Pap tests in the diagnosis of cervical cancer: Help or hinder?

Abstract

Objective: To evaluate the impact of pap tests on the time to diagnosis of cervical cancer.

Methods: In this population-based retrospective cohort study, Ontario women ≥21 years diagnosed with cervical cancer between 2011 and 2014 were identified and database data collected. The presence or absence of a pap test 0-2 years preceding cancer diagnosis was identified. Descriptive and modelling analyses were performed to determine the effect of pap results on cancer diagnosis.

Results: 2002 patients were identified, 75% received a pap test. 1250 patients had known cytology - 13% normal, 8% low-grade and 7.5% suspicious for cancer. Across all FIGO stages at diagnosis, 5-10% of cytology was low grade, 3-11.5% was positive for carcinoma and 4-41% was normal, which increased with advancing stage. For all cytology and FIGO stages (except stage 1A), OBGYNs had a significantly shorter time to diagnosis compared to family physicians. Factors increasing the odds of low-grade cytology were advanced stage (OR 4.5 (2.4-8.0), p < 0.01) and adenocarcinoma (OR 1.5 (1.1-2.1), p < 0.01). Low grade cytology resulted in the longest delay to diagnosis (p < 0.001).

Conclusion: Pap tests are performed frequently in the 0-2 years prior to the diagnosis of cervical cancer which can result in false negative cytology and diagnostic delay in patients with advanced cancers.

Keywords: Cervical cancer; Cervix; Cytology; Neoplasms; Pap smear; Pap test; Screening.