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Noninvasive oral cancer test to be soon available

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drsnehamaheshwari's picture
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A new, noninvasive cytology test for oral cancer, aimed at "watch and wait" lesions,  ClearPrep OC, is being offered to dentists. The test is less expensive than biopsies and less frightening for patients, according to Resolution Biomedical, the company that is commercializing it.
The chairside oral cancer test -- which can be ordered directly from the company -- is designed to be a diagnostic option for assessing lesions when a biopsy is not warranted or the patient fears getting a biopsy, according to Donald Williams, MD, chief medical officer of Resolution Biomedical.
The test involves a cyto-brush sampling method that measures gross changes in the nuclear DNA content of oral epithelial cells, providing information about the precancerous or cancerous state of a lesion, the company explained. The samples are sent to medical testing labs, and the report is sent to the dentist within four to five days, the same time frame as biopsies. Dentists send the samples to the company, which prepares the slides and sends them to labs, which prepare a diagnostic report for the dentists.
"It's a way to triage patients where something may be suspicious but the patient is balking about getting a biopsy," said Dr. Williams. "It could be leukoplakia lesions or thrush instead of an indication of a neoplasm. It rules out biopsies without an invasive process."
When dentists refer patients to periodontists to get biopsies of suspicious lesions, many patients don't follow through on the recommendation because they find it a daunting procedure, Dr. Williams noted.
"Some patients think, 'I've had this for years and it hasn't killed me, so I don't want to be biopsied,' " he said. "It's kind of frightening to say you're going to have a piece of meat cut out of your mouth."
The most logical application is for worrisome lesions that are likely benign, Dr. Williams said.
 
Ongoing clinical trial
Resolution Biomedical conducted about five validation studies of the ClearPrep OC test in general practices over six months, Dr. Williams said. It is now being tested with Southern California dentists.
In addition, the test is in the second phase of a trial study with cancer patients in the City of Hope cancer research hospital in Duarte, CA. ClearPrep OC and saliva samples will be taken, and p16 stains will be done on the biopsy specimens. All the modalities then will be combined before a blind match is done. The company plans to do a joint publication based on the results with the University of California, Los Angeles, Dr. Williams said.
The test was primarily designed for gynecologic cytology pap tests, but Resolution Biomedical realized it also had potential to detect oral cancer.
The company does not plan on doing an official launch of the product, which has no marketing restrictions since nongynecologic cytology tests are an established medical practice, according to Dr. Williams. As a result, the test does not require U.S. Food and Drug Administration clearance or need to be Clinical Laboratory Improvement Amendments (CLIA)-certified, he said.
While the test is being provided for free to dentists, patients and labs pay $60 to $125 -- much less than biopsies, which range from $400 to $500, according to Dr. Williams. It is usually covered by insurance, and dentists can charge a collection fee for the process, including interpreting the final report, according to Dr. Williams. Company revenues will be derived from the testing labs it uses for analysis.
"Biopsies are invasive, expensive, and painful," said company CEO Mike Friedl. "This is an intermediate way to rule out stuff while you're still at the dentist rather than going to a specialist."
The test is especially suitable if the condition is simply a treatable condition, such as a fungal change, and doesn't require a trip to see a specialist, Friedl noted. Since the human papillomavirus (HPV) is now associated with many oral cancers, the company tests for it if the sample shows any degree of atypism.
Sol Silverman Jr., DDS, a professor of oral medicine in the University of California, San Francisco (UCSF) School of Dentistry and head of one of the oral medicine clinics at UCSF, called the ClearPrep test a good adjunctive diagnostic technique.

"Cytology has been around a long time, and it's very high-quality," said Dr. Silverman. "Any technique that will accelerate the recognition of dysplasia is important. Early detection is still our best approach to good survival results. 

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Noninvasive oral cancer test to be soon available
A U.S. government-backed panel issued a statement today saying that there is not enough published evidence to recommend for or against screening for oral cancer.
Evidence is lacking on whether screening can accurately detect oral cancer and if earlier treatment of cancers found during those tests improves long-term health, according to the U.S. Preventive Services Task Force (USPSTF).
Their draft recommendation statement applies to people who do not have any signs or symptoms of oral cancer and is meant for primary care professionals screening for oral cancer. It is not a recommendation about the practices of dentists and oral health professionals, the panel noted.
The task force an independent volunteer panel of national experts in prevention and evidence-based medicine reviewed the current literature and found:
-          Inadequate evidence that the oral screening examination accurately detects oral cancer
-          Inadequate evidence that screening for oral cancer and treatment of screen-detected oral cancer improves morbidity or mortality
-          Inadequate evidence on the harms of screening; no study reported on harms from the screening test or from false-positive or false-negative test results
Seven studies (n = 49,120) examined the performance characteristics of the oral screening examination. These studies were generally conducted in settings with an increased incidence of and mortality from oral cancer (India, Taiwan) compared with U.S. rates, the panel reported. The studies also had considerable heterogeneity and demonstrated great variation in test performance characteristics. Across the seven studies, sensitivity for oral cancer or potentially malignant disorders ranged from 18% to 94.3% and specificity from 54% to 99.9%. The positive predictive value ranged from 17% to 86.6% and the negative predictive value from 73% to 99.3%.
Two studies in the U.K. looked at oral examinations performed by general dentists among older adults (age 40 years or older) at increased risk because of alcohol and tobacco use and a mixed sample with unknown risk factors. The dental examination in the high-risk sample (n = 2,027) showed a sensitivity of 74%, a specificity of 99%, and a positive predictive value of 67%, while the study of patients with unknown risk factors found a sensitivity of 71%, a specificity of 99%, and a positive predictive value of 86%.
Although the patients in the U.K. study may be similar to the U.S. population, the results of these studies were limited by an imperfect reference standard, by combining the detection of potentially malignant disorders with oral cancer and an unclear delineation of high-risk status, according to the USPSTF.

“The evidence shows that it is difficult to detect oral cancer and that the evidence is not clear whether oral cancer screening improves long-term health outcomes among the general adult population or among high-risk groups,” stated task force member Jessica Herzstein, MD, MPH, said in a news release. “We need more high-quality research on whether screening tests can accurately detect oral cancer and if screening adults for oral cancer in primary care settings improves health outcomes.” 

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Noninvasive oral cancer test to be soon available
Endoscopic narrow-band imaging (NBI) is more effective than broadband white light (BWL) imaging in detecting high-grade dysplasia and carcinomatous lesions in oral leukoplakia, according to a new study in the International Journal of Oral & Maxillofacial Surgery.
For the study, a team of researchers from Taiwan investigated the clinical efficacy of using BWL to observe morphologic appearance, NBI to observe intraepithelial microvasculature, and both to detection high-grade dysplasia and carcinoma in oral leukoplakia. They wanted to see if, when used to assess oral leukoplakia, NBI can provide more information than the traditional classification under BWL.
"Narrow-band imaging is an innovative optical technology that enhances the contours and patterns of vessels, or intraepithelial microvasculature, in the surface of mucosa by employing the characteristics of the light spectrum," the study authors wrote.
They reviewed the records of 317 patients at Chang Gun Memorial Hospital who were newly diagnosed with oral leukoplakia between April 2009 and August 2011, were examined using flexible endoscopy with BWL and NBI, and underwent biopsies or surgical excision for the leukoplakia.
The optical exams were conducted using NBI endoscopes, light sources, and a central video system from Olympus Medical Systems. A button on the control section of the video-endoscope allowed for switching between the BWL and NBI views.
"The examinations were first conducted using BWL illumination in a wide view to observe the entire lesions and its surrounding mucosa," the researchers explained. "The same procedure was performed under NBI illumination for detailed analysis of the appearance of the intraepithelial microvasculature and screening of random sites of normal mucosa."
The resulting images were then analyzed and compared with the histopathologic finding for each patient. The clinical morphologic appearance under BWL was analyzed first, including homogeneous and nonhomogeneous leukoplakia. The latter was categorized as the verrucous, nodular, or speckled type. Imaging analysis of the NBI features (microvascular organization and intraepithelial papillary capillary loop) was conducted based on the intraepithelial microvasculature patterns of the oral mucosa.
Sensitivity, specificity, false positives
Each patient's chart records were reviewed, including their demographic data, lesion location, homogeneous/nonhomogeneous leukoplakia, vascular architecture, and histopathology. Using the histopathologic findings, the researchers then determined any correlation between pathology and imaging by BWL and NBI by assessing the sensitivity, specificity, positive and negative predictive values, accuracy, and false-positive and false-negative percentage in detecting high-grade dysplasia, carcinoma in situ, and invasive carcinoma (HGD/Tis/CA). They also compared traditional classification of leukoplakia based on morphological appearance using BWL and pattern of intraepithelial microvasculature using NBI.
"Observing oral leukoplakia with the naked eye is not difficult, but the reddish component of nonhomogeneous leukoplakia, especially the speckled type, may not be prominent and may be neglected or mistaken for homogeneous leukoplakia," the researchers noted.
Using an endoscope with improved brightness, light distribution, high-resolution images with better color reproduction capability, and larger display size, "white plaque lesions can be examined at close range, in detail, to reduce this inaccuracy," they added.
Among the 317 patients analyzed in this study, the researchers found that using NBI classification based on the intraepithelial microvascular patterns was significantly better than traditional classification in detecting HGD/Tis/CA (p < 0.001). Although the sensitivity and negative predictive value of traditional classification were better than NBI (96.30% and 97.85% versus 87.04% and 97.23%), "the specificity and diagnostic accuracy of the former are much poorer" (60.08% and 66.25% versus 93.54% and 92.43%). In addition, the false-positive rate of traditional classification in detecting HGD/Tis/CA of oral leukoplakia is higher than NBI classification (39.92% versus 6.46%), they noted.
Comparison between the traditional BWL classification and NBI classification for detecting HGD/Tis/CA of oral leukoplakia was significant (p < 0.001), while comparison between the traditional BWL classification and combined BWL and NBI classification was not (p = 0.564). However, comparison between the NBI classification and combine BWL and NBI classification was significant (p < 0.001).
"The NBI classification based on intraepithelial microvascular patterns is significantly better at detecting HGD/Tis/CA lesions in oral leukoplakia than the traditional BWL classification based on the morphological appearance," the study authors wrote. "As endoscopy with NBI can provide useful data regarding dysplastic or carcinomatous changes, it is a promising tool in detecting HGD/Tis/CA of oral leukoplakia."
This is not the first study the research team has published demonstrating the efficacy of endoscopy and NBI to evaluate oral leukoplakia. A study published last year in Head & Neck (July 2012, Vol. 34:7, pp. 1015-1022) found that the correlation between intraepithelium papillary capillary loop classification and stepwise increased severity of pathology was significantly better using NBI than BWL images (p < 0.001).
"Flexible endoscopy can enhance detailed inspection of oral cavity mucosa and can be a powerful tool for examining oral leukoplakia," the authors concluded.

  

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Noninvasive oral cancer test to be soon available

More effective detection and diagnosis of oral cancer could result from an advance in noninvasive imaging of epithelial tissue, according to a study in Journal of Biomedical Optics (March 19, 2013).

Researchers from Texas A&M University in College Station used confocal microscopy together with fluorescence lifetime imaging (FLIM) to noninvasively evaluate structural changes in tissue and molecular changes that take place on a cellular and tissue level. These morphological and biochemical changes are key factors in determining if tissue is precancerous or cancerous, the researchers stated in a press release.

Visually determining areas in the oral cavity that warrant a biopsy can be difficult because a patient's mouth can manifest large, heterogeneous lesions that may be both benign and precancerous and indistinguishable by eye, they noted. Their imaging technique is designed to more precisely guide doctors to the troubled areas of a patient's mouth through the use of optical images.

FLIM enables researchers to image large areas of oral tissue with ultraviolet light in a manner that shows signs of the molecular changes associated with precancer and cancer, revealing potential trouble areas. Confocal microscopy is a single-point measurement (about 0.5 mm in this case) with a high sensitivity to provide information about the morphological features of tissue.

By combining the two imaging techniques, FLIM can act as a guide for the confocal microscopy utilized in this approach.

So far, the results have been promising, according to the researchers. They have been able to combine the two systems so that the macroscopic and microscopic images produced from each technology can be coregistered.

 

The researchers are working to obtain more data points before claiming the sensitivity and specificity required from a system such as this. The researchers are in the process of analyzing additional data from a hamster model of oral cancer and working with the Baylor College of Dentistry in Dallas to evaluate the imaging system on samples of human oral biopsy tissue.

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Noninvasive oral cancer test to be soon available

Most imaging modalities are diagnostically accurate in detecting mandibular bone tissue invasion in patients with oral squamous cell carcinoma (SCC), according to a study in Dentomaxillofacial Radiology (June 2013, Vol. 42:6).

Researchers from Universidad Austral de Chile conducted a systematic review of studies in Medline, SciELO, and ScienceDirect, published between 1960 and 2012 in English, Spanish, or German, that compared detection of mandibular bone tissue invasion via different imaging tests against a histopathology reference standard. Sensitivity and specificity data were extracted from each study; the outcome measure was diagnostic accuracy.

They found 338 articles, of which only five met the inclusion criteria. Tests included were computed tomography (CT) (four articles), MRI (four articles), panoramic radiography (one article), positron emission tomography (PET)/CT (one article), and cone-beam CT (CBCT) (one article).

The quality of articles was low to moderate, the researchers noted, but the evidence showed that all tests have a high diagnostic accuracy for detecting mandibular bone tissue invasion by SCC, with sensitivity values of 94% (MRI), 91% (cone-beam CT), 83% (CT), and 55% (panoramic radiography), and specificity values of 100% (CT, MRI, CBCT), 97% (PET/CT), and 91.7% (panoramic radiography).

While available evidence is "scarce," the researchers concluded, "it is consistently shown that current imaging methods give a moderate to high diagnostic accuracy for the detection of mandibular bone tissue invasion by SCC."

 

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Noninvasive oral cancer test to be soon available

A new genetic test accurately and consistently diagnoses benign nodules on the thyroid gland, according to a study presented June 22 at the annual meeting of the Endocrine Society.

The problem with the current screening method -- typically a fine-needle aspirate biopsy -- is that in one-fifth to one-fourth of them the results are unclear, according to the study authors, from Pontifical Catholic University of Chile. In addition to causing anxiety among patients, inconclusive tests lead to repeated tests to rule out cancer, or even to surgery, given that cancer is present in about 25% of inconclusive cases. As a result, 3 out of 4 patients have unnecessary surgery, leading to rising treatment costs and the risk of possible complications related to unnecessary medical procedures.

To develop their gene signature test, the investigators conducted a literature search to identify 18 genes associated with thyroid cancer. They then selected 10 of these genes to develop a computer program that detects the presence of cancer in thyroid nodules. Using a sensitive DNA-amplifying test called polymerase chain reaction, they tested samples of thyroid nodules from 300 patients.

The test is potentially useful to identify patients who do not require surgery, according to researchers. The test accurately identified benign nodules in nearly all samples analyzed. Specifically, the test differentiated between cancerous and noncancerous tissue in 96% of thyroid samples.

More than 60,000 cases of thyroid cancer will be diagnosed in the U.S. this year and about 1,850 related deaths will occur, according to estimates from the American Cancer Society. Of these, more than 45,000 will occur in women, who develop the disease more often than men.

 

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