Use These Methods to Effectively Screen for Oral Cancer

Squamous cell carcinoma (SCC) is the 6^th most common malignancy in the world. Classical SCC carries a 5-year survival rate of approximately 55%. As described by Dr. Mark Lingen, DDS, PhD, at the ADA’s 2016 meeting in Denver, CO, the treatment plan for SCC must include early detection and improved modalities for prognostication and prevention, affording the greatest chance of survival for the patient. Dr. Lingen gave his presentation on Thursday, October 20 at the conference.

Screening

Performing patient screening is the backbone of early detection, Dr. Lingen said. Screening tests are not diagnostic tools, however. Additionally, oral cancer screening is not a stand-alone test. It is part of the dentist’s comprehensive exam, including both visual and physical or tactile components, used to identify any abnormalities or pathologies of the oral and/or maxillofacial region. A typical medical education does not teach comprehensive oral pathology. It is left to dentist to take sole responsibility for monitoring the oral mucosa of his/her patients.

Screening Methods

The table below highlights additional methods currently available to assist in detection of oral cancers. All methods listed are to be used in conjunction with the visual/physical exam. The devices below are “cleared for marketing” via the FDA 501(k) program. This program is for noninvasive devices and requires the device to demonstrate safety, but does not establish efficacy.

Screening Technique

Pros

Cons

Brush Cytology (scrape cells from mucosa, place on a slide, send out for analyzation)

• Useful for individuals with multiple lesions
• Useful for patients unlikely to be compliant with recommended follow-up

• Used inappropriately
• Cells seen out of context
• Result not definitive
• Visual based

Tissue Reflectance (Patient rinse with acetic acid, use light to evaluate lesions)

• FDA 501(k) clearance
• Capable of seeing lesions not seen with incandescent light

• Low degree of specificity

Tissue Autofluorescence (wavelength of light shone into mouth, looking for loss of autofluorescence)

• FDA 501(k) clearance
• May help to define surgical markers
• Capable of seeing lesions not seen with incandescent light

• May detect a range of mucosal abnormalities
• May not be generalizable
• Low degree of specificity
• Clinically relevant now distractors recognized

Reflectance and Autofluorescence (combination of the two individual components)

Salivary Diagnostics- HPV (saliva based HPV testing)

• Helps identify presence of HPV
• Helps decide how to treat patient

• Unknown specificity/sensitivity
• Unclear if disease is acute or chronic
• Unclear if HPV DNA is “episomal or integrated”

Salivary Diagnostics- Other (genetic markers, RNA/DNA, or proteins in the saliva)

• Easy sample collection

• Proteins tested may occur naturally in the body for other reasons
• Unknown specificity and sensitivity

A note about HPV

Oral cavity SCC (OSCC) is secondary to chronic exposure of tobacco and alcohol. While the epidemic of oropharyngeal SCC is secondary to HPV-16. According to the CDC, one percent of the population has HPV-16 in their saliva. However, only 35,000 new cases of HPV associated malignancy occur each year. This is because upward of 95% of infections are cleared from the body. Therefore, screening is rather tricky. The concern with the salivary diagnostic tests for HPV, is the interpretation of a positive test. As of now, the understanding of the natural history of HPV is low. More clinical data is needed to help guide dentists in the use of HPV salivary diagnostic tests.

Summary

There are a multitude of adjunctive therapies available to dentists to help screen and prevent progression of oral cancers. The dentist will need to clinically evaluate whether or not a test/device will help to determine the clinical course of action for his/her patient. The point to be stressed however, is that no matter the modality, early detection and prevention of oral cancers is key to patient survival.