Randomized Clinical Trial on Clinical Management of ASCUS and LSIL (ALTS)

Approximately 65 million Pap smears are performed each year in the United States. The vast majority of results are negative (no abnormality identified) but about 5 percent to 8 percent are reported as abnormal. Most low-grade changes regress spontaneously; only a minority of such lesions would progress to a cancer precursor without treatment. However, there is no way to determine morphologically which patients are at risk of progression. Therefore, both high- and low-grade lesions were often managed with colposcopy and directed biopsy. It was anticipated that determining alternative management strategies would yield important potential benefits including fewer medical complications from over treatment, reduced patient anxiety associated with referral for cytologic abnormalities, as well as cost savings.

Epidemiologic, virologic and molecular studies have clearly demonstrated that human papillomavirus (HPV) is the central cause of cervical cancer. The motivation for the ALTS trial was to use the information we have gained about the role of HPV to design better treatment and prevention strategies to reduce the burden of cervical cancer and its precursors.

ALTS consisted of three management strategies: (1) immediate colposcopy of all women; (2) repeat cytology with colposcopy only if the results show a high grade lesion; and (3) HPV testing and repeat cytology in combination, with referral to colposcopy if either the HPV test is positive or the cytology shows a high grade lesion. Four Clinical Centers University of Alabama, Birmingham AL; Magee-Womens Hospital, Pittsburgh PA; University of Oklahoma, Oklahoma City OK; and University of Washington, Seattle WA - enrolled approximately 5,000 women with recent diagnosis of ASCUS or LSIL. Participants were followed at six month intervals for a total of 2 years. The main results from ALTS showed that for women with ASCUS cytology, HPV triage was at least as safe as universal immediate colposcopy in the detection of high-grade lesion and would allow approximately half of women to return to routine follow up without additional procedures (colposcopy). No efficient triage strategy was identified for women with LSIL cytology.

The ALTS database and ALTS specimens continue to be a valuable research resource in studies of cervical cancer precursors, screening tests, visual assessment of the cervix and investigation of biomarkers.