The major potential harm of screening for cervical cancer lies in the detection of many lesions such as atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesions (LSIL) that would never progress to cervical cancer. Women with LSIL or high-grade squamous intraepithelial lesions (HSIL) on Papanicolaou (Pap) testing are usually referred for colposcopy and treated with cryotherapy or loop electrosurgical excision procedure. These procedures permanently alter the cervix and have unknown consequences on fertility and pregnancy. Because younger women are most likely to acquire human papillomavirus infections and to be diagnosed with LSIL, they are thus most likely to suffer harms from interventions for a condition that often resolves spontaneously.

Based on an analysis of screening records from nearly 350,000 women in Bristol, England, investigators projected that 1,000 women would need to be screened for cervical cancer for 35 years to prevent one death from the disease.[1] For each death prevented, the authors estimated that over 150 women have an abnormal result, over 80 are referred for investigation, and over 50 have treatment.

Annually in the United States, 50 million women undergo screening; about 3.5 million (7%) will be referred for further evaluation. Of these, more than 2 million will be referred for further evaluation of ASCUS.[2] About 11,000 cases of invasive cervical cancer are expected in 2007. Thus, Pap test screening results in a large number of colposcopies for benign conditions. Strategies to improve the specificity of the cervical cytopathology test are being evaluated by the ASCUS/LSIL Triage Study (ALTS).[3]

References

1. Raffle AE, Alden B, Quinn M, et al.: Outcomes of screening to prevent cancer: analysis of cumulative incidence of cervical abnormality and modelling of cases and deaths prevented. BMJ 326 (7395): 901, 2003.  [PUBMED Abstract]
   
   
2. Solomon D, Schiffman M, Tarone R, et al.: Comparison of three management strategies for patients with atypical squamous cells of undetermined significance: baseline results from a randomized trial. J Natl Cancer Inst 93 (4): 293-9, 2001.  [PUBMED Abstract]
   
   
3. Schiffman M, Adrianza ME: ASCUS-LSIL Triage Study. Design, methods and characteristics of trial participants. Acta Cytol 44 (5): 726-42, 2000 Sep-Oct.  [PUBMED Abstract]