Screening in Underserved Populations

What are we measuring and why?

This special feature presents data on variations in cancer screening rates by household income and immigrant status, focusing on breast, colorectal and cervical cancers. The indicators are based on self-reported data from the 2012 Canadian Community Health Survey (CCHS).

• A 2014 report from the Canadian Partnership Against Cancer (Examining Disparities in Cancer Control) looked at inequalities in screening by household income, geography and immigrant status using data from the 2008 CCHS.¹ This special feature provides an update to that report by including more current data on household income and immigrant status.
• There is substantial evidence that cancer screening rates are lower among Canadians with low socioeconomic status (SES) than they are among those with higher SES, despite a system of universal health care.^2-4
• Research has also shown that new immigrants to Canada tend to underutilize cancer screening services compared to people who were born in Canada.^4-6 This trend has also been observed in other countries.⁷
• The Canadian Partnership Against Cancer’s System Performance Targets and Benchmarks Working Group recently established national targets for screening by household income and by immigrant status, as follows (see What do the results mean? for more information on these targets):
  • Cervical cancer screening target: 80% screened.
  • Breast cancer screening target: 70% screened.

What are the results?

Cervical cancer screening (Figure 2.6)

• In 2012, lower-income women (aged 21-69) were less likely to report having been screened for cervical cancer than their higher-income counterparts. In the lowest income quintile (Q1), 69.2% of women reported having a Pap test in the previous three years compared to 84.5% of those in the highest-income quintile (Q5). Screening rates in the highest three income quintiles (Q3-Q5) met the target of 80% set for this indicator.
• Like lower-income women, recent immigrants were less likely to report having undergone cervical cancer screening: 65.0% of women who had lived in Canada for less than 10 years reported having a Pap test in the previous three years (compared to 81.8% of Canadian-born women). This disparity in screening rates decreased as immigrants remained in Canada for a longer period of time (10 years or more). Canadian-born women were the only group whose cervical cancer screening rates met the 80% target set for this indicator.

Breast cancer screening (Figure 2.7)

• In 2012, lower-income women (aged 50-69) were less likely to be screened for breast cancer than higher-income women. In the lowest income quintile (Q1), 62.3% of women reported having undergone a screening mammogram in the previous two years compared to 80.5% of those in the highest-income quintile (Q5). Screening rates in all income quintiles except Q1, which is the lowest, met the target of 70% set for this indicator.
• There was no real difference in self-reported breast cancer screening rates among women based on their immigrant status; rates in all groups were above the 70% target set for this indicator. The difference between recent immigrants (<10 years in Canada) and Canadian-born women was just 1.9 percentage points (within the statistical margin of error). Note that this pattern is different than one previously reported, using 2008 data; these data showed breast cancer screening rates among immigrants who had lived in Canada for less than 10 years were substantially lower than the screening rates among Canadian-born women.

Colorectal cancer screening (Figure 2.8)

• Colorectal cancer screening rates were lower than breast or cervical screening rates, regardless of income or immigrant status—most likely because this type of cancer screening has been in place for the shortest time period.
• In 2012, lower-income Canadians (aged 50-74) were less likely to report having been screened for colorectal cancer than those in higher-income groups. In the lowest-income quintile (Q1), 36.4% of people reported being up-to-date on their colorectal cancer screening, compared to 50.1% of those in the highest-income quintile (Q5).
• Recent immigrants were also less likely to report that they had undergone colorectal cancer screening; 27.1% of respondents who had lived in Canada for less than 10 years reported they were up-to-date on their screening, compared to 44.3% of Canadian-born respondents. (However the rate for new immigrants should be interpreted with caution due to small sample size and large variability in the estimate). The disparity between screening rates decreased as immigrants remained in Canada for a longer period of time (10 years or more). In fact, longer-term immigrants had the highest self-reported colorectal cancer screening rates.

What do the results mean?

• While cancer screening in Canada has been effective, disparities in screening participation still exist among certain groups, including recent immigrants and people from low-income households. Future efforts should focus on more equitable access to and increased use of cancer screening among these underserved populations.
• In 2015, for the first time, system performance targets were set for cervical and breast cancer screening in underserved populations, both by household income and by immigrant status. The targets were set by experts from the Partnership’s System Performance Targets and Benchmarks Working Group, who recommended alignment with participation targets set by the screening networks: 80% for cervical cancer screening and 70% for breast cancer screening across all income quintiles and immigrant statuses. Note that because income analysis was done using CCHS data at the national level, provinces may be unable to replicate the results when analysis is restricted to an individual province. The goal of this target is to direct interventions at women in the lowest income quintiles (where screening rates have not yet reached the set targets), underscoring the importance of screening women in underserved populations. The ultimate goal of setting screening targets by household income and by immigrant status is to improve overall screening rates across Canada and reduce disparities in access to cancer screening services over time. (Note that a target was not set for colorectal cancer screening by income because the screening network target is specific to fecal testing; this Special Feature reports on overall up-to-datedness in colorectal cancer screening).
• When it comes to cervical and colorectal cancer screening, the results show that screening rates were higher among longer-term immigrants (i.e., those who had lived in Canada for 10 years or more) than they were among more recent immigrants. This is consistent with previous research showing that screening rates increased slowly with each year immigrants remained in Canada.^7,8
• Additional data from the Partnership (not shown) indicate that observed disparities in cervical cancer screening by income and immigrant status persisted over time (from 2003 to 2012). For breast cancer screening, disparities by income increased between 2005 and 2012; however, by 2012, no disparities in breast cancer screening were observed in immigrant women.⁹
• Barriers to screening exist for immigrant and low-income populations. These could negatively influence screening uptake and self-reported screening participation rates. Such barriers may include: a lack of knowledge about screening; a lack of resources which prevents people from using screening services (i.e., they may be unable to afford transportation and/or lack affordable child care services); poor health literacy (i.e., not understanding what cancer is, why screening is important and how to access services); and the language and gender of the person’s physician.^{7, 10-12} Encouraging physicians, policy-makers and screening programs to recognize and understand these barriers may improve accessibility which could eventually translate into better uptake of screening within these underserved populations.

References

1. Canadian Partnership Against Cancer. Examining disparities in cancer control: A system performance special focus report. Toronto: Canadian Partnership Against Cancer, 2014.
2. Lofters AK, Hwang SW, Moineddin R, Glazier RH. Cervical cancer screening among urban immigrants by region of origin: a population-based cohort study. Prev Med. 2010;51(6):509-16.
3. Katz SJ, Hofer TP. Socioeconomic disparities in preventive care persist despite universal coverage. Breast and cervical cancer screening in Ontario and the United States. JAMA. 1994;272(7):530-4.
4. Ahmed S, Shahid RK. Disparity in cancer care: a Canadian perspective. Curr Oncol. 2012;19(6):e376-82.
5. National Outreach Team of the Canadian Partnership Against Cancer. Cancer Care for All Canadians: Improving Access and Minimizing Disparities for Underserved Populations. Toronto: Canadian Partnership Against Cancer, 2008.
6. Amankwah E, Ngwakongnwi E, Quan H. Why many visible minority women in Canada do not participate in cervical cancer screening. Ethn Health. 2009;14(4):337-49.
7. McDonald JT, Kennedy S. Cervical cancer screening by immigrant and minority women in Canada. J Immigr Minor Health. 2007;9(4):323-34.
8. Latif E. Recent immigrants and the use of cervical cancer screening test in Canada. J Immigr Minor Health. 2010;12(1):1-17.
9. Kerner J, Liu J, Wang K, Fung S, Landry C, Lockwood G, et al. Canadian cancer screening disparities: A recent historical perspective. Current Oncology 2015;22(2):156-63.
10. Lofters AK, Moineddin R, Hwang SW, Glazier RH. Predictors of low cervical cancer screening among immigrant women in Ontario, Canada. BMC Womens Health. 2011;11:20.
11. Assembly of First Nations. Access to Cancer Screening and First Nations. Assemby of First Nations, 2009.
12. Gordon-Dseagu V. Cancer and health inequalities: An introduction to current evidence. London: Cancer Research UK, 2006.