Screening with PapNet is better, but cost/benefit ratio questioned
Encouraging women to get Pap smears is the larger issue
Is computer technology always superior in providing the best health care in terms of cost and meeting patients' needs? Women's health center managers face this issue with PapNet, a computerized device for rescreening Pap smears. Although PapNet shows a higher accuracy rate in detecting abnormal cervical cells, a recent study says it's only slightly better yet costs 20 to 30 times more than traditional manual scanning, according to an article in the Jan. 21, 1998, Journal of the American Medical Association. For the most part, insurance companies don't cover PapNet, so patients bear the extra cost.
Timothy O'Leary, MD, PhD, pathologist and chairman of the department of cellular pathologists at the Armed Forces Institute of Pathology in Washington, DC, conducted research on PapNet's effectiveness. O'Leary says the more expensive PapNet isn't necessary. The greater issue in detecting cervical cancer is not the rescreening process but getting screened in the first place. "The best cancer prevention is getting a Pap smear regularly," he says, adding that a common misconception is that cervical cancer most often results from misread Pap smears. "That does happen at times, due to human error, but far more cases of cervical cancer are due to a lack of screening in the first place."
Eighty percent of cervical cancers are diagnosed in women who haven't had Pap smears in the past five years, O'Leary says. One-third of all women aren't screened regularly. "Most patients who are not getting screened are over 50 years old, and most new cancers occur in women over 50. So there's a greater need to address patients who avoid Pap smears altogether." (See tips on making the test easier for women, p. 60.) He suggests women's health center managers consider the most important aspects of screening women:
· Regular screening as infrequently as every three years will reduce cancer by as much as 90%.
· An adequate smear by a nurse practitioner or physician is critical. "All labs have received smears that are inadequate or marginally adequate," he says.
· The quality of the lab, which should be accred ited by the College of American Pathologists in Chicago, is critical.
Study shows method expensive
Rescreening is another matter altogether. O'Leary studied 5,478 pap smears and compared manual rescreening with PapNet to determine the cost-effectiveness of the computerized technology in relation to its accuracy.
"We wanted to find out what PapNet costs to catch additional cases above and beyond manual rescreening," he says. "We did a double-rescreen manually before using PapNet, and we did catch a few cases that were missed on the manual rescreen. But you have to look at an awful lot of cases to do that."
Results of the study showed that PapNet found one more abnormal smear in every 913 cases. "Our analysis and observation was that PapNet was expensive, based on cost assumptions that reflected our costs," he explains. "With PapNet, we did find a few atypical cells of undetermined significance but could not tell for sure if they were pre-cancerous, and it was very expensive to do so." Manual rescreening costs about $3 per slide; PapNet costs about $50 per slide.
O'Leary's study was based entirely on price associated with computer-assisted rescreening - not on PapNet's overall effectiveness. "PapNet is safe and effective, but that doesn't mean that the more expensive rescreening method is the best. It's OK. If PapNet becomes less expensive, it would make a lot of sense to use."
Neuromedical Systems in Suffern, NY, which manufactures PapNet, obviously disagrees with those findings. The manufacturer claims, first of all, that O'Leary had a "skewed" population in his study of younger, healthier military women vs. the general population. O'Leary counters that his group represented the norm.
"We present in the study what our distribution was: 12- to 88-year-old women, including those in the military, independents, and retirees. Yes, this group has good access to regular health care and is not economically disadvantaged," O'Leary says. "But is that a material issue? I honestly don't know. All managed care patients have similar access to the health care my research group has. So, in that case, we have comparable systems.
"One thing I'm uncertain of, though, is the quality of the lab or gynecologists that patients have - there's an infinite variation out there."
Neuromedical Systems argues its product is worth the cost. "We've had 22 studies published on the favorable results of PapNet," says Andrew Panagy, the company's vice president of marketing and sales. (See selected references at end of article.) Responding to O'Leary's research, Panagy says, "Despite the double manual rescreening, PapNet still detected abnormalities. It's amazing PapNet found any at all."
Addressing the concern that PapNet wasn't worth the cost patients incur, Panagy says, "That's what used to be said about mammograms, but since they have helped detect breast cancer, patients' attitudes have changed about paying out-of-pocket for mammograms. Patients are willing to pay even if insurance doesn't cover PapNet because you can't put a dollar value on the life years gained."
In addition, Panagy says a growing number of insurance plans are covering PapNet rescreening. (See story on coverage by Blue Shield of Calif ornia, at right.) "For its accuracy, PapNet is cost-effective," he says, adding that Neuromedical Systems is seeking approval from the U.S. Food and Drug Administration for PapNet to be used as a primary screening method.
Let the patient decide
A recent study questions the cost-effectiveness of PapNet, saying manual screening is just as accurate for less cost. But some health care providers support PapNet and say ultimately it's up to the patient. "Who's determining to spend this money? It's the patients who should decide," says Brian Levitt, MD, OB/GYN at Perimeter OB/GYN Care in Decatur, GA, who was the first physician to use the PapNet technology in Georgia. Levitt says he gives each patient a consent form to accept or refuse PapNet.
"Although many insurance companies don't cover rescreening unless there's an abnormal result, most patients are willing to pay the $49," Levitt says.
Some women have three pap smears in a year, he says. "The first is abnormal, the next one is normal. They're not sure which to believe, so they have a third, going to a different doctor each time. Why shouldn't PapNet be available to them?"
Levitt says one in nine American women have breast cancer; four in 10 Americans develop cancer in their lifetime; and colon, ovarian, and breast cancer are related. "As a result, there are cancer-phobic patients, and they want peace of mind. Almost every single breast cancer patient I have says `yes' to PapNet because they feel that the additional cost is nothing compared to cancer."
The Armed Forces research, Levitt says, had the "best pathologists and cytologists in the world" reading the Pap smears vs. "normal, regular labs with a higher-risk population. If a lab is reading a slide on a Friday afternoon, there's going to be more individual observer error because they're tired," he maintains.
Levitt says PapNet is more accurate because the computer scans a slide and tags where the abnormal cells are located. "When a cytologist manually scans a slide, they don't look at every single cell. PapNet looks at every single cell [numbering roughly 300,000 on a slide], then selects the 25 most abnormal ones.
"Then, PapNet shows the cell size on half the computer screen vs. someone looking at small cells under a microscope, so the projection is much larger."
Levitt recommends PapNet especially for high-risk groups, such as women who have multiple sex partners, previous abnormal Pap smears, a history of venereal disease, a family history of cancer, an uncircumcised partner, or women who smoke.
Judith Petterson, MSN, certified perinatal nurse practitioner at Medical Group of Northern Nevada in Reno, agrees. "Women are reservoirs for infection, so it's critical to have a screening tool for more accuracy," she says. "What if a cytologist misses an abnormal smear two years in a row, so a patient forgoes a Pap smear the next year because she thinks there's no problem?"
Petterson says there are three variables in collecting a Pap smear:
· collecting a good sample;
· making sure it's not mixed up in the lab;
· having a knowledgeable cytologist read the sample.
If any one of them causes an error, it will alter a correct reading, she says, and PapNet serves as a check and balance. "I offer this as an option to all my patients because you don't have to be in an at-risk group to contract an abnormality. They understand it's an extra cost, but the patients who select PapNet feel it's worth it." In fact, the protocols for Pap screening should incorporate PapNet, she maintains.
Selected references
1. Koss LG, Sherman ME, Cohen MB, et al. Significant reduction in the rate of false negative cervical smears with neural network-based technology (PAPNET Testing System). Human Pathol 1997; 28:1,196-1,203.
2. Duggan MA, Brasher P. Paired comparison of manual and automated Pap test screening using the PAPNET system. Diag Cytopath 1997; 17:248-254.
3. Husain OAN, Kocjan G, Butler EB, McGloin JE. PAPNET: The human and other dimensions. Acta Cytol 1997; 41:1,439-1,444.
4. Ashfaq R, Saliger F, Solares B, et al. Evaluation of the PAPNET system for prescreening triage of cervicovaginal smears. Acta Cytol 1997: 41:1,058-1,064.
5. Sherman ME, Schiffman MH, Mango LJ, et al. Evaluation of PAPNET testing as an ancillary tool to clarify the status of the "atypical" cervical smear. Mod Pathol 1997; 10:564-571.
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