Participation in the national cervical screening programme among women from New South Wales, Australia, by place of birth and time since immigration: A data linkage analysis using the 45 and up study.

OBJECTIVE: Equitable elimination of cervical cancer in Australia within the next decade will require high National Cervical Screening Program (NCSP) participation by all subgroups of women. The aim of this study was to examine the participation of immigrants compared to Australian-born women. METHODS: Participation in the NCSP (≥1cytology test) over a 3-year (2010-2012) and 5-year (2008-2012) period, by place of birth and time since immigration was examined using individually linked data of 67,350 New South Wales (NSW) women aged ≥45 enrolled in the 45 and Up Study. RESULTS: Three-year cervical screening participation was 77.0% overall. Compared to Australian-born women (77.8%), 3-year participation was lower for women born in New Zealand (adjusted odds ratio 0.77, 95% confidence interval 0.69-0.87), Oceania (0.67, 0.51-0.89), Middle East/North Africa (0.76, 0.60-0.97), South-East Asia (0.72, 0.60-0.87), Chinese Asia (0.82, 0.69-0.97), Japan/South Korea (0.68, 0.50-0.94), and Southern/Central Asia (0.54, 0.43-0.67), but higher for women from Malta (2.85, 1.77-4.58) and South America (1.33, 1.01-1.75). Non-English-speaking-at-home women were less likely to be screened than English-speaking-at-home women (0.85, 0.78-0.93). Participation increased with years lived in Australia but remained lower in immigrant groups compared to Australian-born women, even after ≥20 years living in Australia. Similar results were observed for 5-year participation. CONCLUSIONS: Women born in New Zealand, Oceania, and parts of Asia and the Middle East had lower NCSP participation, which persisted for ≥20 years post-immigration. The NCSP transition to primary HPV screening, and the introduction of the universal self-collection option in 2022, will offer new opportunities for increasing screening participation for these groups.

Incidence profile of four major cancers among migrants in Australia, 2005-2014.

PURPOSE: To compare the incidence profile of four major cancers in Australia by place of birth. METHODS: In this retrospective population-based cohort study, the analysis included 548,851 residents diagnosed with primary colorectum, lung, female breast, or prostate cancer during 2005-2014. Incidence rate ratio (IRR) and 95% confidence intervals (CI) were calculated for migrant groups relative to Australian-born. RESULTS: Compared with Australian-born residents, most migrant groups had significantly lower incidence rates for cancers of the colorectum, breast and prostate. The lowest rates of colorectal cancer were among males born in Central America (IRR = 0.46, 95% CI 0.29-0.74) and females born in Central Asia (IRR = 0.38, 95% CI 0.23-0.64). Males born in North-East Asia had the lowest rates of prostate cancer (IRR = 0.40, 95% CI 0.38-0.43) and females born in Central Asia had the lowest rates of breast cancer (IRR = 0.55, 95% CI 0.43-0.70). For lung cancer, several migrant groups had higher rates than Australian-born residents, with the highest rates among those from Melanesia (males IRR = 1.39, 95% CI 1.10-1.76; females IRR = 1.40, 95% CI 1.10-1.78). CONCLUSIONS: This study describes cancer patterns among Australian migrants, which are potentially helpful in understanding the etiology of these cancers and guiding the implementation of culturally sensitive and safe prevention measures. The lower incidence rates observed for most migrant groups may be maintained with continued emphasis on supporting communities to minimize modifiable risk factors such as smoking and alcohol consumption and participation in organized cancer screening programmes. Additionally, culturally sensitive tobacco control measures should be targeted to migrant communities with high lung cancer incidence rates.

Stage-Specific Risk of Breast Cancer among Canadian Immigrant and Non-Immigrant Women.

BACKGROUND: Breast cancer screening utilization varies across immigrant and non-immigrant populations. Recent studies have also suggested that some immigrant populations in Canada present with a higher frequency of later-stage breast cancer compared to non-immigrants. Our study aimed to augment prior research by presenting breast cancer stage distributions and stage-specific breast cancer incidence rates for immigrant and non-immigrants in British Columbia, Canada. METHODS: We utilized a population-based cohort of more than 1.3 million women built from linked administrative health and immigration data sets. Age-standardized incidence rate ratios were generated to compare immigrant and non-immigrant groups. Poisson regression was used to assess the relative frequency of later stage diagnosis among immigrant groups compared to non-immigrants. RESULTS: Indian and Chinese immigrants both showed significantly lower stage I and stage II-IV incidence rates compared to non-immigrants. However, Indian immigrants showed a higher frequency of later stage tumours at diagnosis compared to non-immigrants, while in contrast Chinese immigrants showed a lower frequency of later stage tumours. Filipino immigrants showed similar stage-specific rates and stage at diagnosis compared to non-immigrants. CONCLUSIONS: Our findings highlight a need for continued surveillance of cancer among immigrant and non-immigrant populations and inquiry into reasons for differences in stage at diagnosis across groups.

Incidence of anogenital warts after the introduction of the quadrivalent HPV vaccine program in Manitoba, Canada.

BACKGROUND: The incidence of anogenital warts (AGW) decreased after the introduction of the quadrivalent human papillomavirus (qHPV) vaccine in multiple jurisdictions. We studied how comparing AGW incidence rates with different outcomes affects the interpretation of the qHPV vaccination program. To do this, we replicated multiple study designs within a single jurisdiction (Manitoba). METHODS: We measured the incidence rates of AGW, AGW-related prescriptions, chlamydia, and gonorrhea (the latter two as sham outcomes) between 2001 and 2017 using several clinical and administrative health databases from Manitoba. We then used incidence rate ratios (IRRs) to compare, for each outcome, the rate for the 1997-1998 birth cohort (the first cohorts eligible for the publicly funded qHPV vaccination program) and the older 1995-1996 birth cohort. RESULTS: AGW incidence in Manitoba dropped 72% (95% confidence interval 54-83%) among 16-18 year-old girls and 51% (14-72%) among boys after the introduction of the female-only qHPV vaccination program. Trends in AGW-related prescriptions were different from trends in AGW diagnoses as these prescriptions peaked shortly after the introduction of the publicly funded qHPV vaccine program. Chlamydia and gonorrhea incidence rates also decreased 12% (5-18%) and 16% (-1-30%), respectively, for 16-18 year-old girls. CONCLUSIONS: The publicly funded school-based qHPV vaccine program reduced AGW incidence in Manitoba by three-quarters in young females. AGW-related prescriptions are a poor proxy for medically attended AGW after the introduction of the publicly funded qHPV vaccination program. Different sexual habits in adolescents are, at most, responsible for a small portion of the reduction in AGW incidence.

Examining the Impact of First Nations Status on the Relationship Between Diabetes and Cancer.

Purpose: This population-based study examined the relationship between diabetes and cancer and determined if this relationship was influenced by First Nations (FN) status. Methods: In a matched case-cohort study, individuals 30-74 years of age diagnosed with diabetes during 1984-2008 in the province of Manitoba, Canada, with no cancer diagnosis before their diabetes diagnosis were matched to one diabetes-free control by age, sex, FN status, and residence. Flexible competing risk and Royston-Parmar regression models were used to compare cancer rates. Results: Overall, 72,715 individuals diagnosed with diabetes were matched to controls. In all age groups, diabetes was related to an increased risk of cancer. The relationship between diabetes and any type of cancer was not influenced by FN status (i.e., there was no interaction between the diagnosis of diabetes and people's FN status for any age group). The only significant interaction between diabetes and FN status was for kidney cancer for individuals 60-74 years of age; diabetes increased the risk of kidney cancer for all other Manitobans (AOMs) but not for FN. Conclusions: Diabetes increased the risk of cancer. The association was not modified by FN status except for kidney cancer where diabetes increased the risk for AOMs but not for FN.

Trends in Prescribing Menopausal Hormone Therapy and Bisphosphonates in Australia and Manitoba, Canada and Adherence to Recommendations.

Background: Recommendations for using menopausal hormone therapy (MHT) and bisphosphonates for postmenopausal osteoporosis management have changed over time. After the release of the Women's Health Initiative (WHI) trial results in 2002, new evidence on risks and benefits of MHT became available, and newer guidelines generally specify that MHT should not be prescribed for prevention of chronic disease, including osteoporosis. This raises the question of whether bisphosphonate prescribing changed over time to compensate for the decrease in MHT use. Materials and Methods: We examined trends in dispensed prescriptions in Australia (national) and Canada (province of Manitoba) in relation to prescribing recommendations. Administrative data were used to describe dispensing patterns and changes for persons of all ages from 1996 to 2008, and for women aged 50 to ≥80 years from 2003 to 2008 in Australia and 1996 to 2008 in Canada. Results: In both geographic settings, MHT dispensing increased 1996-2001, peaked in 2001, and declined substantially thereafter (67% reduction in MHT prescriptions for Australia; 64% reduction for Manitoba, Canada to 2008). From 2003 to 2008, the number of MHT prescriptions declined among all age groups in both settings, with the highest declines among women in their 50s. Concurrently, bisphosphonate dispensing increased until 2005 (2001-2005: 260% increase in the number of prescriptions in Australia; 125% increase in Manitoba) and stabilized thereafter, in both settings. Annual bisphosphonate dispensing rates increased 4.1-10.9% for women in their 70s and 80s in Australia and Manitoba during the period studied. Conclusions: Based on dispensed prescriptions data, more recent guidelines for MHT and bisphosphonates use for postmenopausal osteoporosis, which were updated during the study period (and are still consistent with the current guidelines), appear to have been broadly adhered to in both settings.

Breast cancer incidence by country of birth among immigrant women in British Columbia, Canada.

INTRODUCTION: Breast cancer rates vary internationally and between immigrant and non-immigrant populations. We describe breast cancer incidence by birth region and country in British Columbia, Canada. METHODS: We linked population-based health and immigration databases for a population with >1.29 million immigrants to assess breast cancer incidence among immigrant and non-immigrant women. We report age-standardized incidence ratios (SIRs) by birth region and country using non-immigrant women as the standard. RESULTS: SIRs varied widely by both birth country and region. Low rates were found for South (SIR = 0.52, 95% CI: 0.47,0.59) and East Asian (SIR = 0.75, 95% CI: 0.72,0.79) women and a higher rate for Western Europeans (SIR = 1.15, 95% CI: 1.01,1.30). CONCLUSION: There is considerable variation in SIRs across some of British Columbia's largest immigrant populations and several demonstrate significantly different risk profiles compared to non-immigrants. These findings provide unique data to support breast cancer prevention and control.

Breast screening participation and retention among immigrants and nonimmigrants in British Columbia: A population-based study.

Breast cancer screening programs operate across Canada providing mammography to women in target age groups with the goal of reducing breast cancer mortality through early detection of tumors. Disparities in breast screening participation among socio-demographic groups, including immigrants, have been reported in Canada. Our objectives were to: (1) assess breast screening participation and retention among immigrant and nonimmigrant women in British Columbia (BC), Canada; and (2) to characterize factors associated with screening among screening-age recent immigrant women in BC. We examined 2 population-based cohorts of women eligible for breast screening participation (537 783 women) and retention (281 052 women) using linked health and immigration data. Breast screening rates were presented according to socio-demographic and health-related variables stratified by birth country. Factors associated with screening among recent immigrant women were explored using Poisson regression. We observed marked variation in screening participation across birth country cohorts. Eastern European/Central Asian women showed low participation (37.9%) with rates from individual countries ranging from 35.0% to 49.0%. Participation rates for immigrant women from the most common birth countries, such as China/Macau/Hong Kong/Taiwan (45.7%), India (44.5%), the Philippines (45.9%), and South Korea (39.0%), were lower than the nonimmigrant rates (51.2%). Retention rates showed less variation by birth country; however, some disparities between immigrant and nonimmigrant groups persisted. Associations between screening indicators and study factors varied considerably across immigrant groups. Primary care physician visits were consistently positively associated with screening participation; this variable was also the only predictor associated with screening within each of the groups of recent immigrants. Our study provides unique data on both screening participation and retention among Canadian immigrant women compiled by individual country of birth. Our results are further demonstration that screening disparities exist among immigrant populations as well as in comparison with nonimmigrant women.

Early Evidence of the Effectiveness of the Human Papillomavirus Vaccination Program Against Anogenital Warts in Manitoba, Canada: A Registry Cohort Study.

BACKGROUND: We assessed the effectiveness of the quadrivalent human papillomavirus vaccine (qHPV) vaccination program in Manitoba, Canada, in reducing incident anogenital warts (AGWs) and to what extent effectiveness depends on age at vaccination and number of doses. METHODS: Female participants 9 years or older who received the qHPV in Manitoba between September 2006 and March 2013 (n = 31,464) through the publicly funded school-based program and a high-risk catch-up program were included. They were matched on age and area of residence to unvaccinated female participants. Information on incident AGWs was obtained from provincial administrative databases using validated algorithms. Using stratified Cox regression models, we estimate hazard ratios (HRs) for the association between qHPV and AGWs. RESULTS: For female participants vaccinated at age 18 years or younger, receipt of qHPV was associated with a 40% reduction in AGW risk (HR, 0.6; 95% confidence interval [CI], 0.4-0.8). Further adjustment for socioeconomic and medical history did not alter this estimate. For women vaccinated at age 19 years or older, we saw an increase in AGW incidence, especially among those who were sexually active (HR, 2.8; 95% CI, 2.1-3.7). Among female participants vaccinated at age 18 years or younger, risk of AGWs was lowest among those who received 3 doses, corresponding to a vaccine effectiveness of 56% (95% CI, 30%-70%). For women vaccinated at older age, risk of AGWs remained increased regardless of the number of doses. CONCLUSIONS: Women vaccinated at an older (≥19 years) age may be less protected against AGWs, particularly if sexually active before vaccine administration. Further efforts should be targeted at increasing vaccine uptake among preadolescents before the initiation of sexual activity.

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.

Optimal uptake rates for initial treatments for cervical cancer in concordance with guidelines in Australia and Canada: Results from two large cancer facilities.

BACKGROUND: Prior work estimating optimal treatment utilisation rates for cervical cancer has focused on radiotherapy or chemotherapy, using proportions of patients with clinical indications for specific treatment strategies which were obtained from the published literature. OBJECTIVES: To estimate optimal uptake rates for surgery, radiotherapy, chemotherapy and chemo-radiotherapy for cervical cancer treatment in Australia and Canada, and to quantify the differences in the optimal and the observed treatment utilisation rates in a large cancer facility from each country. METHODS: A decision tree was constructed to reflect treatments according to guidelines and current practice (in 1999-2008) in each setting. Detailed patterns of care data from a large cancer facility in each country were obtained, and the observed stage distribution and proportions of patients with each clinical indication were used as inputs. RESULTS: The estimated overall optimal treatment rates for cervical cancer in Australia and Canada differed, largely due to the difference in the stage distribution at diagnosis in the two settings; 72% vs 54% with FIGO IA-IIA disease, respectively. The estimated optimal rates for surgery, radiotherapy, chemotherapy and chemo-radiotherapy in Australia were 63% (95% credible interval: 61-64%), 52% (53-56%), 36% (35-38%) and 36% (35-38%), respectively. The corresponding rates in Canada were 38% (36-39%), 68% (68-71%), 51% (49-52%) and 50% (49-51%), respectively. The absolute differences between the optimal and the observed rates were similar between the two settings; the absolute differences for chemotherapy and chemo-radiotherapy uptake were more pronounced (9-15% less than optimal) than those for surgery and radiotherapy uptake (within 5% of optimal). CONCLUSIONS: This is the first study to use detailed patterns of care data in multiple settings to compare optimal and observed rates for all cervical cancer treatment modalities. We found optimal treatment rates were largely dependent on the overall stage distribution. In Australia and Canada, observed surgery rates, as measured in the two large cancer facilities, were similar to the estimated optimal rates, whereas radiotherapy, chemotherapy and chemo-radiotherapy appeared to be under-utilised.

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.

Population-level impact and herd effects following human papillomavirus vaccination programmes: a systematic review and meta-analysis.

BACKGROUND: Human papillomavirus (HPV) vaccination programmes were first implemented in several countries worldwide in 2007. We did a systematic review and meta-analysis to assess the population-level consequences and herd effects after female HPV vaccination programmes, to verify whether or not the high efficacy reported in randomised controlled clinical trials are materialising in real-world situations. METHODS: We searched the Medline and Embase databases (between Jan 1, 2007 and Feb 28, 2014) and conference abstracts for time-trend studies that analysed changes, between the pre-vaccination and post-vaccination periods, in the incidence or prevalence of at least one HPV-related endpoint: HPV infection, anogenital warts, and high-grade cervical lesions. We used random-effects models to derive pooled relative risk (RR) estimates. We stratified all analyses by age and sex. We did subgroup analyses by comparing studies according to vaccine type, vaccination coverage, and years since implementation of the vaccination programme. We assessed heterogeneity across studies using I(2) and χ(2) statistics and we did trends analysis to examine the dose-response association between HPV vaccination coverage and each study effect measure. FINDINGS: We identified 20 eligible studies, which were all undertaken in nine high-income countries and represent more than 140 million person-years of follow-up. In countries with female vaccination coverage of at least 50%, HPV type 16 and 18 infections decreased significantly between the pre-vaccination and post-vaccination periods by 68% (RR 0·32, 95% CI 0·19-0·52) and anogenital warts decreased significantly by 61% (0·39, 0·22-0·71) in girls 13-19 years of age. Significant reductions were also recorded in HPV types 31, 33, and 45 in this age group of girls (RR 0·72, 95% CI 0·54-0·96), which suggests cross-protection. Additionally, significant reductions in anogenital warts were also reported in boys younger than 20 years of age (0·66 [95% CI 0·47-0·91]) and in women 20-39 years of age (0·68 [95% CI 0·51-0·89]), which suggests herd effects. In countries with female vaccination coverage lower than 50%, significant reductions in HPV types 16 and 18 infection (RR 0·50, 95% CI 0·34-0·74]) and in anogenital warts (0·86 [95% CI 0·79-0·94]) occurred in girls younger than 20 years of age, with no indication of cross-protection or herd effects. INTERPRETATION: Our results are promising for the long-term population-level effects of HPV vaccination programmes. However, continued monitoring is essential to identify any signals of potential waning efficacy or type-replacement. FUNDING: The Canadian Institutes of Health Research.

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.

Comparative cost-effectiveness of the quadrivalent and bivalent human papillomavirus vaccines: a transmission-dynamic modeling study.

BACKGROUND: The quadrivalent and bivalent human papillomavirus (HPV) vaccines are now licensed in several countries. We compared the cost-effectiveness of the HPV vaccines to provide evidence for policy decisions. METHODS: We developed HPV-ADVISE, a multi-type individual-based transmission-dynamic model of HPV infection and disease (anogenital warts, and cervical, anogenital and oropharyngeal cancers). We calibrated the model to sexual behavior and epidemiologic data from Canada, and estimated quality-adjusted life-years (QALYs) lost and costs ($CAN 2010) from the literature. Vaccine-type efficacy was based on a systematic literature review. The analysis was performed from the healthcare provider perspective, and costs and benefits were discounted at 3%. Predictions are presented using the median [10th;90th percentiles] of simulations. RESULTS: Under base-case assumptions (vaccinating 10-year-old girls, 80% coverage, $95/dose), using the quadrivalent and bivalent vaccines is estimated to cost $15,528 [12,056;19,140] and $20,182 [15,531;25,240] per QALY-gained, respectively. At equal price, the quadrivalent vaccine is more cost-effective than bivalent under all scenarios investigated, except when assuming longer duration of protection for the bivalent and minimal anogenital warts burden. Under base-case assumptions, the maximum additional cost per dose for the quadrivalent vaccine to remain more cost-effective than the bivalent is $32 [17;46] (using a $40,000/QALY-gained threshold). Results were most sensitive to discounting, time-horizon, differences in durations of protection and anogenital warts burden. CONCLUSIONS: Vaccinating pre-adolescent girls against HPV is predicted to be highly cost-effective. If equally priced, the quadrivalent is the most economically desirable vaccine. However, ultimately, the most cost-effective HPV vaccine will be determined by their relative price.

Cervical cancer incidence trends in Canada: a 30-year population-based analysis.

OBJECTIVES: To use the most recent data to update the trend in cervical cancer incidence in Canada over the 30 year period from 1978 to 2009. METHODS: Registered cases of cervical cancer and the corresponding person years for the Canadian population were retrieved from an online data repository of the International Agency on Research on Cancer and from Statistics Canada for the period 1978 to 2009. Annual age-standardized rates were estimated for all data combined and for each province separately. The ages of cases were aggregated into three groups: 25 to 39, 40 to 59, and 60 to 75 years. Joinpoint regression analysis was used to describe the trend across age groups and provinces. RESULTS: Between 1978 and 2006, the age-adjusted cervical cancer rate in Canada decreased from 20.05 to 12.66 per 100 000 females; after 2006 the rate increased. Greater reductions were observed in the older age groups. The average annual percentage change (AAPC) was -1.1% (95% CI -1.1% to 0.09%), -1.8% (95% CI -2.5% to -1.2%), and -2.6% (95% CI -3.9% to -1.4%) for age groups 25 to 39, 40 to 60, and 60 to 75, respectively. The AAPC varied between provinces, ranging from -0.22% (95% CI -1.4% to 0.9%) in Saskatchewan to -3.02% (95% CI -4.5% to -1.5%) in Newfoundland and Labrador. In Ontario the incidence of cervical cancer increased annually between 2006 and 2009. The trend in British Columbia included a significant change of slope in 1984. CONCLUSION: The incidence of cervical cancer decreased in Canada and across all provinces between 1978 and 2009. The decrease was greater in older women.

Objectifs : Utiliser les données les plus récentes pour offrir une mise à jour quant à la tendance pour ce qui est de l'incidence du cancer du col utérin au Canada au cours de la période de 30 ans s'étalant de 1978 à 2009. Méthodes : Les cas enregistrés de cancer du col utérin et les taux correspondants en personnes-années pour la population canadienne ont été récupérés auprès d'un dépôt de données en ligne du Centre International de Recherche sur le Cancer, ainsi qu'auprès de Statistique Canada, pour la période 1978 - 2009. Les taux annuels standardisés en fonction de l'âge ont été estimés pour l'ensemble des données et, de façon distincte, pour chacune des provinces. Les âges des cas ont été agrégés en trois groupes : 25 - 39 ans, 40 - 59 ans et 60 - 75 ans. Une analyse de régression Joinpoint a été utilisée pour décrire la tendance d'un groupe d'âge et d'une province à l'autre. Résultats : Entre 1978 et 2006, au Canada, le taux de cancer du col utérin corrigé en fonction de l'âge est passé de 20,05 à 12,66 par 100 000 femmes; après 2006, le taux a connu une hausse. Des baisses plus importantes ont été constatées au sein des groupes plus âgés. La modification annuelle moyenne en pourcentage (MAMP) était de −1,1 % (IC à 95 %, −1,1 % - 0,09 %), de −1,8 % (IC à 95 %, −2,5 % - −1,2 %) et de −2,6 % (IC à 95 %, −3,9 % - −1,4 %) pour les groupes d'âge de 25 à 39 ans, de 40 à 60 ans et de 60 à 75 ans, respectivement. La MAMP variait d'une province à l'autre, allant de −0,22 % (IC à 95 %, −1,4 % - 0,9 %) en Saskatchewan à −3,02 % (IC à 95 %, −4,5 % - −1,5 %) à Terre-Neuve-et-Labrador. En Ontario, l'incidence du cancer du col utérin a connu une hausse annuelle entre 2006 et 2009. En Colombie-Britannique, la tendance comptait une modification de pente significative en 1984. Conclusion : L'incidence du cancer du col utérin a connu une baisse, au Canada et dans toutes les provinces, entre 1978 et 2009. Cette baisse a été plus accentuée chez les femmes plus âgées.