Post-colposcopy Management of ASC-US and LSIL Pap Tests (PALS Trial): Pilot RCT

Evidence supporting optimal follow-up of women with atypical squamous cells of undetermined significance (ASC-US) or low-grade squamous intraepithelial lesion cytology found to have low-grade disease or normal findings at initial colposcopy is weak. Surveillance options include continued colposcopy, discharge with Pap testing, or HPV testing at 12 months. This study was a pilot RCT comparing these three follow-up policies. The objectives were to determine the feasibility of an RCT and to compare the incidence of greater than or equal to high-grade squamous intraepithelial lesion (≥HSIL) in each of the follow-up policies.

A total of 133 women referred with ASC-US or low-grade squamous intraepithelial lesion cytology between June and August 2012 underwent initial colposcopy where incident ≥HSIL histology was ruled out. Of these women, 125 were randomly assigned to colposcopic surveillance, Pap testing, or HPV testing. Patients with high-risk results at any point were treated according to standard of care. Patient recruitment and adherence to follow-up were calculated using descriptive statistics. Accuracy of the three follow-up arms was calculated (Canadian Task Force Classification: IC).

Recruitment rates were 80%, and adherence to protocol was 85% to 100%. Nine of 125 (7.2%) patients overall were found to have ≥HSIL histology at exit: one of 43 in the reference colposcopy group, and six of 41 and three of 41 in Pap and HPV arms, respectively. One early cancer was detected in the HPV arm. Sensitivity and specificity (CI) for each arm, respectively, were as follows: colposcopy N/A, 100% (88.1%-100%); Pap, 100% (47.8%-100%) and 85.7% (63.7%-97%); and HPV, 66.7% (9.4%-99.2%) and 68% (46.5%-85.1%).

This pilot study demonstrated the operational and safety feasibility of an RCT in this patient population. Validation of clinical findings is necessary.