RESUMO
OBJECTIVE: To determine the baseline and cumulative risks of cervical intraepithelial lesion grade 3 (CIN3) and invasive cervical cancer in patients with <CIN2 colposcopy findings after a low-grade screening cytology finding (atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion [LSIL]). METHODS: By linking administrative databases, including cytology, pathology, cancer registries, and physician billing history, a population-based cohort study was performed on participants with <CIN2 initial colposcopy results after a low-grade antecedent cytology finding, between January 2012 and December 2013. Three and 5-year risks of CIN3 and invasive cervical cancer were generated using Kaplan-Meier survival analysis. RESULTS: Among the 36 887 participants included in the study, CIN3 incidence based on referral cytology were as follows at 3 and 5 years, respectively: normal, 0.7% and 0.9%; ASCUS, 4.31% and 5.6%; and LSIL, 5.9% and 7.2%. Three- and 5-year incidence of invasive cancer were 0% and 0.02% for normal cytology, 0.08% and 0.11% for ASCUS, and 0.04% and 0.07% for LSIL, respectively. Stratifying risk by biopsy result at initial colposcopy, 3- and 5-year CIN3 incidences were 2.85% and 3.81% with a negative biopsy, 7.09% and 8.32% with an LSIL biopsy, and 4.11% and 5.2% when no biopsy was done, respectively. Three- and 5-year incidence of invasive cancer was 0% and 0.05% after a negative biopsy, 0% and 0% after LSIL biopsy, and 0.05% and 0.08% when no biopsy was done, respectively. CONCLUSION: When initial colposcopy is done after a low-grade screening cytology result and <CIN2 is identified, the risk of CIN3 and invasive cancer is low, particularly when biopsies indicate LSIL. Surveillance strategies should balance the likelihood of detecting CIN3 with the potential harms over management with too frequent screening or colposcopic interventions in low-risk patients.