The association between cervical cancer screening and mortality from cervical cancer: A population based case–control study

OBJECTIVE: To estimate the effect of cervical cancer screening on mortality from cervical cancer in women between the ages of 20 and 69 residing in Ontario by 5 year age groups. METHODS: An Ontario population based case-control study of women between ages 20 and 69 was performed. Cases were women who were diagnosed with cervical cancer between January 1, 1998 and December 31, 2008 who died from cervical cancer within this period. Controls were women without a diagnosis of cervical cancer between January 1, 1998 and December 31, 2008 who were alive on the case's date of death. Exposure was defined as cervical cytology history. Conditional logistic regression was used to estimate the strength of association between mortality from cervical cancer and screening in 5 year incremental age intervals. RESULTS: We identified 1052 cases and 10,494 controls. Less than 2.5% of women who died from cervical cancer were under the age of 30. Cervical cancer screening performed 3-36 months prior to the date of diagnosis was found to be protective of mortality from cervical cancer in women over the age of 30 (odds ratio=0.28-0.60; p<0.05 in all strata). In women under the age of 30 cervical cancer screening was not found to be protective of mortality from cervical cancer (odds ratio=1.58-2.43; non significant). CONCLUSION: No association between cervical cancer screening and mortality from cervical cancer under the age of 30 was found. This could be due to there being a small or having no effect or due to the fact that mortality from cervical cancer under the age of 30 is extremely rare.