Evaluation of the First Decade of the Prevention Program for Cervical Cancer in Saskatchewan
Date
2015-04-16
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Journal ISSN
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ORCID
Type
Thesis
Degree Level
Doctoral
Abstract
This dissertation evaluates the effects of Saskatchewan’s Prevention Program for Cervical Cancer (PPCC) in its first decade of operation (2000-2011). Launched in August 2003, the PPCC is an organized population-based program that encourages participation in Pap smear testing within timeframes consistent with medical screening guidelines. All eligible women for whom the PPCC database does not have a test result are mailed a letter of invitation to participate in screening, including women who turn 18 or who are new residents of Saskatchewan. Once Pap test results are in the database, clients are mailed results and reminder letters to return to screening at the recommended time. Clients whose first test result is normal are recalled one year later. After two consecutive normal test results, recall occurs after three years. Clients with an abnormal-low result are recalled after six months and those clients with a test result of abnormal-high are referred to a physician for immediate follow-up within six weeks.
This study has the following three objectives: (1) Evaluate overall, age-specific, and age-standardized screening participation rates in Saskatchewan before and after the introduction of the PPCC and ascertain change patterns over time. (2) Evaluate whether the participation rate is affected by urban/rural residential location and socioeconomic status of eligible women living in urban areas. (3) Examine the pattern of follow-up visits for women before and after the introduction of the PPCC.
The Saskatchewan Cancer Agency’s administrative cervical cancer screening database includes Pap tests provided to female clients between 20-69 years of age from 2000 to 2011.
Spline analysis was used to identify patterns of change over time before and after the implementation of the PPCC and survival analysis was employed to investigate patterns of follow-up visits. Results show that the introduction of the PPCC initially increased the three-year rolling participation rates. Participation reached its zenith (64.7%) in 2002-2004, and fell thereafter reaching 60.9% in 2009-2011; a rate even lower than before the PPCC started (62.7%). Spline analysis confirmed the statistically significant upward and downward trends both before and after peak participation was reached in the 2002-2004 period.
Younger women were more likely to participate in Pap smear testing than older women, although older women were more likely to comply with follow-up after abnormal-low results. Women living in urban areas were about 10-20% more likely to take the test than those living in rural areas. Women in lower income quintile areas were significantly less likely to take the test than those living in higher income quintile areas with approximately a 3% difference in participation at each income quintile level.
Survival analysis found that subsequent screening visits for those who had already participated can be roughly divided into the following two groups: women who chose to undergo annual testing regardless of how many normal test results they received (i.e., essentially disregarding clinical guidelines) and women who followed no clear schedule.
A significant finding of this study was that the ratio of invitation to result letters received by clients served as a predictor for participation rates. The invitation letter strongly encourages women to screen. As 95% of the screen results are normal, most result letters direct women to return to screen after a three-year interval as stated in clinical guidelines. When the PPCC started, most women received invitation letters. Over time, an increasing proportion of women received result letters because most of them had already been screened multiple times. Given that participation rate is calculated for all eligible women, this ratio of the two letter types suggests that participation would initially increase and then decrease over time.
The findings of this study support previous research on the impact of socioeconomic status (SES) on cancer screening participation. The model proposed in this study partially explains both the initial increase and the subsequent decrease in participation rate. It can serve as a working hypothesis to be tested with data from other similar screening programs.
These results show that the PPCC had a positive impact, especially in the first few years of its operation and that its operational protocol can be modified to increase the overall participation rate in the future. These results also suggest that measures to improve participation be implemented, especially among the unscreened or among women from lower SES neighbourhoods or rural areas.
Description
Keywords
Cervical cancer, screening, Urban, Rural, socioeconomic Status
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Community Health and Epidemiology
Program
Community and Population Health Science