Projected estimates of cancer in Canada in 2024.

BACKGROUND: Cancer surveillance data are essential to help understand where gaps exist and progress is being made in cancer control. We sought to summarize the expected impact of cancer in Canada in 2024, with projections of new cancer cases and deaths from cancer by sex and province or territory for all ages combined. METHODS: We obtained data on new cancer cases (i.e., incidence, 1984-2019) and deaths from cancer (i.e., mortality, 1984-2020) from the Canadian Cancer Registry and Canadian Vital Statistics Death Database, respectively. We projected cancer incidence and mortality counts and rates to 2024 for 23 types of cancer, overall, by sex, and by province or territory. We calculated age-standardized rates using data from the 2011 Canadian standard population. RESULTS: In 2024, the number of new cancer cases and deaths from cancer are expected to reach 247 100 and 88 100, respectively. The age-standardized incidence rate (ASIR) and mortality rate (ASMR) are projected to decrease slightly from previous years for both males and females, with higher rates among males (ASIR 562.2 per 100 000 and ASMR 209.6 per 100 000 among males; ASIR 495.9 per 100 000 and ASMR 152.8 per 100 000 among females). The ASIRs and ASMRs of several common cancers are projected to continue to decrease (i.e., lung, colorectal, and prostate cancer), while those of several others are projected to increase (i.e., liver and intrahepatic bile duct cancer, kidney cancer, melanoma, and non-Hodgkin lymphoma). INTERPRETATION: Although the overall incidence of cancer and associated mortality are declining, new cases and deaths in Canada are expected to increase in 2024, largely because of the growing and aging population. Efforts in prevention, screening, and treatment have reduced the impact of some cancers, but these short-term projections highlight the potential effect of cancer on people and health care systems in Canada.

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. / Le point sur les tendances de l'incidence du cancer au Canada (1984-2017).

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.

Overall, cancer incidence is declining at a rate of −1.1% per year. In males, the two largest decreases were for prostate (−4.4% per year) and colorectal (−4.3% per year) cancer. In females, they were for thyroid (−5.4% per year) and colorectal (−3.4% per year) cancer. Melanoma (males: 2.2% per year; females: 2.0% per year) and multiple myeloma (males: 2.5% per year; females: 1.6% per year) rates are increasing. Cancer trends in Canada are dynamic and type-specific. The decreases for prostate and thyroid cancer underscore the importance of updating testing practices based on best evidence.

Dans l'ensemble, l'incidence du cancer diminue à un taux de −1,1 % par année. Les deux plus fortes baisses ont été observées chez les hommes pour le cancer de la prostate (−4,4 % par année) et le cancer colorectal (−4,3 % par année) et, chez les femmes, pour le cancer de la thyroïde (−5,4 % par année) et le cancer colorectal (−3,4 % par année). Les taux de mélanome sont en hausse (hommes : 2,2 % par année; femmes : 2,0 % par année) ainsi que ceux de myélome multiple (hommes : 2,5 % par année; femmes : 1,6 % par année). Les tendances en matière de cancer au Canada sont dynamiques et elles dépendent de chaque type de cancer. La diminution de l'incidence du cancer de la prostate et du cancer de la thyroïde souligne l'importance de mettre à jour les pratiques de dépistage à partir des meilleures données probantes.

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.

Continued increasing incidence of malignant appendiceal tumors in Canada and the United States: A population-based study.

BACKGROUND: To the authors' knowledge, there are limited data regarding the epidemiology of malignant appendiceal tumors. It remains unknown whether the previously reported trends are occurring in different countries and/or continuing in recent years and/or whether they are possibly due to increasing rates of appendectomies. In the current study, the authors investigated the patterns and time trends of malignant appendiceal tumor diagnosis by age group, sex, stage of disease, and histology in Canada and the United States and concomitant rates of appendectomies in Canada. METHODS: The Canadian Cancer Registry and the US Surveillance, Epidemiology, and End Results incidence databases were used to identify incident patients of malignant appendiceal tumors in the 2 countries between 1992 and 2016. The Canadian national hospitals Discharge Abstract Database was used to identify appendectomies performed between 2004 and 2015. Joinpoint regression analyses were performed to determine time trends. RESULTS: There was an overall increase in the incidence of malignant appendiceal tumors of 232% in the United States and 292% in Canada between 2000 and 2016. The increase was noted for malignant adenocarcinomas and neuroendocrine appendiceal tumors in both countries. The increase occurred across all age groups, sexes, and stages of disease. The highest rate of increase was noted for appendiceal neuroendocrine malignant tumors diagnosed among the youngest age groups. The rate of appendectomies was stable in the recent time periods, resulting in a decreasing rate of appendectomies per malignant appendiceal tumor diagnosis. CONCLUSIONS: The incidence of malignant appendiceal tumor is continuing to increase, which is not likely due to the increasing diagnosis of asymptomatic tumors at the time of appendectomies.

At-a-glance - Cancer trends in Canada, 1984 to 2015. / Aperçu - Tendances en matière de cancer au Canada, 1984-2015.

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).

The incidence of some cancers is changing rapidly in Canada. Recent trends show increasing rates of thyroid cancer in males, drawing attention to the potential impact of overdiagnosis. Prostate cancer incidence is decreasing rapidly, likely reflecting recent changes in screening guidelines.

Les tendances liées à l'incidence de certains cancers évoluent rapidement au Canada. Les tendances récentes révèlent une augmentation des taux d'incidence de cancer de la glande thyroïde chez les hommes, ce qui incite à étudier les répercussions potentielles de surdiagnostic. L'incidence du cancer de la prostate connaît une diminution rapide, ce qui témoigne vraisemblablement des changements récents apportés aux lignes directrices en matière de dépistage.

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.

Longitudinal Rates of Colon Cancer Screening Use in Winnipeg, Canada: The Experience of a Universal Health-Care System with an Organized Colon Screening Program.

OBJECTIVES: We examined trends in colorectal cancer (CRC) screening (fecal occult blood test (FOBT), colonoscopy, and flexible sigmoidoscopy (FS)) and differences in CRC screening by income in a population with an organized CRC screening program and universal health-care coverage. METHODS: Individuals who had an FOBT, colonoscopy, or FS were identified from the provincial Physician Claims database and the population-based colon cancer screening registry. Trends in age-standardized rates were determined. Logistic regression was performed to explore the association between CRC screening and income quintiles by year. RESULTS: Up-to-date CRC screening (FOBT, colonoscopy, or FS) increased over time for men and women, all age groups, and all income quintiles. Up-to-date CRC screening was very high among 65- to 69- and 70- to 74-year-olds (70% and 73%, respectively). There was a shift toward the use of an FOBT for CRC screening for individuals in the lower income quintiles. The disparity in colonoscopy/FS coverage by income quintile was greater in 2012 than in 1995. Overall, there was no reduction in disparities by income in up-to-date CRC screening nor did the rate of increase in up-to-date CRC screening or FOBT use change after the introduction of the organized provincial CRC screening program. CONCLUSIONS: CRC screening is increasing over time for both men and women and all age groups. However, a disparity in up-to-date CRC screening by income persisted even with an organized CRC screening program in a universal health-care setting.

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.

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.

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.

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.

Evaluating the effectiveness of cervical cancer screening invitation letters.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of an invitation letter on cervical screening participation among unscreened women 30 to 69 years of age. METHODS: A cluster randomized trial design was used in which unscreened women (n=31,452) were randomized by the forward sortation area (FSA) of their postal code to an intervention group that was sent an invitation letter (n=17,068) or a group that was not sent an invitation letter (n=14,384). RESULTS: Six months after the letters were mailed, 1,010 women in the intervention group (5.92%) and 441 women in the control group (3.06%) had a Pap test. After adjusting for variables that have previously shown to influence screening participation, women who were sent an invitation letter were significantly more likely to have had a Pap test in the next 6 months compared with women who were not sent an invitation letter (odds ratio [OR]=2.60, 95% confidence interval [CI] 2.09-3.35, p<0.001). Overall, the effectiveness of the invitation letter improved with increasing age (p=0.02). CONCLUSIONS: Sending invitation letters increased cervical screening participation but because the overall effect was small, additional strategies that remove barriers to screening for unscreened women are also necessary.

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 similar between the sexes (female SIR: 1.30, CI 1.09-1.54; males 1.42, CI 1.31-1.54; 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 in situ 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.

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.