Key Programs
The ASCUS/LSIL Triage Study for Cervical Cancer (ALTS)
Main Findings
HPV testing is sensitive in detecting underlying precancerous lesions among women with a Pap test diagnosis of ASCUS.
This study looked at the ALTS patients with ASCUS who were found to have a precancerous lesion when they underwent colposcopy and biopsy. Its purpose was to find out how sensitive HPV testing was at identifying these women compared to repeat Pap testing. The study found that HPV testing was 96-percent sensitive - that is, identified 96% of the women with ASCUS who had a precancerous lesion. The authors concluded that HPV testing is a viable option for the management of ASCUS. Reference: D. Solomon, M. Schiffman, R. Tarone for the ALTS Group, Comparison of Three Management Strategies for Patients With Atypical Squamous Cells of Undetermined Significance: Baseline Results From a Randomized Trial, Journal of the National Cancer Institute, Feb 21, 2001:92(12):293-299).
HPV testing is not useful for women with a Pap test diagnosis of LSIL.
This study focused on the 642 women in the ALTS study who had an LSIL diagnosis, seeking to determine whether HPV testing could be used to decide which of them needed to undergo colposcopy and which could wait, pending the outcome of repeat testing. The authors found that 82.9 percent of women with LSIL tested positive for HPV. They conclude that this high prevalence of HPV limits the usefulness of HPV testing in deciding how to manage LSIL. Reference: Human Papillomavirus Testing for Triage of Women With Cytologic Evidence of Low-Grade Squamous Intraepithelial Lesions: Baseline Data From a Randomized Trial. The ASCUS/LSIL Study (ALTS) Group, Journal of the National Cancer Institute, Mar 1, 2000: 92 (5):397-402.
Expert interpretations of Pap tests vary substantially.
The purpose of this analysis was to determine how often pathologists agree in their interpretations of both Pap tests and cervical biopsy specimens. The researchers compared different pathologists' diagnoses of the thin-layer Pap tests and biopsy specimens that were collected when women enrolled in ALTS. They found substantial differences among expert pathologists in interpreting both thin-layer Pap tests and biopsies; agreement (reproducibility) was only moderate. They conclude that variability among experts in interpreting Pap tests and biopsies should be taken into consideration when using these interpretations and when developing standards of practice. Reference: Stoler, M.H. and Schiffman, M., Interobserver Reproducibility of Cervical Cytologic and Histologic Interpretations: Realistic Estimates From the ASCUS-LSIL Triage Study, Journal of the American Medical Association, Mar. 21, 2001: 285(11),1500-1505.
