Inspecting the cervix with a bright light technology called speculoscopy directly after a Pap smear may detect more cervical lesions than the Pap test alone, according to a new review of studies about the procedure.
But the higher detection rates come at a cost: More potentially cancerous lesions will be caught with the combination of technologies, but the process also increases the risk of “false positives,” or cells wrongly identified as lesions, according to the researchers. Their review was published by ECRI, a nonprofit health services research agency that produces systematic evidence reviews on medical devices, drugs, biotechnologies and procedures.
The addition of speculoscopy to regular Pap smear screening helped detect an additional 42 to 62 lesions per 1,000 patients screened, but the technology also increased the number of false positives from 55 to 111 for each 1,000 patients screened.
“The trade-off between finding more lesions and more false positives is typical of diagnostic technologies,” says ECRI study author Charles Turkelson. “At issue with speculoscopy is that determining its exact clinical significance, as well as its place among screening tools, awaits further study.”
The ECRI report identified only three studies that compared speculoscopy and Pap smear with Pap smear alone, so the available evidence about speculoscopy remains “weak,” it concludes.
Speculoscopy is not covered by Medicare, and the study authors found few private medical insurers who mentioned the procedure in their policies. Those insurers who did mention the procedure did not cover it, calling it “investigational.”
None of the available speculoscopy studies discuss whether the technology decreases the likelihood of developing cervical cancer or prevents outcomes like hysterectomies or cancer-related deaths.
Speculoscopy involves washing the cervix with a diluted acid solution after a traditional Pap smear and then inspecting the cervix with a special disposable blue-white light called a Speculiteฎ, made by the Trylon Corporation.
Using a low magnification lens provided with the light, a physician uses the light to detect potential lesions that have been highlighted with the help of the acid wash. The combined procedures take about two to three minutes to complete.
In a Pap smear, cells are scraped from the cervix and examined microscopically for signs of cancer. Speculoscopy is meant to work hand in hand with Pap smears, not replace them entirely, the authors note.
“The Pap smear has been one of the most effective mass screening tools for detection of non-invasive forms of cervical lesions during the past 60 years,” they say.
However, human error can creep in when cervical cells are collected and analyzed for the Pap smear, the authors say, Also, some women do not shed abnormal cervical cells, making it hard to detect any lesions by Pap smear alone.
The three studies analyzed by ECRI included 3,645 patients studied between 1993 and 1998. One other study identified by the ECRI researchers compared the cost-effectiveness of an annual Pap smear versus a speculoscopy plus Pap smear procedure every two years.
Although the combination procedure seemed to slightly reduce the cost of follow-up screenings and tests, the comparison “should be made cautiously” because the two procedures were compared over different time frames, the ECRI authors say.
“An important question that has not been addressed in any study to date is how speculoscopy compares with competing technologies, such as thin-layer Pap smear preparation or automated slide screening. These are becoming accepted aspects of cervical cancer screening, such that fewer and fewer clinicians and labs are treating Pap smear slides using traditional methods,” the report authors explain.
More than 10,000 cases of cervical cancer will be diagnosed in the United States in 2004, with nearly 4,000 women dying of the disease. Cervical cancer is more common among black and Hispanic women than white women.
ECRI is a nonprofit international health services research agency that provides information and technical assistance to the health care community.
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