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Systems detects 'a few' more false negatives
The Papnet automated Pap smear screening system can be effective in detecting false negatives, but it is far from a panacea and is fairly expensive, according to recent research.
The most comprehensive research regarding Papnet comes from the department of cellular pathology at the Armed Forces Institute of Pathology in Washington, DC. Timothy O'Leary, MD, PhD, and others at the institute studied the effectiveness of the Papnet system and concluded that "Papnet-assisted rescreening identified a few more cases of [abnormal cells] than did manual rescreening, but at a relatively high cost."1
O'Leary tested the Papnet system by using 5,478 Pap smears obtained from Air Force service members and their dependents, all between the ages of 12 and 88. The smears had been identified as "within normal limits" or having "benign changes" by cytotechnologists. All of the Pap smears were rescreened with the Papnet system, and those indicated as having suspicious cells were reviewed by a panel of three cytotechnologists and three pathologists.
The Papnet screening identified 1,614 slides requiring additional review, 29% of the total. Further review by the panel determined that 448, 8% of the total number, had possibly abnormal cells. Five of those smears were reclassified as atypical squamous cells of undetermined significance (ASCUS), and one was reclassified as atypical glandular cells of undetermined significance (AGUS). No additional squamous intraepithelial neoplasia was identified in the smears, and the patient with AGUS was diagnosed as having a low-grade squamous intraepithelial neoplasia.
Using the total costs of rescreening negative smears vs. the number of ultimate diagnoses, O'Leary determined that the costs were $5,825 to $33,781 for each additional ASCUS or AGUS diagnosis uncovered with the Papnet system. A cost of $17,475 to $101,343 was estimated for each case of low-grade squamous intraepithelial neoplasia identified by Papnet rescreening.
The researchers suggest that "strategies aimed at increasing the number of women screened, particularly among those who have not had a Pap smear, are likely to be much more cost-effective than computer-assisted rescreening to reduce cervical cancer morbidity and mortality."
A report from ECRI, the nonprofit health care device analyst in Plymouth Meeting, PA, underscores the point that Papnet automated screening leaves many questions unanswered for risk managers.2 The well-respected research organization notes that automated screens can't solve all problems associated with Pap smears and are not a mandatory part of any cancer screening program.
In addition to questions about the overall technical efficacy of automated screens, ECRI addresses some thorny legal issues that can occur when clinicians consider whether to adopt newly available technology. In the case of automated Pap smear screening, ECRI says there may be a dilemma when pathologists inform referring clinicians of the availability of automated screening.
"Predictably, clinicians, upon receiving such information from the pathologist, might be concerned about their own risk of liability should they fail to inform the patient," ECRI writes. "Patholo gists, of course, must weigh this potentially negative influence on the referral relationship against the potentially positive influence on liability exposure. Although it is unclear whether clinicians (mainly gynecologists and family practitioners) have a duty to inform patients of the newly available technologies, some attorneys have suggested that clinicians' legal exposure is unlikely to be altered by pathologists' actions in this regard."
ECRI suggests that liability risks associated with Pap smears could be reduced significantly by paying close attention to the way Pap smear slides are handled within facilities. Exposure can be increased if the slides are lost or damaged in transit, for instance, making them unavailable for screening or rescreening. ECRI suggests these steps to reduce that risk and other legal exposures:
o Ensure your staff have a specific protocol for packaging and shipping slides in a way that prevents breakage. Document custody of the slides while en route. Discourage patients from transporting their own Pap smear slides, but if they insist, document that you have transferred responsibility for the slides' safekeeping to the patients.
o Remind pathologists, technicians, pathology residents, and other lab workers to seek advice from your risk management department before sending any Pap smear slides that have been requested for legal reasons. Since it is sometimes extremely difficult to get the slides back once they have been turned over to someone else, you do not want staff to send them out automatically when requested. You may decide to contest a subpoena or require investigators to view the slides on your premises, for instance. At a minimum, you should require the other to party be responsible for any damage or spoliation of evidence.
o Educate staff about the difference between altering original reports and filing an amended report once new evidence is in hand. An amended report to an original Pap smear report may be appropriate after a slide is rescreened, but the first report should never be altered. Instruct staff to contact the risk manager if the amended report was prompted in any way by legal action or if the amended report was prompted by a medical review but might lead to legal action.
1. O'Leary TJ, Tellado M, Buckner S, et al. Papnet-assisted rescreening of cervical smears: Cost and accuracy compared with a 100% manual rescreening strategy. JAMA 1998; 279:235-238.
2. ECRI. Pap smears. Healthcare Risk Control 1998; March:1-23.