United Kingdom Department of Health report evaluating HPV/LBC cervical screening pilot studies
Cytopathology sessions at CAP ’03
Nancy A. Young, MD
The United Kingdom Department of Health fully converted to liquid-based cytology in three sites in England as part of a pilot study to evaluate its effect and costs. The study also used HPV triage in women with mild/borderline smears to determine the timing of referral to colposcopy during a 12-month period. Although both ThinPrep and Surepath were used and differences between the two were noted, the report says the studies were not designed to be a formal comparison. The UK report (by S.M. Moss, A. Gray, and E. Henstock) is an interim evaluation of the first six months of the pilot studies, and the full report is posted at www. cancerscreening.nhs.uk/ cervical/ lbc- pilot- evaluation.pdf. More detailed information will be in the final report, which will also include an evaluation of the costs and effects of HPV triage. Cytyc and Tripath Imaging have comments on this report on their Web sites as well.
In summary, the report says the introduction of liquid-based cytology resulted in a clear reduction in the reported rate of inadequate smears, from nine percent to one to two percent, although changes in reporting of smears lacking evidence of transformation zone sampling may have had an effect on the inadequacy rate. There was a reduction in the rate of smears reported as showing glandular neoplasia, but it was not clear how the lesions were being reported now (such as negative or high-grade squamous dysplasia), and the cytological reasons and implications are still under investigation. The provisional positive predictive value for high-grade squamous lesions for all study sites combined suggest that sensitivity for HSIL is no lower with liquid-based cytology than conventional cytology.
The total cost to the health care system was analyzed, including the time it took to take the smear in the primary care setting, transportation, storage, training, laboratory preparation, and laboratory productivity. They found that, overall, using liquid-based cytology results in a small lifetime cost saving to the total health care system as compared with conventional cytology, though these savings may not be passed down to the laboratory.
The decrease in the proportion of inadequate smears that needed to be repeated and the decrease in the primary care costs of smear taking and administration seemed to be the major factors behind the cost reduction. Productivity of laboratories increased with liquid-based cytology. The study found that nine percent more slides per hour could be screened by the primary screener. In general, smear takers in primary care and laboratory staff were pleased with the implementation of liquid-based cytology.
Dr. Young, a member of the CAPCytopathology Committee, is in the Department of Pathology, Fox Chase Cancer Center, Philadelphia.
Pap test screening and glandular cervical cancers
Emily E. Volk, MD
Historically, the dramatic decreases in the incidence of cervical cancer credited to the widespread adoption of the Pap smear have been related primarily to the decreased incidence and mortality of squamous carcinomas. Subsequently, glandular carcinomas of the cervix have begun to represent a larger percentage of potentially life-threatening cervical lesions. Whether Pap smear screening has any effect on the incidence and mortality of glandular cervical cancers has not been clearly established.
Dr. Walter Kinney and collegues have attempted in a recent article to address the question of whether Pap smear screening had any effect on the stage and mortality of glandular cervical cancers (Acta Cytol. 2003;47:167-171.) They performed a retrospective review of 169 women diagnosed with invasive adenocarcinoma or adenosquamous carcinoma from 1988 to 1994. They found that patients with invasive glandular carcinomas identified at the time of screening were diagnosed at an earlier stage than those who were not. They also found that these patients had a lower disease-specific mortality than those not detected by screening. This is in contrast to previous studies in which the epidemiologic evidence would suggest that if a screening effect exists at all, it is limited.
The findings of this study suggest that Pap smears may have a role in screening patients for glandular lesions of the cervix. Further larger studies are necessary to confirm these findings. Certainly, if the conclusions of this study are proved correct, further efforts will be necessary to establish optimal techniques and screening intervals in order to best detect these glandular lesions early.
Dr. Volk, a member of the Cytopathology Committee, is staff pathologist at William Beaumont Hospital, Troy, Mich.