Progress in cancer control leads to a substantial number of cancer deaths avoided in Canada

It is currently not known how many more cancer deaths would have occurred among Canadians if cancer mortality rates were unchanged following various modern human interventions. The objective of this study was to estimate the number of cancer deaths that have been avoided in Canada since the age-standardized overall cancer mortality rate peaked in 1988. We applied the age-specific overall cancer mortality rates from 1988 to the Canadian population for all subsequent years to estimate the number of expected deaths. Avoided cancer deaths were estimated as the difference between the observed and expected number of cancer deaths for each year. Since 1988, there have been 372 584 (standardized mortality ratio = 0.77) and 120 045 (standardized mortality ratio = 0.90) avoided cancer deaths in males and females, respectively (492 629 total). Nearly half a million cancer deaths have been avoided in Canada since the overall cancer mortality rate peaked, which demonstrates the exceptional progress made in modern cancer control in Canada.

Lifetime probability of developing cancer and dying from cancer in Canada, 1997 to 2020

Background

The lifetime probabilities of developing (LPdev) cancer and dying (LPdying) from cancer are useful summary statistics that describe the impact of cancer within a population. This study aims to present detailed LPdev and LPdying for cancer by sex and cancer type and to describe changes in these lifetime probabilities over time among the Canadian population.

Data and methods

Cancer incidence data (1997 to 2018) were obtained from the Canadian Cancer Registry. All-cause and cancer mortality data (1997 to 2020) were obtained from the Canadian Vital Statistics - Death Database. LPdev and LPdying were calculated using the DevCan software, and trends over time were estimated using Joinpoint.

Results

The LPdev for all cancers combined was 44.3% in Canada in 2018, with all results excluding Quebec. At the age of 60, the conditional probability of developing cancer was very similar (44.0% for males and 38.2% for females). The LPdying was 22.5% among the Canadian population in 2020, while the probability of dying from cancer conditional on surviving until age 60 was 25.1% for males and 20.5% for females. Generally, males experienced higher LPdev and LPdying for most specific cancers compared with females.

Interpretation

LPdev and LPdying for cancer mirror cancer incidence and mortality rates. Cancer-specific changes in these probabilities over time are indicative of the cancer trends resulting from cancer prevention, screening, detection, and treatment. These changes in LPdev and LPdying provide insight into the shifting landscape of the Canadian cancer burden.

Update on cancer incidence trends in Canada, 1984 to 2017

This paper highlights findings on cancer trends from the Canadian Cancer Statistics 2021 report. Trends were measured using annual percent change (APC) of age-standardized incidence rates. Overall, cancer incidence rates are declining (-1.1%) but the findings are specific to the type of cancer and patient sex. For example, in males, the largest decreases per year were for prostate (-4.4%), colorectal (-4.3%), lung (-3.8%), leukemia (-2.6%) and thyroid (-2.4%) cancers. In females, the largest decreases were for thyroid (-5.4%), colorectal (-3.4%) and ovarian (-3.1%) cancers.

Projected estimates of cancer in Canada in 2022

BACKGROUND

Regular cancer surveillance is crucial for understanding where progress is being made and where more must be done. We sought to provide an overview of the expected burden of cancer in Canada in 2022.

METHODS

We obtained data on new cancer incidence from the National Cancer Incidence Reporting System (1984-1991) and Canadian Cancer Registry (1992-2018). Mortality data (1984-2019) were obtained from the Canadian Vital Statistics - Death Database. We projected cancer incidence and mortality counts and rates to 2022 for 22 cancer types by sex and province or territory. Rates were age standardized to the 2011 Canadian standard population.

RESULTS

An estimated 233 900 new cancer cases and 85 100 cancer deaths are expected in Canada in 2022. We expect the most commonly diagnosed cancers to be lung overall (30 000), breast in females (28 600) and prostate in males (24 600). We also expect lung cancer to be the leading cause of cancer death, accounting for 24.3% of all cancer deaths, followed by colorectal (11.0%), pancreatic (6.7%) and breast cancers (6.5%). Incidence and mortality rates are generally expected to be higher in the eastern provinces of Canada than the western provinces.

INTERPRETATION

Although overall cancer rates are declining, the number of cases and deaths continues to climb, owing to population growth and the aging population. The projected high burden of lung cancer indicates a need for increased tobacco control and improvements in early detection and treatment. Success in breast and colorectal cancer screening and treatment likely account for the continued decline in their burden. The limited progress in early detection and new treatments for pancreatic cancer explains why it is expected to be the third leading cause of cancer death in Canada.

Projected estimates of cancer in Canada in 2020

BACKGROUND

Cancer projections to the current year help in policy development, planning of programs and allocation of resources. We sought to provide an overview of the expected incidence and mortality of cancer in Canada in 2020 in follow-up to the Canadian Cancer Statistics 2019 report.

METHODS

We obtained incidence data from the National Cancer Incidence Reporting System (1984-1991) and Canadian Cancer Registry (1992-2015). Mortality data (1984-2015) were obtained from the Canadian Vital Statistics - Death Database. All databases are maintained by Statistics Canada. Cancer incidence and mortality counts and age-standardized rates were projected to 2020 for 23 cancer types by sex and geographic region (provinces and territories) for all ages combined.

RESULTS

An estimated 225 800 new cancer cases and 83 300 cancer deaths are expected in Canada in 2020. The most commonly diagnosed cancers are expected to be lung overall (29 800), breast in females (27 400) and prostate in males (23 300). Lung cancer is also expected to be the leading cause of cancer death, accounting for 25.5% of all cancer deaths, followed by colorectal (11.6%), pancreatic (6.4%) and breast (6.1%) cancers. Incidence and mortality rates will be generally higher in the eastern provinces than in the western provinces.

INTERPRETATION

The number of cancer cases and deaths remains high in Canada and, owing to the growing and aging population, is expected to continue to increase. Although progress has been made in reducing deaths for most major cancers (breast, prostate and lung), there has been limited progress for pancreatic cancer, which is expected to be the third leading cause of cancer death in Canada in 2020. Additional efforts to improve uptake of existing programs, as well as to advance research, prevention, screening and treatment, are needed to address the cancer burden in Canada.

At-a-glance - Cancer trends in Canada, 1984 to 2015

Examining incidence trends of all cancers combined in order to understand cancer trends can be misleading, as patterns can vary across individual cancer types. This paper highlights findings on trends over time from Canadian Cancer Statistics 2019, as measured by the annual percent change (APC) of age-standardized incidence rates. Among the results were a recent increase in thyroid cancer in males (APC: 6.4%, 1997-2015), as well as decreases in prostate cancer (APC: -9.1%, 2011-2015) and cervical cancer (APC: -3.3%, 2010-2015).

Cancer incidence, mortality, and stage at diagnosis in First Nations living in Manitoba

BACKGROUND

In the present study, we examined breast (bca) and colorectal cancer (crc) incidence and mortality and stage at diagnosis for First Nations (fn) individuals and all other Manitobans (aoms).

METHODS

Several population-based databases were linked to determine ethnicity and to calculate age-standardized incidence and mortality rates. Logistic regression was used to compare bca and crc stage at diagnosis.

RESULTS

From 1984-1988 to 2004-2008, the incidence of bca increased for fn and aom women. Breast cancer mortality increased for fn women and decreased for aom women. First Nations women were significantly more likely than aom women to be diagnosed at stages iii-iv than at stage i [odds ratio (or) for women ≤50 years of age: 3.11; 95% confidence limits (cl): 1.20, 8.06; or for women 50-69 years of age: 1.72; 95% cl: 1.03, 2.88). The incidence and mortality of crc increased for fn individuals, but decreased for aoms. First Nations status was not significantly associated with crc stage at diagnosis (or for stages i-ii compared with stages iii-iv: 0.98; 95% cl: 0.68, 1.41; or for stages i-iii compared with stage iv: 0.91; 95% cl: 0.59, 1.40).

CONCLUSIONS

Our results underscore the need for improved cancer screening participation and targeted initiatives that emphasis collaboration with fn communities to reduce barriers to screening and to promote healthy lifestyles.

Topical 5% Imiquimod in the Treatment of Lentigo Maligna

Background:

Standard treatment for lentigo maligna (LM) is surgical excision with 5 to 10 mm margins. This can be cosmetically disfiguring. Imiquimod locally induces Toll-like receptors to release cytokines that destroy neoplastic melanocytes.

Objective:

The off-label use of topical 5% imiquimod cream may provide an alternative to surgery. This study reviews the use of imiquimod to treat LM.

Methods:

A 5-year retrospective and prospective chart analysis was conducted. Pretreatment biopsies confirmed the diagnosis. Treatment was individualized for each patient. Posttreatment biopsies and dermoscopy determined clearance of LM.

Results:

Twenty-seven patients were reviewed. There were 20 responders (74.1%) and 7 failures. The mean tumor size (area of an ellipse) was 6.69 cm2, and the mean treatment duration was 17.68 weeks. Neither the size of the tumor ( p = .86) nor treatment duration ( p = .18) was related to resolution of the lesion.

Conclusion:

Imiquimod is an effective treatment for LM that provides patients with a cosmetically favorable outcome when standard surgery is not an option.

Risk of colorectal cancer after the diagnosis of prostate cancer: A population-based study

BACKGROUND

A rigorous assessment of the risk of colorectal cancer (CRC) among prostate cancer (PC) survivors that controls for important confounding factors and competing risks is necessary to determine the risk of CRC in this population and to inform screening guidelines.

METHODS

With data from Manitoba, Canada, subjects diagnosed with PC as their first cancer between 1987 and 2009 were age-matched with up to 5 men with no history of invasive cancer on the PC diagnosis date. Subjects were followed to the date of diagnosis of CRC or another cancer, death, emigration, or the study endpoint (December 31, 2009). Competing risk proportional hazards models were used to compare the CRC incidence between those with PC and those without PC with the following model covariates: history of lower gastrointestinal endoscopy, frequency of health care visits, diabetes, and socioeconomic status. Mutually exclusive competing outcomes included CRC, another primary cancer, and death.

RESULTS

For a total of 559,081 person-years, 14,164 men with PC and 69,051 men without PC were followed. Men diagnosed with PC had an increased risk of a subsequent diagnosis of CRC (all CRC: hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.02-1.27; rectal cancer: HR, 1.36; 95% CI, 1.09-1.71). The treatment of PC with radiation was associated with an increased risk for rectal cancer (HR, 2.06; 95% CI, 1.42-2.99) in comparison with PC cases not treated with radiation.

CONCLUSIONS

The risk of CRC is increased after a diagnosis of PC and is highest for rectal cancer among those treated with radiation. CRC screening should be considered soon after the diagnosis of PC, especially for men planning for radiotherapy.

Reducing income-related inequities in colorectal cancer screening: lessons learned from a retrospective analysis of organised programme and non-programme screening delivery in Winnipeg, Manitoba

OBJECTIVE

We examined organised colorectal cancer (CRC) screening programme and non-programme faecal occult blood test (FOBT) use from 2008 to 2012 for individuals living in Winnipeg, Manitoba, by area-level income.

SETTING

Winnipeg, Manitoba, a region with universal healthcare and an organised CRC screening programme.

PARTICIPANTS

Individuals who had a non-programme FOBT were identified from the Provincial Medical Claims database. Individuals who had a programme FOBT were identified from the provincial screening registry. Census data were used to determine average household income based on area of residence.

STATISTICAL ANALYSIS

Trends in age-standardised FOBT rates were examined using Joinpoint Regression. Logistic regression was performed to explore the association between programme and non-programme FOBT use and income quintile.

RESULTS

FOBT use (non-programme and programme) increased from 32.2% in 2008 to 41.6% in 2012. Individuals living in the highest income areas (Q5) were more likely to have a non-programme FOBT compared with those living in other areas. Individuals living in areas with the lowest average income level (Q1) were less likely to have had programme FOBT than those living in areas with the highest average income level (OR 0.80, 95% CI 0.77 to 0.82). There was no difference in programme FOBT use for individuals living in areas with the second lowest income level (Q2) compared with those living in areas with the highest. Individuals living in areas with a moderate-income level (Q3 and Q4) were more likely to have had a programme FOBT compared with those living in an area with the highest income level (OR 1.12, 95% CI 1.09 to 1.15 for Q3 and OR 1.10, 95% CI 1.07 to 1.13 for Q4).

CONCLUSIONS

Inequities by income observed for non-programme FOBTs were largely eliminated when programme FOBTs were examined. Targeted interventions within organised screening programmes in very low-income areas are needed.

Effect of changes in treatment practice on survival for cervical cancer: results from a population-based study in Manitoba, Canada

BACKGROUND

Results from clinical trials in the 1990s led to changes in the recommended treatment for the standard therapy for stage IIB-IVA cervical cancer from radiotherapy alone to chemo-radiotherapy. We conducted the first population-based study in Canada to investigate temporal treatment patterns for cervical cancer and long-term survival in relation to these changes in the treatment guidelines.

METHODS

Detailed information on stage and treatment for 1085 patients diagnosed with cervical cancer in 1984-2008 and identified from the population-based Manitoba Cancer Registry (MCR) in Canada was obtained from clinical chart review and the MCR. Factors associated with receiving guideline treatment were identified using logistic regression. All cause and cervical cancer specific survival were compared in patients who were and were not treated as recommended in the guidelines, using Cox proportional hazards models.

RESULTS

The median follow-up time was 6.4 years (range: 0.05-26.5 years). The proportion of women who received guideline treatment was 79 % (95 % confidence interval [CI]: 76-81 %). However, the likelihood of being treated according to the guidelines over time was modified by age (p < 0.0001) and tumour stage at diagnosis (p = 0.002). Women who were treated according to the guidelines after the change in recommended clinical practice (1999-2008) had a significantly lower risk of death from all causes and from cervical cancer. This was driven by lower mortality rates in cases with stage IIB-IVA tumours (all causes of death: hazard ratio [HR] = 0.60, 95 % CI: 0.43-0.82, p = 0.002; cervical cancer related death: HR = 0.64, 95 % CI: 0.44-0.93, p = 0.02).

CONCLUSIONS

The management of cervical cancer patients in Manitoba, Canada was in good agreement with treatment guidelines although reasons for departure from the guideline recommendations could not be examined further due to lack of data. Treatment of stage IIB-IVA cervical cancers with recommended concurrent chemo-radiotherapy, which is now standard practice, was associated with substantially increased survival, although the effect of changes in clinical practice including maintenance of haemoglobin levels on improved survival cannot be ruled out as a contributing factor.

Mammography rates for breast cancer screening: a comparison of First Nations women and all other women living in Manitoba, Canada, 1999-2008

Introduction

First Nations (FN) women historically have low rates of preventive care, including breast cancer screening. We describe the frequency of breast cancer screening among FN women living in Manitoba and all other Manitoba (AOM) women after the introduction of a provincial, organized breast screening program and explore how age, area of residence, and time period influenced breast cancer screening participation.

Methods

The federal Indian Registry was linked to 2 population-based, provincial data sources. A negative binomial model was used to compare breast cancer screening for FN women with screening for AOM women.

Results

From 1999 through 2008, 37% of FN and 59% of AOM women had a mammogram in the previous 2 years. Regardless of area of residence, FN women were less likely to have had a mammogram than AOM women (relative rate [RR] = 0.69 in the north, RR = 0.55 in the rural south, and RR = 0.53 in urban areas).

Conclusions

FN women living in Manitoba had lower mammography rates than AOM women. To ensure equity for all Manitoba women, strategies that encourage FN women to participate in breast cancer screening should be promoted.

Pap test use and cervical cancer incidence in First Nations women living in Manitoba

This study examined Papanicolaou (Pap) test utilization, Pap test results, and cervical cancer incidence among First Nations (FN) women living in Manitoba, Canada taking into account age group, time period, and area of residence. Six population-based data sources were linked at an individual level. Negative binomial regression was used to compare Pap test utilization and results between FN and all other Manitoba (AOM) women. Poisson regression was used to compare cervical cancer incidence. Among women younger than 25 years, FN were more likely than AOM women to have had a Pap test [rate ratio (RR) = 1.37, 95% confidence intervals (CI), 1.22-1.53, 18-19 year olds; RR = 1.17, 95% CI, 1.05-1.31, 20-24 year olds]. There was no difference in Pap test use for women 25 to 29 or 30 to 39 years. FN 40 years and older were less likely to have a Pap test than AOM women (RR = 0.84, 95% CI, 0.75-0.93, 40-49 years old; RR = 0.71, 95% CI, 0.63-0.79, 50-59 years old; RR = 0.59, 95% CI, 0.52-0.66, 60-69 years old). FN were more likely than AOM women to have a high (RR = 1.88, 95% CI, 1.65-2.13) or low-grade Pap test result (RR = 1.60, 95% CI, 1.48-1.73). The invasive cervical cancer incidence rate was double for FN women 25 to 39 years of age (21.9 per 100,000, FN; 10.2 per 100,000, AOM, P = 0.006) and 40 to 69 years of age (24.3 per 100,000, FN; 12.3 per 100,000, AOM, P = 0.007). In conclusion, cervical cancer screening among FN women over 40 years of age must be increased to address the higher cervical cancer incidence.

Colorectal cancer screening in first nations people living in Manitoba

BACKGROUND

Because the burden of colorectal cancer (CRC) seems to be increasing in First Nations, it is important to better understand CRC screening utilization. The objective of this study was to describe CRC screening among First Nations living in Manitoba.

METHODS

The Federal Indian Register was linked to two provincial databases. A negative binomial model was used to compare the probability of First Nations having a fecal occult blood test (FOBT), colonoscopy, or flexible sigmoidoscopy (FS) with all other Manitobans.

RESULTS

First Nations who lived in Winnipeg were significantly less likely to have had a FOBT in the previous 2 years than all other Manitobans who lived in Winnipeg [rate ratio (RR) = 0.40; 95% confidence intervals (CI), 0.37-0.44]. There was no difference in the likelihood of having a colonoscopy or FS for First Nations individuals who resided in northern Manitoba compared with all other Manitobans (RR, 1.04; 95% CI, 0.91-1.19). However, First Nations who lived in the rural south or urban areas were less likely than all other Manitobans to have had a colonoscopy or FS (RR, 0.81, 95% CI, 0.75-0.87, rural south; RR, 0.86, 95% CI, 0.81-0.92, urban).

CONCLUSIONS

First Nations living in Winnipeg were significantly less likely to be screened for CRC using the FOBT. Colonoscopy and FS use depended on area of residence.

IMPACT

First Nations experience barriers that impede the use of CRC screening. Further research is needed to understand these barriers to extend the benefit of CRC screening to this population. Cancer Epidemiol Biomarkers Prev; 24(1); 241-8. ©2014 AACR.

Effectiveness of the quadrivalent human papillomavirus vaccine against cervical dysplasia in Manitoba, Canada

PURPOSE

Effectiveness of the quadrivalent human papillomavirus (QHPV) vaccine against cervical dysplasia has not been estimated using population-based individual level data. We assessed the vaccine effectiveness (VE) of the QHPV vaccine against cervical dysplasia using data collected routinely in Manitoba.

METHODS

Females ≥ 15 years old who received the QHPV vaccine in Manitoba between September 2006 and April 2010 privately (n = 3,541) were matched on age to up to three nonvaccinated females (n = 9,594). We used Cox regression models to estimate the hazard ratios for three outcomes: atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesions (LSILs), and high-grade SILs (HSILs).

RESULTS

Among the 15- to 17-year-olds, the adjusted VE estimates were 35% (95% CI, -19% to 65%), 21% (-10% to 43%), and -1% (-44% to 29%) against the detection of HSILs, LSILs, and ASCUS, respectively. The corresponding estimates were higher (46% [0% to 71%], 35% [10% to 54%], and 23% [-8% to 45%]) among those who had ≥ one Pap smear after enrollment. The QHPV vaccine was associated with 23% (-17% to 48%) reduction in HSIL risk among those ≥ 18 with no history of abnormal cytology, but there was no evidence of protection among those with such a history (-8% [-59% to 27%]).

CONCLUSION

A significant percentage of vaccinated women may not be protected against HSIL and lesser dysplasia especially if they were vaccinated at older age (≥ 18) or had abnormal cytology before vaccination. These findings affirm the importance of vaccination before any significant exposure to HPV occurs and underscore the need for screening programs that cover all sexually active women, even if they were vaccinated.

Human papillomavirus vaccination and Pap testing profile in Manitoba, Canada

BACKGROUND

Females who receive the human papillomavirus (HPV) vaccine may believe they are protected from developing cervical cancer and no longer require screening. Concern has also been expressed that vaccinated females are those that would be screened regularly. This study assesses the Pap testing behavior of vaccinated and non-vaccinated females.

METHODS

For this population-based retrospective cohort study, vaccination and screening registries were linked for 3540 vaccinated females aged 15 years and over and 9592 matched non-vaccinated females. Conditional logistic regression, the Kaplan-Meier method and Cox regression were used to examine the association between vaccination and Pap testing.

RESULTS

Vaccinated females were more likely to have had a Pap test within the year prior to the index date than non-vaccinated females (15-19 years old: OR=1.38, 95% CI 1.20-1.59; 20+ years old: OR=2.34, 95% CI 1.98-2.76). In the three-year period after the index date, vaccinated females had a significantly higher cumulative probability of having a Pap test (83.3%) than non-vaccinated females (66.1%). Females who had a Pap test within three years prior to the index date were more likely to have a Pap test after the index date (vaccinated: HR=5.03, 95% CI 4.65-5.45; non-vaccinated HR=3.97, 95% CI 3.70-4.24). Being vaccinated had a significant effect on Pap testing (15-19 years old: HR=1.54, 95% CI 1.39-1.69; 20+ years old: HR=1.87, 95% CI 1.52-2.31). 80.1% of vaccinated females who had a Pap test prior to the index date also had one subsequent to it, compared to 70.1% for non-vaccinated females. 41.1% of females had not been vaccinated nor had a Pap test.

CONCLUSION

The majority of vaccinated females continue to participate in screening, and do so at a higher rate than non-vaccinated females. Renewed efforts need to be made to include the large proportion of non-vaccinated, non-screened females in vaccination and/or screening.

Type-specific prevalence of human papillomavirus in women screened for cervical cancer in Labrador, Canada

Background

A higher incidence of cervical cancer and human papillomavirus (HPV) infection has been reported in northern Canada and in First Nation, Métis and Inuit women, with some evidence to suggest that the HPV type distribution in these populations may be different from the rest of Canada.

Objective

The objective of this study was to measure the HPV type prevalence in Labrador women to determine if significant differences in HPV types could reduce the effectiveness of HPV vaccination.

Design

The prevalence of HPV types was determined in 1,370 women presenting for routine pap screening in Labrador between February and November 2010. Cervical cytology and HPV genotyping were performed on the same liquid-based cytology specimens.

Results

The overall prevalence of HPV was 21.4%; cytological abnormalities were found in 8.8% of the participants. HPV 16 and 18 were the most common high-risk HPV types. These two types were found in 52.4% of high-grade lesions. The prevalence in HPV infections was comparable across the Labrador regions.

Conclusions

The present results support the potential effectiveness of the HPV immunization program in Labrador.

Urothelial Cancer and the Diagnosis of Subsequent Malignancies

Purpose: We examine the likelihood of a second primary malignancy diagnosis following the diagnosis of urothelial cancer.Methods: We identified subjects from the Manitoba Cancer Registry diagnosed with urothelial cancer between April 1, 1985 and December 31, 2007. Data were collected on all subsequent new cancer diagnoses. Standardized incidence ratios (SIRs) were calculated for each major cancer type, matched with the general population by age, sex and period. Further analysis was undertaken stratifying by morphology and invasiveness. The results in males were examined with and without prostate cancer. A competing risk model was used to analyze the data controlling for death.Results: Of the 4412 included urothelial cancer cases, 712 patients (16.1%) subsequently developed a second primary malignancy. Risks were highest within 1 year of diagnosis persisting for 5 years. This risk was highest in males aged less than 70 (SIR = 6.25; 95% Confidence Interval [CI] 5.08-7.04). Overall, the risk was similarbetween the sexes (female SIR: 1.30, CI 1.09-1.54; males 1.42, CI1.31-1.54; males excluding prostate SIR: 1.22 CI 1.11-1.35). There was an increased relative risk for developing a second primary for cancers of the kidney (male), lung, breast (female) and prostate. Papillary cancers were associated with increased relative risk of developing lung, prostate, and breast (female and male) cancer.  In the competing risks model, patients diagnosed with a papillary or insitu urothelial cancer were more likely to be diagnosed with a second primary than non-papillary and invasive disease, respectively.Conclusions: Those diagnosed with urothelial cancer have an increased probability of having a second primary cancer detected within the subsequent 5 years, even when prostate cancer is excluded. Papillary tumours in particular may provide a warning for subsequent malignancy.

Distribution of human papillomavirus types, cervical cancer screening history, and risk factors for infection in Manitoba

OBJECTIVES

We conducted a study to investigate the prevalence of human papillomavirus (HPV) infections in an opportunistic sample of women in Manitoba, Canada. We inquired about risk factors associated with HPV infections and linked the HPV typing results with the cervical cancer screening history of the participants.

METHODS

The study population included 592 women attending Papanicolaou (Pap) test clinics. After signing a consent form, participants were given a self-administered questionnaire on risk factors and received a conventional Pap test. Residual cells from the Pap tests were collected and sent for HPV typing.

RESULTS

The mean age of the population was 43 years. A total of 115 participants (19.4%) had an HPV infection, 89 of whom had a normal Pap test. Of those who were HPV-positive, 61 (10.3%) had high-risk (Group 1) HPV. HPV-16 was the most prevalent type (15/115: 13.0% of infections). The most consistent risk factors for HPV infection were young age, Aboriginal ethnicity, higher lifetime number of sexual partners and higher number of sexual partners in the previous year.

CONCLUSION

The prevalence of HPV types in Manitoba is consistent with the distributions reported in other jurisdictions. These data provide baseline information on type-specific HPV prevalence in an unvaccinated population and can be useful in evaluating the effectiveness of the HPV immunization program. An added benefit is in the validation of a proof of concept which links a population-based Pap registry to laboratory test results and a risk behaviour survey to assess early and late outcomes of HPV infection. This methodology could be applied to other jurisdictions across Canada where such capacities exist.

Increased risk of nonmelanoma skin cancers among individuals with inflammatory bowel disease

BACKGROUND & AIMS

There are limited data on the risk of nonmelanoma skin cancer (NMSC) among individuals with inflammatory bowel disease (IBD), including those with or without exposure to immunosuppressant medications.

METHODS

Individuals with IBD (n = 9618) were identified from the University of Manitoba IBD Epidemiology Database and matched with randomly selected controls (n = 91,378) based on age, sex, and postal area of residence on the date of IBD diagnosis (index date). Groups were followed up from the index date until a diagnosis of any invasive cancer (including NMSC), death, migration from the province, or the end of the study (December 31, 2009), whichever came first. Cox regression analysis was performed to calculate the relative risk of NMSC among the individuals with IBD, adjusting for frequency of ambulatory care visits and socioeconomic status.

RESULTS

Of the individuals followed, 1696 were diagnosed with basal cell skin cancer (BCC) and 341 were diagnosed with squamous cell skin cancer (SCC). Individuals with IBD had an increased risk for BCC, compared with controls (hazard ratio, 1.20; 95% confidence interval [CI], 1.03-1.40). Among patients with IBD, use of thiopurines increased the risk of SCC (hazard ratio, 5.40; 95% CI, 2.00-14.56), compared with controls. Use of thiopurines also was associated with SCC in a case-control, nested analysis of individuals with IBD (odds ratio, 20.52; 95% CI, 2.42-173.81).

CONCLUSIONS

The risk of BCC could be increased among individuals with IBD. Use of thiopurines increases the risk of SCC among individuals with IBD.

The burden of cancer risk in Canada's indigenous population: a comparative study of known risks in a Canadian region

BACKGROUND

Canadian First Nations, the largest of the Aboriginal groups in Canada, have had lower cancer incidence and mortality rates than non-Aboriginal populations in the past. This pattern is changing with increased life expectancy, a growing population, and a poor social environment that influences risk behaviors, metabolic conditions, and disparities in screening uptake. These factors alone do not fully explain differences in cancer risk between populations, as genetic susceptibility and environmental factors also have significant influence. However, genetics and environment are difficult to modify. This study compared modifiable behavioral risk factors and metabolic-associated conditions for men and women, and cancer screening practices of women, between First Nations living on-reserve and a non-First Nations Manitoba rural population (Canada).

METHODS

The study used data from the Canadian Community Health Survey and the Manitoba First Nations Regional Longitudinal Health Survey to examine smoking, binge drinking, metabolic conditions, physical activity, fruit/vegetable consumption, and cancer-screening practices.

RESULTS

First Nations on-reserve had significantly higher rates of smoking (P < 0.001), binge drinking (P < 0.001), obesity (P < 0.001) and diabetes (P < 0.001), and less leisure-time physical activity (P = 0.029), and consumption of fruits and vegetables (P < 0.001). Sex differences were also apparent. In addition, First Nations women reported significantly less uptake of mammography screening (P < 0.001) but similar rates for cervical cancer screening.

CONCLUSIONS

Based on the findings of this retrospective study, the future cancer burden is expected to be high in the First Nations on-reserve population. Interventions, utilizing existing and new health and social authorities, and long-term institutional partnerships, are required to combat cancer risk disparities, while governments address economic disparities.

Screening for cervical and breast cancer among women with inflammatory bowel disease: a population-based study

BACKGROUND

There are limited data on rates and predictors of cervical and/or breast cancer screening among women with inflammatory bowel disease (IBD). Immunosuppressant medications used to manage IBD may increase the risk of cervical cancer precursor lesions.

METHODS

Women diagnosed with IBD prior to 2002 were matched to up to 10 Manitoba residents without the disease. Logistic regression analyses were performed to compare utilization of Papanicolaou (Pap) tests and mammograms in the two groups. Among women with IBD, we analyzed the differences in screening between those with and without exposure to immunosuppressant medications and/or corticosteroids and effect of age, socioeconomic status, prior diagnostic testing, and intensity of healthcare utilization.

RESULTS

In all, 54% of the 2344 women with IBD and 52% of the 15,333 controls had regular Pap tests between 2002 and 2008. In multivariate analyses, older age, lower socioeconomic status, lower intensity of healthcare utilization, Crohn's disease, and exposure to immunosuppressant medications were independent predictors of lower use of Pap testing. Although there were no significant differences in the use of mammograms in women with or without IBD or among women with IBD with or without exposure to immunosuppressant medications, only 47% of women with IBD in the target age group had mammograms regularly.

CONCLUSIONS

Despite a need for higher testing, women with IBD on immunosuppressant medications are less likely to undergo Pap testing. Healthcare providers involved in the care of women with IBD need to remind these individuals about regular preventive care.

The reduction in colorectal cancer mortality after colonoscopy varies by site of the cancer

BACKGROUND & AIMS

There are limited data on mortality from colorectal cancer (CRC) among patients who have received colonoscopy examinations. We sought to determine CRC mortality among persons undergoing colonoscopies compared with the general population.

METHODS

We identified all individuals who had a colonoscopy as their first lower gastrointestinal endoscopy from April 1, 1987, to September 30, 2007 (24,342 men and 30,461 women), based on information from Manitoba's provincial physicians' billing claims database. Patients were followed until March 31, 2008, death, or migration out of the province (310,718 person-years). Individuals less than 50 years of age or more than 80 years of age at the index colonoscopy or those with prior sigmoidoscopy, inflammatory bowel disease, resective colorectal surgery, or CRC were excluded. CRC mortality after the index colonoscopy was compared with that of the general population by standardized mortality ratios (SMRs). Stratified analyses were performed to determine CRC mortality for different age groups at index colonoscopy and sex, duration of follow-up, medical specialty of the endoscopist, and site of CRC.

RESULTS

There was a 29% reduction in overall CRC mortality (SMR, 0.71; 95% confidence interval [CI], 0.61-0.82], a 47% reduction in mortality from distal CRC (SMR, 0.53; 95% CI, 0.42-0.67), and no reduction in mortality from proximal CRC (SMR, 0.94; 95% CI, 0.77-1.17). The reduction in mortality from distal CRC remained significant for follow-up beyond 10 years (SMR, 0.53; 95% CI, 0.31-0.84).

CONCLUSIONS

In Manitoba, colonoscopies significantly reduce mortality from CRC, but the benefit is not uniform for colorectal tumors that arise in different areas of the colon.

Analysis of wait times and costs during the peri-diagnostic period for non-small cell lung cancer

PURPOSE

To determine the wait times and healthcare costs around the time of non-small cell lung cancer (NSCLC) diagnosis for a large, population-based cohort of patients.

METHODS

Data on baseline demographics, diagnostic and staging tests, timelines of investigations, and frequency of physician visits and hospital admissions were obtained from a provincial cancer registry and health administrative databases for 2852 patients, who were diagnosed with NSCLC from 1996 to 2000 in Manitoba, Canada. Dates between investigations were used to determine wait times surrounding diagnosis and fee codes for physician and hospital services were used to estimate costs.

RESULTS

The median wait times from chest x-ray to chest computed tomography (CT) scan and from CT scan to definitive histological diagnosis were 8 (inter-quartile range 1-25) and 18 (inter-quartile range 3-42) days, respectively. At least 25% of patients waited more than 55 days from initial suspicion on chest x-ray to final diagnosis of NSCLC. The mean cost per case of NSCLC diagnosis was $6,978 (in Canadian dollars) where the majority of expenses was attributed to hospital admissions and repeated physician visits before a diagnosis was confirmed.

CONCLUSIONS

Despite clinical suspicion for NSCLC, a significant number of patients wait more than 8 weeks for a definitive diagnosis. Substantial costs are incurred by the Canadian universal healthcare system in the months surrounding diagnosis. Establishment of more efficient and cost-effective healthcare delivery in the peri-diagnostic time period may benefit the system as well as the patients.

The Manitoba human papillomavirus vaccine surveillance and evaluation system

BACKGROUND

With the recent introduction of a human papillomavirus (HPV) vaccine in Canada, it is important to establish surveillance and evaluation programs that not only track the uptake of the vaccine, but also assess its safety and its impact on: distribution of HPV type, cervical cancer screening programs, the incidence of anogenital warts, precancerous lesions and various cancers, and sexual behaviour.

DATA SOURCES AND METHODS

Administrative databases, registries and questionnaire information are being linked to identify people receiving the HPV vaccine and to develop an evaluation system.

INTERPRETATION

The availability of extensive linkable databases in Manitoba allows for the development of a comprehensive HPV vaccine surveillance and evaluation system that can address many of the questions related to the HPV vaccine. Aspects of the Manitoba surveillance and evaluation system could be implemented in other provinces that have similar databases.

Predictors of colorectal cancer after negative colonoscopy: a population-based study

OBJECTIVES

A higher proportion of colorectal neoplasia among women occurs in the proximal colon, which might be more frequently missed by colonoscopy. There are no data on predictors of developing colorectal cancer (CRC) after a negative colonoscopy in usual clinical practice. We evaluated gender differences and predictors of CRC occurring after a negative colonoscopy.

METHODS

All individuals 40 years or older with negative colonoscopy were identified from Manitoba's provincial physicians' billing claims database. Individuals with less than 5 years of coverage by the provincial health plan, earlier CRC, inflammatory bowel disease, resective colorectal surgery, or lower gastrointestinal endoscopy were excluded. CRC risk after negative colonoscopy was compared to that in the general population by standardized incidence ratios. Cox regression analysis was performed to determine the independent predictors of CRC occurring after negative colonoscopy.

RESULTS

A total of 45,985 individuals (18,606 men; 27,379 women) were followed up for 229,090 person-years. After a negative colonoscopy, men had a 40-50% lower risk of CRC diagnosis through most of the follow-up time. Risk among women was similar to that of women in the general population in the first 3 years and then was 40-50% lower. Older subject age and performance of index colonoscopy by non-gastroenterologists were independent predictors for early/missed CRC (cancers occurring within 3 years of negative colonoscopy).

CONCLUSIONS

Women may have a higher rate of missed/early CRCs after negative colonoscopy. Predictors of missed/early CRCs after negative colonoscopy include older age and performance of index colonoscopy by a non-gastroenterologist.

Population-based patterns and cost of management of metastatic non-small cell lung cancer after completion of chemotherapy until death

BACKGROUND

The aim of this study was to examine the patterns and costs of management of non-small cell lung cancer (NSCLC) after completion of chemotherapy until death in a population of patients in Manitoba, Canada.

PATIENTS AND METHODS

Stage IIIB and IV NSCLC patients diagnosed between January 1997 and June 2000 who received chemotherapy as the primary treatment, completed their chemotherapy and survived for at least 28 days since their last treatment, and were on best supportive care (BSC) were selected. Treatment, services received, costs, and survival were determined by chart review and examining various databases including the Manitoba Cancer Registry, medical claims, hospitalizations, and prescription drugs. Costs of treatment, average cost per patient, and lifetime treatment costs were calculated.

RESULTS

Of the 2463 patients diagnosed with NSCLC over the study period, 150 patients matched our study criteria. From the beginning of the first chemotherapy treatment, the median survival time was 31.8 weeks, while from the date of BSC the median survival time was 13.8 weeks. The average cost per case was $10,805 from last date of chemotherapy and $8654 during the BSC period. The average cost per patient-month ranged from $1645 to $1792 in current prices. Lifetime treatment costs ranged from $8702 to $11,057. Hospitalizations accounted for 80% of the total treatment costs.

CONCLUSION

The largest overall component of cost after the end of chemotherapy was hospitalizations. Effective new therapies that reduce the episodes of hospitalizations would have a significant impact on decreasing aggregate costs.

Long-term use of statins and risk of colorectal cancer: a population-based study

OBJECTIVES

We conducted a population-based cohort study to determine the effect of long-term regular use of statins on the risk of colorectal cancer (CRC).

METHODS

Individuals who were dispensed statins regularly were identified from Manitoba's population-based prescription drug database and followed up until diagnosis of CRC, migration out of province, death, or December 2005. The incidence of CRC in this group was compared with that among individuals who were never dispensed statins. Stratified analysis was performed to determine the risk after 5 years of regular statin use. Multivariate Poisson regression models were used to adjust for potential confounding by age, sex, and history of diabetes, inflammatory bowel disease, coronary heart disease, lower gastrointestinal endoscopy, resective colorectal surgery, use of nonsteroidal anti-inflammatory drugs, hormone replacement therapy (among women), and median household income. The dose effect was evaluated in defined daily dose units.

RESULTS

In total, 35,739 individuals were dispensed statins regularly. In all, 10,287 (49% males; 51% females) long-term (>or=5 years) regular statin users were followed up for up to 5 additional years. In multivariate analysis, the incidence rate ratio (IRR) of CRC among those dispensed statins regularly compared with those who were never dispensed statins (n=377,532) was 1.13 (95% confidence interval (CI): 1.02-1.25). The CRC risk among the long-term regular statin users was similar to that for individuals never dispensed statins (IRR, 0.89; 95% CI: 0.70-1.13). A statistically nonsignificant risk reduction was observed among high-dose long-term regular statin users.

CONCLUSIONS

These findings suggest that long-term regular use of statins for the current clinical indications does not protect against CRC. The benefit of high-dose long-term statin use needs further evaluation.

Incidence and anatomic presentation of cutaneous malignant melanoma in central Canada during a 50-year period: 1956 to 2005

BACKGROUND

Incidence rates of cutaneous malignant melanoma (CMM) have increased worldwide. Long-term studies examining rates and anatomic site-specific incidence on a population-based level are infrequent.

OBJECTIVE

We sought to examine the historical changes in the incidence and anatomic site presentation of CMM during a 50-year period in Manitoba, Canada.

METHODS

Using population-based data, all first diagnoses of CMM reported between 1956 and 2005 were identified. Age-specific rates, age-standardized incidence rates, and anatomic sites were recorded.

RESULTS

Incidence rates of CMM slowed for each sex beginning in 1981 for female patients and 1992 for male patients. Annual percent change revealed decreasing rates among male patients younger than 40 years (1992-2005: -5.3% [P = .03]) and female patients younger than 40 years (1987-2005: -1.8% [P = .15]). Similarly, middle-aged individuals (age 40-59 years) also had diminished annual percent change (men 1992-2005: 0.6% [P = .65]; women 1983-2005: -0.3% [P = .68]). The annual percent change for older men and women (60-79 and > or =80 years) continued to increase. Anatomic site-specific analyses revealed that the trunk was the most frequent site of CMM for young male patients (<60 years) whereas the lower extremities were the most common among young female patients (<60 years). Incidence rates for each site, however, are slowing. Among those aged 60 years and older, the rates for each anatomic site increased.

LIMITATIONS

Determining changes in tumor thickness would have been useful in determining whether the nature of tumors have changed over time; however, this is not recorded in our registry.

CONCLUSION

The rates of CMM are slowing; however, this change is confined to younger individuals. Anatomic site-specific CMMs are changing; rates among older individuals continue to increase for both sexes.

Risk of cervical abnormalities in women with inflammatory bowel disease: a population-based nested case-control study

BACKGROUND & AIMS

We evaluated the risk of cervical abnormalities in women with inflammatory bowel disease (IBD) in a population-based, nested, case-control study.

METHODS

Cases with abnormal Papanicolaou (Pap) smears or cervical biopsies were matched with up to 3 controls (normal Pap smears) by year of birth, year of first health care coverage, and number of Pap smears in the preceding 5 years. A diagnosis of IBD before the index date was identified from the University of Manitoba IBD Epidemiology Database. Exposures to immunosuppressant drugs and corticosteroids were determined from the provincial drug prescription database. Analyses were adjusted for socioeconomic status and exposure to oral contraceptives and nonsteroidal anti-inflammatory drugs.

RESULTS

19,692 women with cervical cytologic and/or histologic abnormalities were matched with 57,898 controls with normal Pap smears. There was no association between cervical abnormalities and ulcerative colitis (odds ratio [OR], 1.03; 95% confidence interval [CI], 0.77-1.38). The increase in risk in women with Crohn's disease was limited to those exposed to 10 or more prescriptions of oral contraceptives (OR, 1.66; 95% CI, 1.08-2.54). The combined exposure to corticosteroids and immunosuppressants was associated with increased risk of cervical abnormalities (OR, 1.41; 95% CI, 1.09-1.81). There was no interaction between the effect of IBD and corticosteroids and/or immunosuppressants.

CONCLUSIONS

These findings do not support an association between IBD itself and the risk of developing cervical abnormalities. An increased risk in patients given a combination of corticosteroids and immunosuppressants should be considered in managing women with IBD.

Time trends in colon cancer incidence and distribution and lower gastrointestinal endoscopy utilization in Manitoba

OBJECTIVES

There are limited data on recent trends in subsite-specific colon cancer incidence and utilization of lower gastrointestinal endoscopy from Canada. The aim of our study was to determine the concomitant trends in right-sided colon cancer incidence and utilization of colonoscopy and flexible sigmoidoscopy (FS) in Manitoba.

METHODS

Cases of colon cancer diagnosed from 1964 to 2004 were identified from the Manitoba Cancer Registry. Lower gastrointestinal endoscopies performed between 1984 and 2003 were identified from Manitoba Health's Physician Claims database. Trends of age-standardized incidence rates were determined using Joinpoint analyses.

RESULTS

Rates of right-sided colon cancer showed a monotonic increase in both sexes (annual percent change [APC] in both sexes 1.04%, P < 0.001). The most rapid increase (200%) occurred in individuals of 70 yr of age and older. While rates of colonoscopies without polypectomies quadrupled between 1985 (257 per 100,000) and 2003 (1,083 per 100,000, APC 8.89%, P < 0.001), rates of colonoscopies with polypectomies quadrupled from 35 per 100,000 in 1985 to 140 per 100,000 in 2000, and then increased more rapidly in the subsequent 4 yr (233 per 100,000 in 2003, APC 20%, P < 0.001). Rates of FS declined between 1999 (342 per 100,000) and 2003 (257 per 100,000, APC -6.68%, P= 0.01).

CONCLUSIONS

The rates of right-sided colon cancer are continuing to increase in Manitoba, with the most rapid increase occurring in older individuals. Reasons for the increasing incidence of right-sided colon cancer despite increasing rates of colonoscopy need to be further explored, and may reflect increased detection of asymptomatic cancers or a real increase in right-sided colon cancer incidence.

High rate of discordance between clinical and autopsy diagnoses in blood and marrow transplantation

We analyzed autopsies performed in a Canadian blood and marrow transplantation (BMT) program. We aimed to assess variables that predict the performance of an autopsy, whether rates of autopsy are changing, and the rate of discordance between clinical and autopsy diagnoses. All deceased adult patients from January 1990 to December 2004 were reviewed. Autopsy rates were compared to a large teaching hospital. Of 476 myeloablative BMT patients, 225 died and 48 (27%) underwent autopsy. Autopsy was more likely in patients dying: <100 days post-BMT, in the intensive care unit, after allografting, and on weekends. Autopsy rates among BMT patients declined during the three time periods (1990-1994, 1995-1999, 2000-2004). The autopsy rate at the teaching hospital showed a similar downward temporal trend. Major and minor disagreements at autopsy were present in 16 (34%) and 14 (30%) of cases, respectively. There was no change in discordance rates over time. Thus, despite advances in diagnostic procedures, high levels of disagreement between clinical and autopsy diagnoses for BMT patients persist as autopsy rates decline. We recommend that the autopsy regains its role as a valuable investigation. This may become especially relevant in an era where patients with medical comorbidities are undergoing reduced-intensity BMT.

Trends in cancer prevalence in Quebec

Cancer prevalence is of prime interest in public health because of its use in estimating the disease's burden on the heath care system. This study's objective was to estimate five-year prevalence of tumours from 1989 to 1999 and ten-year prevalence of tumours from 1994 to 1999 in the Province of Quebec (Canada). Five-year prevalence was used to represent tumours for which people are more likely to obtain primary treatment; ten-year prevalence included those tumours in addition to tumours that can be considered cured but still need follow-up. Information was extracted from the Quebec Cancer Registry. Prostate cancer was the most prevalent malignancy among males (25 percent, five-year prevalent tumours), while breast cancer was most prevalent among females (38 percent, five-year prevalent tumours). For both sexes, the greatest observed prevalence increase was for endocrine glands. On average, five-year prevalence proportions were 16 percent higher in men than in women; those of ten year were 14 percent higher in men. Furthermore, the largest differences were observed for bladder and lung cancer. The change in cancer prevalence in Quebec was dependent on the tumour site.

Risk of Second Primary Cancer and Death Following a Diagnosis of Nonmelanoma Skin Cancer

Cancer-free patients diagnosed with a first primary nonmelanoma skin cancer (NMSC) offer an opportunity for studying the risk of a second primary cancer without the confounding effect of systemic treatment. The objective of the study was to estimate the risk of second primary cancer in people with a history of basal cell carcinoma (BCC) or squamous cell carcinoma (SCC) and the risk of dying in cancer patients with a NMSC history. BCC and SCC cases diagnosed between 1956 and 2000 in Manitoba, Canada were followed-up for second primaries (other than NMSC). Standardized incidence and mortality ratios (SIR and SMR) were calculated. Men [SIR, 1.06; 95% confidence interval (95% CI), 1.02-1.10] and women (SIR, 1.07; 95% CI, 1.02-1.12) with a BCC history as well as men (SIR, 1.15; 95% CI, 1.08-1.22) with a SCC history were at greater risk of a second primary cancer. Overall, the increased risk was observed only in the first 4 years following a NMSC, although it remained increased for specific cancer sites. The risk remained higher in all age groups up to 75 years of age. People with a history of BCC (males: SMR, 1.09; 95% CI, 1.04-1.14; females: SMR, 1.24; 95% CI, 1.16-1.32) or SCC (males: SMR, 1.18; 95% CI, 1.09-1.27; females: SMR, 1.55; 95% CI, 1.35-1.79) had a greater risk of death following their second primaries. Even if NMSC patients are at greater risk of a second cancer, it is not recommended to follow them up beyond the generally accepted periodic examination of the skin.

Trends of nonmelanoma skin cancer from 1960 through 2000 in a Canadian population

Nonmelanoma skin cancer (NMSC) is the most common malignancy diagnosed in Caucasian populations, but little is known about its occurrence in Canada. We sought to determine the historical change of the occurrence and risk of NMSC. All first diagnoses of NMSC reported in Manitoba between 1960 and 2000 were identified. Rates were reported as well as lifetime risk of developing the disease. Basal cell carcinoma was the predominant form of NMSC, accounting for 79% of all NMSCs. The annual percentage change of basal cell and squamous cell carcinoma increased 2.4%, mainly in people older than 40 years of age from the early 1970s to 2000. The lifetime risk of being diagnosed with NMSC increased by two to three times in the 1990s compared to the 1960s. We concluded that because of the potentially high impact of NMSC on resource utilization and treatment-related costs as well as its easily preventable character, priority should be given to prophylactic measures.

Breast cancer trends in Manitoba: 40 years of follow-up

This study reports a comprehensive array of breast cancer statistics for Manitoba for a 40-year period. Data from the Manitoba Cancer Registry were combined with the provincial population-based registration file to determine trends in breast cancer incidence, prevalence and mortality rates, as well as survival and the probability of being diagnosed with breast cancer in the next 10 years. The age-standardized incidence rate of breast cancer increased by 0.99/100,000 women per year over the 40 years of follow-up (69.6/100,000 women in 1960, 109.9/100,000 women in 1999). Mortality rates peaked in 1986 (35.7/100,000 women), while the 1999 mortality rate (26.0/100,000 women) was almost comparable to the 1960 rate (22.4/100,000 women). No significant trend in mortality rate was observed over the 40-year period. The 5-year prevalence rate of breast cancer increased by 8.6/100,000 women per year. Between 1960-64 and 1995-99, 5-year survival increased from 0.62 to 0.86. The probability of being diagnosed with breast cancer in the next 10 years increased the most for women 60 years of age. The breast cancer burden in Manitoba is rapidly evolving mainly because of the increasing incidence and the better survival of cases. Key words: breast neoplasms, incidence, prevalence, registries, vital statistics.