A well-designed campaign to educate the profession and the public about oral cancer diagnosis could be important in decreasing morbidity and mortality associated with this terrible disease. We are concerned, however, about the current promotion [which concludes this month] sponsored by the American Dental Association and underwritten by a private corporation that touts a "painless" detection of oral cancer.1
Several studies have demonstrated the effectiveness of oral screening examinations in detecting precancerous and cancerous oral lesions.2–4 Failure to perform thorough head, neck and oral examinations will undoubtedly allow the disease to progress to more advanced states,5 and each of us has firsthand knowledge of many patients whose disease went undiagnosed for this reason.
We believe that the public and profession would be better served by emphasizing examination and early definitive diagnosis rather than by advertising an industry-proposed proprietary technique that has not been independently verified. Perhaps a critical review of "painless" testing for oral cancer would be enlightening for readers of this journal.
The "new" brush biopsy technique in question is a variation of the cytologic smear technique, and thus has the strengths and weaknesses inherent in cytology. By its very nature, specimen acquisition disrupts the cellular orientation found in situ, and must, of course, be followed by scalpel biopsy to obtain definitive diagnosis.
Proponents of this methodology suggest that it represents an advance in cancer diagnosis, an assertion that we do not believe is supported by data. Although several articles about it have appeared in peer-reviewed literature, to our knowledge no publication has been authored by an individual not associated with the company that offers the service.6–10 In addition, design flaws in the study and selective emphasis on outcomes favorable to the company suggest that the reported findings should be viewed cautiously.
The study design for the trial purporting to show the efficacy of brush biopsy7 has several serious flaws. The authors advocate the "brush biopsy" as a screening tool, and compare it favorably to both Pap smears and mammography. This comparison is inappropriate, however, since Pap smears and mammography are screening tests of a population without known disease, and the brush biopsy technique is recommended for visible clinical abnormalities.
Screening tools are used to find unrecognized disease (a breast mass, for instance), while diagnostic tests analyze an abnormality known to be present (histologic examination of a mucosal ulcer, for example). Because mucosal abnormalities are clinically recognizable, screening is unnecessary; a test that confirms what is clinically visible, but cannot provide a more definitive diagnosis, is likewise without merit. Fear of performing a scalpel biopsy, or inadequate training in its performance, should not be construed as an indication to perform other tests that will further delay completion of the definitive diagnostic test.
Although reported as a "multicenter clinical trial," the study failed to meet that constraint because all cytology specimens were analyzed at a single site: the company laboratories. A stated goal of the study was comparison of the new technique to the "gold standard" scalpel biopsy, yet scalpel biopsies were not performed in nearly two-thirds of patients tested. This failure makes analysis of sensitivity and specificity data incomplete.
In addition, the authors reported that 7 percent of specimens were nondiagnostic, a much higher incidence than commonly seen with scalpel biopsy.
Of greater concern perhaps are unsubstantiated claims and benefits for the technique. While the campaign revolves around the term "painless," pain was not tested in the study. Since the technique is expected to result in pinpoint bleeding as the full thickness of epithelium is disrupted in specimen acquisition, some discomfort might be anticipated. Whether that discomfort is greater than the administration of local anesthesia that accompanies scalpel biopsy is unclear, since no comparison was made.
Neither did the study show that the technique provides an advantage to earlier diagnosis. The case can, in fact, be made that it delays initial diagnosis. Cytologic methodologies cannot presently provide a definitive diagnosis of cancer, and must be followed by scalpel biopsy for tissue diagnosis.11–13
Waiting seven to 10 days for cytology results before proceeding to that definitive diagnosis, especially for a patient suspected to have cancer, is insensitive to the patient and serves no pressing treatment purpose. We suspect that even the proponents of brush biopsy would prefer to know their diagnosis sooner rather than later so that definitive treatment could be instituted.
We are aware that the billboard campaign currently under way uses a young, attractive model with a precancerous lesion photographically superimposed on her tongue.1 We are also aware of the disclaimer by the ADA that no specific technique is advocated, yet the published "painless" slogan is the same one used in [the company’s] advertising, and at least some ADA component societies believe it is the "test being promoted by the ADA."14
It seems to us that no matter what "focus groups" were employed to design the promotion, using such an atypical cancer presentation is a scare tactic that should have no place in a public education campaign, and industry subsidies with even the hint of impropriety should be avoided.
Wouldn’t both dentists and patients be better served by advocating improved screening using diagnostic techniques that enable earlier and more effective treatment?
TOP
REFERENCES
