COVID-19 pandemic impact on the potential exacerbation of screening mammography disparities: A population-based study in Ontario, Canada

Strategies to ramp up breast cancer screening after COVID-19 require data on the influence of the pandemic on groups of women with historically low screening uptake. Using data from Ontario, Canada, our objectives were to 1) quantify the overall pandemic impact on weekly bilateral screening mammography rates (per 100,000) of average-risk women aged 50-74 and 2) examine if COVID-19 has shifted any mammography inequalities according to age, immigration status, rurality, and access to material resources. Using a segmented negative binomial regression model, we estimated the mean change in rate at the start of the pandemic (the week of March 15, 2020) and changes in weekly trend of rates during the pandemic period (March 15-December 26, 2020) compared to the pre-pandemic period (January 3, 2016-March 14, 2020) for all women and for each subgroup. A 3-way interaction term (COVID-19*week*subgroup variable) was added to the model to detect any pandemic impact on screening disparities. Of the 3,481,283 mammograms, 8.6 % (n = 300,064) occurred during the pandemic period. Overall, the mean weekly rate dropped by 93.4 % (95 % CI 91.7 % - 94.8 %) at the beginning of COVID-19, followed by a weekly increase of 8.4 % (95 % CI 7.4 % - 9.4 %) until December 26, 2020. The pandemic did not shift any disparities (all interactions p > 0.05) and that women who were under 60 or over 70, immigrants, or with a limited access to material resources had persistently low screening rate in both periods. Interventions should proactively target these underserved populations with the goals of reducing advanced-stage breast cancer presentations and mortality.

Factors associated with attendance at screening for breast cancer: a systematic review and meta-analysis

OBJECTIVE

Attendance at population-based breast cancer (mammographic) screening varies. This comprehensive systematic review and meta-analysis assesses all identified patient-level factors associated with routine population breast screening attendance.

DESIGN

CINAHL, Cochrane Library, Embase, Medline, OVID, PsycINFO and Web of Science were searched for studies of any design, published January 1987-June 2019, and reporting attendance in relation to at least one patient-level factor.

DATA SYNTHESIS

Independent reviewers performed screening, data extraction and quality appraisal. OR and 95% CIs were calculated for attendance for each factor and random-effects meta-analysis was undertaken where possible.

RESULTS

Of 19 776 studies, 335 were assessed at full text and 66 studies (n=22 150 922) were included. Risk of bias was generally low. In meta-analysis, increased attendance was associated with higher socioeconomic status (SES) (n=11 studies; OR 1.45, 95% CI: 1.20 to 1.75); higher income (n=5 studies; OR 1.96, 95% CI: 1.68 to 2.29); home ownership (n=3 studies; OR 2.16, 95% CI: 2.08 to 2.23); being non-immigrant (n=7 studies; OR 2.23, 95% CI: 2.00 to 2.48); being married/cohabiting (n=7 studies; OR 1.86, 95% CI: 1.58 to 2.19) and medium (vs low) level of education (n=6 studies; OR 1.24, 95% CI: 1.09 to 1.41). Women with previous false-positive results were less likely to reattend (n=6 studies; OR 0.77, 95% CI: 0.68 to 0.88). There were no differences by age group or by rural versus urban residence.

CONCLUSIONS

Attendance was lower in women with lower SES, those who were immigrants, non-homeowners and those with previous false-positive results. Variations in service delivery, screening programmes and study populations may influence findings. Our findings are of univariable associations. Underlying causes of lower uptake such as practical, physical, psychological or financial barriers should be investigated.

TRIAL REGISTRATION NUMBER

CRD42016051597.

Periodic screening for breast and cervical cancer in women with diabetes: a population-based cohort study

PURPOSE

Diabetes is associated with poorer cancer outcomes. Screening for breast and cervical cancer is recommended by clinical guidelines; however, utilization of these tests in people with diabetes has been unclear due to methodological limitations in the evidence base. We used administrative data to determine the association between diabetes and the rates of becoming up-to-date with periodic breast and cervical cancer screening over a 20-year period.

METHODS

Healthcare databases from Ontario, Canada, were linked to assemble two population-based cohorts of 50-70 and 21-70 year-olds between 1994 and 2011, eligible for breast and cervical cancer screening, respectively. Using age as the time scale, multivariable recurrent events models were implemented to examine the association between the presence of diabetes and the rates of becoming up-to-date with the recommended cancer screenings.

RESULTS

In each of the breast and cervical cancer screening cohorts, there were, respectively, 1,516,302 (16% had diabetes at baseline) and 4,751,220 (9.5% had diabetes at baseline) screen-eligible women. In multivariable models, prevalent diabetes (duration ≥ 2 years) was associated with lower rates of becoming up-to-date with cervical (hazard ratio, HR 0.85, 95% confidence interval, CI 0.84-0.85) and breast (HR 0.94, CI 0.93-0.94) cancer screening, compared to no diabetes.

CONCLUSIONS

Having diabetes is associated with decreased rates of becoming up-to-date with two recommended periodic cancer screenings, with a bigger reduction in the rates of becoming up-to-date with cervical cancer screening. Greater attention to cervical cancer preventive services is needed in women with diabetes.

Patient and provider determinants of breast cancer screening among Ontario women aged 40-49: a population-based retrospective cohort study

PURPOSE

Canadian breast cancer screening guidelines state that mammography screening for women 40-49 should be individualized based on risk assessment and preferences. This retrospective cohort study describes the frequency of screening in women aged 40-49 and identifies patient and provider-level associations with screening.

METHODS

Administrative databases were linked. The overall cohort included Ontario women aged 40-49 between April 1, 2009 and March 31, 2019. Subgroups were created: the "screen" group included women who received a mammogram defined as screening (using a set of exclusion criteria) and the "routine screen" group included women with three or more screening mammograms. A multivariable multilevel logistic regression model accounting for patient and provider characteristics was fit to determine characteristics associated with routine screening. The intracluster correlation co-efficient was used to quantify the degree of variation across providers.

RESULTS

Of approximately 2 million eligible women, there were 532,596 (25.5%) in the screen group and 90,651 (4.3%) the routine screen group. There was an average of 0.30 and 0.52 screening mammograms per woman year, in the screen and routine screen groups, respectively. Routine screening was associated with periodic health exams (OR 1.21, 95% CI 1.20-1.22), receiving pap smears (OR 1.38, 95% CI 1.37-1.39), and fee-for-service models of care (OR 1.32, 95% CI 1.27-1.36). Over 20% of the variation in screening was due to systematic between-provider differences.

CONCLUSIONS

Approximately 4.3% of women aged 40-49 in Ontario received routine breast cancer screening with substantial variation across providers. Routine screening is associated with periodic health examinations, receipt of pap smears, and fee-for-service models of care.

Influence of chronic comorbidities on periodic colorectal cancer screening participation: A population-based cohort study

Guidelines recommend regular screening for colorectal cancer (CRC). We examined the effects of chronic comorbidities on periodic CRC testing. Using linked healthcare databases from Ontario, Canada, we assembled a population-based cohort of 50-74-year olds overdue for guideline-recommended CRC screening between April 1, 2004 and March 31, 2016. We implemented multivariable recurrent events models to determine the association between comorbidities and the rate of becoming up-to-date with periodic CRC tests. The cohort included 4,642,422 individuals. CRC testing rates were significantly lower in persons with renal disease on dialysis (hazard ratio, HR 0.66, 95% confidence interval, CI 0.63 to 0.68), heart failure (HR 0.75, CI 0.75 to 0.76), respiratory disease (HR 0.84, CI 0.83 to 0.84), cardiovascular disease (HR 0.85, CI 0.84 to 0.85), diabetes (HR 0.86, 95% CI 0.86 to 0.87) and mental illness (HR 0.88, CI 0.87 to 0.88). There was an inverse association between the number of medical conditions and the rate of CRC testing (5 vs. none: HR 0.30, CI 0.25 to 0.36; 4 vs. none: HR 0.48, CI 0.47 to 0.50; 3 vs. none: HR 0.59, CI 0.58 to 0.60; 2 vs. none: HR 0.72, CI 0.71 to 0.72; 1 vs. none: HR 0.85, CI 0.84 to 0.85). Having both medical and mental comorbidities was associated with lower testing rates than either type of comorbidity alone (HR 0.72, CI 0.71 to 0.72). In summary, chronic comorbidities present a barrier to periodic guideline-recommended CRC testing. Exploration of cancer prevention gaps in these populations is warranted.

Combined Effect of Health Status and Primary Care Use on Participation in Cancer Screening: The CONSTANCES Cohort

Background:

The combined association between primary care utilization and health status with breast cancer screening (BCS) and cervical cancer screening (CCS) remains unclear. Our aim was to identify women's profiles based on their health status and primary care utilization and study their associated adherence to BCS and CCS recommendations.

Methods:

Using data from the cohort of people visiting health screening centers (CONSTANCES) in France (2012–2015), we first identified women's profiles based on their health status (self-perceived health, physical, and mental health) and primary care utilization (visit to the General Practitioner [GP], uptake of blood tests) using a multiple correspondence analysis and a hierarchical cluster analysis. We then investigated the association of these profiles to BCS and CCS using logistic regression models adjusted for age, smoking status, sociodemographic and socioeconomic characteristics, and the regularity of gynecologist consultation.

Results:

We identified five distinct profiles of women with contrasted participation in BCS (n = 14,122) and CCS (n = 27,120). In multivariate analyses, cancer screening participation increased from women with very good health and poor primary care utilization, to those with poor health and frequent visits to the GP, and those with very good health and average primary care utilization. The most favorable profiles regarding cancer screening rates were women with average-to-poor health and regular visits to the GP and uptake of blood tests.

Conclusions:

Our results suggest that policies aiming at increasing cancer screening participation should simultaneously account for women's use of primary care and health and consider more specific subgroups than what is usually done. Further research should investigate factors motivating cancer screening practice, such as women's beliefs regarding cancer screening and women's psychological characteristics.

Immigration and Adherence to Cervical Cancer Screening: A Provincewide Longitudinal Matched Cohort Study Using Multistate Transitional Models

OBJECTIVE

Previous studies highlighting inequities in cancer screening between immigrants and non-immigrants have been methodologically limited. This longitudinal matched cohort study used a multistate modelling framework to examine associations between immigration status and cervical cancer screening adherence.

METHODS

A 1:1 matched cohort of women aged 25 and older from 1992-2014 who were residing in Ontario was examined. For each woman, the proportion of time spent being non-adherent was determined. Disparities in cervical screening adherence, and specifically the association between immigration status and the rate of becoming adherent, were investigated with a three-state transitional model. The model was adjusted for individual- and physician-level characteristics, which were updated annually and incorporated as time-varying covariates.

RESULTS

The matched cohort consisted of 1 156 720 immigrant and non-immigrant women. The median proportion of time spent non-adherent was 38.9% for immigrants and 24.7% for non-immigrants. The rate of becoming adherent among immigrants was lower than that among non-immigrants, after accounting for individual- and physician-level characteristics (relative rate 0.933; 95% CI 0.928-0.937). Other characteristics such as socioeconomic status, immigrant region of origin, presence of primary physician, and physician's sex were found to be significantly associated with cervical screening adherence.

CONCLUSION

This study assessed the association between immigration status and adherence to cervical cancer screening. The insights from this work can be used to target groups of women vulnerable to underscreening and to minimize their time spent non-adherent to cancer screening. The methodology serves as a useful framework for examining adherence to other types of cancer screening.

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.

Uptake of Cancer Screening Tests Among Recipients of Solid Organ Transplantation

Population-based cancer screening recommendations are also suggested for solid organ transplant recipients (SOTR); however, recommendation adherence is unknown. In a population-based cohort of SOTR in Ontario between 1997 and 2010, we determined the uptake of breast, cervical, and colorectal cancer screening tests and identified factors associated with up-to-date screening using recurrent event analysis. We identified 4436 SOTR eligible for colorectal, 2252 for cervical, and 1551 for breast cancer screening. Of those, 3437 (77.5%), 1572 (69.8%), and 1417 (91.4%), respectively, were not up-to-date for cancer screening tests during the observation period. However, these rates are likely an overestimate due to the inability to differentiate between tests done for screening or for diagnosis. SOTR with fewer comorbidities had higher rates of becoming screen up-to-date. Assessment by a primary care provider (PCP) was associated with becoming up-to-date with cancer screening (breast relative risk [RR] = 1.40, 95% confidence interval [CI]: 1.12-1.76, cervical RR = 1.29, 95% CI: 1.06-1.57, colorectal RR = 1.30, 95% CI: 1.15-1.48). Similar results were observed for continuity of care by transplant specialist at a transplant center. In conclusion, cancer screening for most SOTR does not adhere to standard recommendations. Involvement of PCPs in posttransplant care and continuity of care at a transplant center may improve the uptake of screening.