes and peer pressure, and highlights the importance of adult role models and targeted interventions for this age group.

Work-time sun behaviours among Canadian outdoor workers: results from the 2006 National Sun Survey.

The objective of the study was to describe summer work-related sun behaviours among Canadian outdoor workers. Information on time in the sun and sun protection practices at work during the summer of 2006 were collected from 1,337 outdoor workers aged 16-64 years as part of the Second National Sun Survey. Proportions (and 95% confidence intervals) were estimated using procedures appropriate for complex survey designs. Twenty-six percent of all Canadians, 39% of males and 33% of those aged 16-24 years work outdoors during the summer. Although 41% spend four or more hours daily in the sun at work, just over half always or often protect themselves by covering their heads (58%), wearing protective clothing (56%) or wearing sunglasses (54%), and only 29% use sunscreen. Males and those aged 16-24 spend the most work time in the sun but are the least likely to use protection. The prevalence of outdoor work and sun behaviours varies among regions. Study findings confirm the need for strategies to reduce time in the sun and increase the use of sun protection among outdoor workers. In order to be effective, these strategies must include both enhanced workplace policies and practice, and increased individual use of sun protection.

The Second National Sun Survey: overview and methods.

The Second National Sun Survey (NSS2) was carried out in 2006 to estimate ultraviolet radiation (UVR) exposure, sun protection and related knowledge, attitudes and beliefs among Canadians. This paper provides a detailed overview of NSS2 methods and discusses the strengths and limitations of the survey. The NSS2 consists of two questionnaires administered to two samples of adults (age 16+ years). The base sample provides in-depth information on UVR exposure, protective behaviours, tanning, and knowledge, attitudes and beliefs about sun safety for adults, as well as some sun behaviour information for a sample of their children aged 1-12 years. The shorter comparison sample facilitates direct comparison with the 1996 first national sun survey. Data were collected using computer-assisted telephone interviewing, and sample weights were computed for all respondents for estimation and analysis of both adult and child data. Base sample interviews were completed for 7,121 adults, of whom 1,437 reported on the sun behaviour of one of their children, and the comparison sample yielded 2,115 interviews. Response rates were 63% for both surveys. The NSS2 provides in-depth and up-to-date UVR exposure information among Canadians. The results of this survey will aid health promotion experts and policy-makers in developing effective programs to minimize UVR exposure. A public use data file and training in statistical analysis of the NSS2 has been made available to data analysts from across Canada. Key strengths and limitations identified in this survey will inform the development and implementation of future sun surveys.

Detection of later stage breast cancer in First Nations women in Ontario, Canada.

OBJECTIVE: To compare the distribution of stage at breast cancer diagnosis between First Nations (FN) and non-FN women, and to investigate factors associated with later diagnosis in FN women. METHODS: A case-case design was employed to compare FN women (N = 287) to a frequency-matched random sample of women (N = 671) from the general population diagnosed with breast cancer in the Ontario Cancer Registry. Women were matched (2:1) on period of diagnosis (1995-1999, 2000-2004), age at diagnosis (< 50 vs. > or = 50), and Regional Cancer Centre (RCC). Stage and data relevant to the determinants of stage were collected from medical charts at the RCCs. The association between stage (stage II + vs. I) and FN status was modeled using logistic regression analyses; for FN women, the association between risk factors and stage was examined. RESULTS: FN women (66%) were diagnosed with a later stage significantly more often than non-FN women (56%). FN women with a non-screened cancer (OR 5.03, 95% CI 2.48-10.21) and those who were overweight or obese (OR 2.98, 95% CI 1.27-6.98 and OR 4.46, 95% CI 1.95-10.21, respectively) were significantly more likely to be diagnosed at a later stage. Having a comorbidity reduced the odds of a later stage (OR 0.51, 95% CI 0.27-0.96) in FN women. CONCLUSION: This study demonstrates the need for FN women, in particular those who are not accessing the health care system, to participate in breast screening programs aimed at detecting breast cancers earlier with a better prognosis. These findings suggest that the cancer care system in Ontario should better target this population through increasing awareness and access to screening.

Influence of Preexisting Diabetes on Survival After a Breast Cancer Diagnosis in First Nations Women in Ontario, Canada.

PURPOSE: Survival after a breast cancer diagnosis is poorer in First Nations women with a preexisting comorbidity compared with comorbidity-free First Nations women in Ontario, Canada. Given the high prevalence of diabetes in this population, it is important to determine whether preexisting diabetes is related to poorer survival after a breast cancer diagnosis. METHODS: All First Nations women were identified from a cohort of First Nations people diagnosed with breast cancer in diagnostic periods-1995 to 1999 and 2000 to 2004-and seen at a regional cancer program (RCP) in Ontario. Preexisting diabetes status and other factors, such as age at diagnosis, body mass index, and stage at diagnosis, were collected from medical charts at the regional cancer programs. The association between preexisting diabetes and First Nations status was examined by each of the demographic, personal, tumor, and treatment factors using logistic regression models. Survival was compared between First Nations women with (n = 67) and without (n = 215) preexisting diabetes, adjusted by significant study factors using a Cox proportional hazards regression model. RESULTS: The 5-year survival rate among First Nations women with diabetes was 59.8% versus 78.7% among those without diabetes (P < .01). Preexisting diabetes significantly increased the risk of death among First Nations women with breast cancer (hazard ratio, 1.87; 95% CI, 1.12 to 3.13) after adjustment for age group, period of diagnosis, body mass index, other comorbidities at diagnosis, and stage. CONCLUSION: This study recommends awareness of this survival discrepancy among the treatment team for First Nations patients with breast cancer with preexisting diabetes.

Changing incidence of AIDS-related Kaposi sarcoma and non-Hodgkin lymphoma in Ontario, Canada.

OBJECTIVE: To examine the influence of the AIDS epidemic on the incidence of Kaposi sarcoma (KS) and non-Hodgkin lymphoma (NHL) in Ontario. METHODS: Age-standardized incidence rates for KS and NHL from 1981 to 2000 were calculated from the population-based Ontario Cancer Registry. AIDS cases were extracted from Ontario Ministry of Health and Long-Term Care reports. HIV death data were obtained from the Ontario Cancer Registry. RESULTS: KS was a rare cancer before the 1980s; however, incidence increased sharply between 1985 and 1995 by 13.8% per year. Thereafter, incidence rates fell close to those in the early 1980s. NHL incidence in males increased steadily during the 1980s at 3.2% per year and then slowed beyond 1990. In males aged 30-44, NHL incidence rose from 1981 to 1990 (8.8% per year) and then fell (-2.5%) thereafter. NHL and KS cases represented one-third of HIV deaths. CONCLUSIONS: The AIDS epidemic, the introduction of antiretroviral therapies, and the decrease in HIV infection rates explain the rise and decline of KS incidence in Ontario. NHL incidence trends are more complex, although the AIDS epidemic explains the trends observed in younger men (in whom AIDS is more common), and for the AIDS-related subtypes.

Population-based study of natural variation in the melanocortin-1 receptor gene and melanoma.

Natural variation in the coding region of the melanocortin-1 receptor (MC1R) gene is associated with constitutive pigmentation phenotypes and development of melanoma and nonmelanoma skin cancers. We investigated the effect of MC1R variants on melanoma using a large, international population-based study design with complete determination of all MC1R coding region variants. Direct sequencing was completed for 2,202 subjects with a single primary melanoma (controls) and 1,099 subjects with second or higher-order primary melanomas (cases) from Australia, the United States, Canada, and Italy. We observed 85 different MC1R variants, 10 of which occurred at a frequency >1%. Compared with controls, cases were more likely to carry two previously identified red hair ("R") variants [D84E, R151C, R160W, and D294H; odds ratio (OR), 1.6; 95% confidence interval (95% CI), 1.1-2.2]. This effect was similar among individuals carrying one R variant and one r variant (defined as any non-R MC1R variant; OR, 1.6; 95% CI, 1.3-2.2) and among those carrying only one R variant (OR, 1.5; 95% CI, 1.1-1.9). There was no statistically significant association among those carrying only one or two r variants. Effects were similar across geographic regions and categories of pigmentation characteristics or number of moles. Our results confirm that MC1R is a low-penetrance susceptibility locus for melanoma, show that pigmentation characteristics may not modify the relationship of MC1R variants and melanoma risk, and suggest that associations may be smaller than previously reported in part due to the study design.

Assessing a ban on the use of UV tanning devices among adolescents in Ontario, Canada: first-year results.

OBJECTIVES: To describe the effect of the first year of a ban on UV tanning device (beds, lamps) use among those under 18 years of age in Ontario, Canada. METHODS: Online questionnaires were completed by adolescents in grades 7 to 12, aged less than 18 years: one when the ban was enacted (May 2014) and a second a year later (May 2015). Questionnaires asked grade, age, sex, and about use of UV tanning devices in the previous year. Recent users were asked about length, frequency, and location of use; service refusals and reasons; awareness of signs/warning labels; and use of eye protection. Weighted estimates and confidence intervals were generated. RESULTS: There were 1561 participants in 2014 and 2305 in 2015. No reduction was observed in UV tanning device use (6.9% vs. 7.9%) in the 12 months preceding the survey. In 2015, most respondents used UV tanning devices in beauty establishments, which was a shift away from gyms and fitness centres as seen in 2014. Non-significant increases occurred in the proportions noticing warning signs/labels (57% vs. 71%), required to wear eye protection (92% vs. 99%), and refused service (17% vs. 21%). Most adolescents who were refused service did not use tanning devices that year (72%). CONCLUSION: Use did not change in the year following enactment of a ban on UV tanning devices among youth in Ontario. The ban did lead to improvements in service refusal, awareness of warning signage, and use of eye protection. As service refusal deterred future use, enhanced enforcement is important.