The Business of Saving Lives: Dentistry and The Fight Against Oral Cancer

Some data indicate that oral cancer diagnoses in the U.S. rose by 61 percent from 2011 to 2015.

Dentists, whether they realize it or not, are on the frontline of the war against cancer. With the prevalence of oral cancer on the rise, dentists are positioned to provide patients with critical diagnostic care. Suddenly, dentists find themselves not in the business of cavities and crowns, but saving potentially countless lives.

In the United States, oral cavity squamous cell carcinoma is the most common cause of malignancy in all head and neck cancers, accounting for about 90 percent of cancers that are diagnosed in this anatomical region.¹ It’s estimated that about 49,670 people in the U.S. will be diagnosed with a form of oral cancer in 2017. Worldwide, oral cancer is the sixth most common form of cancer², most often diagnosed in male patients and typically appearing after it has metastasized³.

Diagnosis of this form of cancer typically occurs about age 62, although slightly more than one-quarter of these types of cancers develop in younger patients³. Recently, there has been an increase in public awareness efforts regarding oral cancer and the role dentists play in screening for the disease.

“We’re in a place in history that is unique: Americans, in general, have never been more interested in their own health,” says Brian Hill, founder and executive director of The Oral Cancer Foundation. “The interest in cancer screenings has become a normal part of our lives, and things that we normally didn’t think about 20 years ago, we’re regularly getting screened for now.

“The good news is that the American public is receptive to screening. Our government is also realizing that treatment is way more expensive than early discovery. Right now, we have an audience that wants information.”

CANCER RATES ARE INCREASING

Since the mid-1970s, the incidence of oral cancer has increased about 15 percent⁵, with a 0.5 percent annual increase in positive diagnoses¹. According to some data, privately billed insurance claims in the U.S. related to oral cancer diagnoses rose by 61 percent from 2011 to 2015⁶.

“There are publications that show the rate of oral cancer — not oropharyngeal cancer – in young patients is increasing,” says Brian Schmidt, D.D.S., M.D., Ph.D., an ADA spokesperson. “It’s hard to get exact numbers on this, but it seems oral cancers are increasing. We don’t yet understand the etiology of this.”

The term “oral cancer” can be misleading since it is often used as a single diagnostic term when discussing all cancers of the head and neck. It is important to distinguish between true oral cancers — those occurring in the oral cavity on the tongue, gums, buccal mucosa, or floor of the mouth – and oropharyngeal cancers that occur on the soft palate, the base of tongue, and the tonsils¹. Squamous cell carcinoma can certainly develop in this region independently of any growth in the mouth itself^1,4.

A NEW CANCER RISK FACTOR

Infection with human papillomavirus (HPV) has recently emerged as a major risk factor for the development of oropharyngeal cancers.⁷ Most commonly, HPV infection is associated with squamous cell carcinoma of the tonsils and the base of the tongue². In the U.S., HPV infection has been shown to account for more than 60 percent of all oropharyngeal cancers¹.

There is now some debate over whether HPV infection could be a causative factor in the development of oral cavity squamous cell carcinomas. HPV colonization within the oral cavity can be identified in 2-8 percent of the healthy adult population, but studies suggest these infections typically resolve within a year.⁴ In individuals engaging in frequent high-risk oral sexual behavior, or those with weakened immune systems, HPV infections are more likely to persist and may be a critical factor for the development of HPV-related cancers⁴.

In the body, HPV infects basil epithelial cells and can remain latent within these tissues. Research has shown HPV can infect gingival tissue, invading the periodontal pocket where basil cells are exposed to the enviornment⁴. In individuals with periodontitis, chronic inflammation leads to increased basil cell proliferation, which in turn leads to higher viral loads in the oral cavity and saliva. There is some speculation that this process could create a reservoir within the oral cavity, leading to sustained HPV infection and the development of oral cancers⁴.

However, there is still no clear association between HPV infection and the development of oral cavity squamous cell carcinoma⁴. As Hill says, “At the end of the day, the ubiquitousness of this virus is unlike anything that we’ve had to deal with in the dental community ever before.”

WHY IS IT SO HARD TO DETECT ORAL CANCERS EARLY?

Unfortunately, oral and oropharyngeal cancers often remain undetected until later stages, when treatment is difficult and often unsuccessful. For individuals with cancer that is diagnosed after metastasis, the five-year relative survival rate is about 38 percent.⁷ This rate hasn’t improved substantially for many years.

Traditionally, dentists have used oral examinations, including visual inspection and palpation, to screen for oral cancers, but it is possible for smaller, more subtle lesions to remain undetected, especially in the oropharyngeal region.

“It’s a difficult area to examine. Dentists are formally trained to examine both the inside and outside of the mouth, and part of the examination of the inside of the mouth would be the base of the tongue and the tonsils,” Schmidt says. “However, it’s hard to see those areas — sometimes directly examining the base of the tongue and the tonsils can be difficult.”

Unfortunately, many dentists do not encounter patients until the cancer has metastasized.

“Many of the oropharyngeal cancers that are related to HPV present with metastasis to the neck,” Schmidt says. “These patients will often present with a lymph node in the neck that the dentist can palpate. They might not show anything in the mouth.”

“Dentists are very good at picking up oral cancers early, but for certain populations — and it depends on access to care – some of these cancers are picked up later,” says Schmidt.

Typically, elderly, low-income, or uninsured patients present with later staged cancers because of economic factors and other barriers to regular dental screening and care.^8,9

HOW CAN DENTISTS BETTER SCREEN FOR ORAL CANCERS?

Effective oral and oropharyngeal cancer screening starts with effective dental education. University programs in the U.S. instruct dental students on appropriate screening methods for oral cancers, but educational efforts should not stop once a dentist graduates. Because oral cancer detection curriculum can vary in dental schools, some research has suggested that proficiency in performing an oral cancer examination should be a requirement for graduation and licensure.¹⁰ Also, continuing education courses that incorporate information about oral cancer epidemiology, pathology, and differential diagnosis offer opportunities to help keep dentists up to date on the latest research and trends.¹⁰

Currently, the National Institute for Dental and Craniofacial Research (NIDCR) recommends dentists perform a thorough head and neck inspection as part of each patient’s routine visit. This examination should include gathering information about each patient’s tobacco and alcohol use, as well as a discussion of other risk factors identified from the patient’s health and dental history. If any suspicious lesions are identified, it is critically important for dentists to follow up with the patient to ensure a definitive diagnosis was made.⁷

Mehdi Karimipour, D.M.D., recommends regular vigilance for higher-risk patients. In an email, he said, “(Dentists should be seen) at least twice a year not only for regular dental checkups, but also for oral cancer screenings. Abnormal tissue growth in and around the mouth can be detected, and X-rays can show signs of cancer.”

In addition to visual inspection, dentists can also use several adjuvant screening methods in efforts to improve cancer detection. Toluidine blue staining has already been used for many years as an oral cancer screening aid,¹¹ allowing dentists to easily identify suspicious oral tissues that are stained dark royal blue. Also, oral brush cytology, in which oral cavity cells are collected after scraping the mucosa with a special brush and analyzed in a laboratory setting, is a non-invasive and inexpensive method of further examination of suspected lesions.¹²

Beyond these methods, many practices have begun screening efforts using new technologies that can be easily incorporated into clinical practice. In her facility, YiChen Wei, D.D.S., makes use of one such technological option, VELscope, to provide better care to her patients.

“VELscope uses a wireless, handheld scope that uses natural tissue fluorescence to enhance the way (we) can visualize oral mucosal abnormalities that might not be apparent or even visible to the naked eye,” Wei says. “We have implement this into our dental practice and it has become routine during exams.”

As Hill says, “(Screening for oral cancer) is a very small part of your daily practice. It’s not going to be hugely time consuming, and you don’t have to go back to school to learn how to do it. It just requires engagement, and saying ‘I believe this is important in my practice. I am the custodian of these patients’ mouths.’ I think if every dentist approaches their patients with that mentality, they will take the time to do what’s right, and we’ll start finding this stuff earlier.”

References

1. Chi, A. C., Day, T. A. and Neville, B. W. “Oral cavity and oropharyngeal squamous cell carcinoma—an update.” CA: A Cancer Journal for Clinicians 65(2005): 401—421. doi:10.3322/caac.21293. doi: 10.3322/caac.21293.

2. Rivera, César. “Essentials of Oral Cancer.” International Journal of Clinical and Experimental Pathology 8.9 (2015): 11884—11894.

3. “What are the key statistics about oral cavity and oropharyngeal cancers?” American Cancer Society, last modified January 6, 2017, accessed February 06, 2017, https://www.cancer.org/cancer/oral-cavity-and-oropharyngeal-cancer/about/key-statistics.html.

4. Hübbers, Christian U, and Baki Akgül. “HPV and Cancer of the Oral Cavity.” Virulence 6.3 (2015): 244—248. doi: 10.1080/21505594.2014.999570.

5. “Oral cancer incidence (new cases) by age, race, and gender,” National Institute of Dental and Craniofacial Research, last modified May 24, 2014, accessed February 06, 2017, https://www.nidcr.nih.gov/DataStatistics/FindDataByTopic/OralCancer/OralCancerIncidence.htm.

6. FAIR Health, “Claims related to oral cancer diagnoses rise 61 percent since 2011,” news release, October 26, 2015, http://www.fairhealth.org/servlet/servlet.FileDownload?file=01532000001vhJR.

7. “Oral health topics: oral and oropharyngeal cancer,” American Dental Association, last modified January 17, 2017, accessed February 06, 2017, http://www.ada.org/en/member-center/oral-health-topics/oral-cancer.

8. Mangalath, Ummar et al. “Recent Trends in Prevention of Oral Cancer.” Journal of International Society of Preventive & Community Dentistry 4.Suppl 3 (2014): S131—S138. doi: 10.4103/2231-0762.149018

9. Jafari, A et al. “Delay in the Diagnosis and Treatment of Oral Cancer.” Journal of Dentistry 14.3 (2013): 146—150.

10. Psoter, Walter J. et al. “Increasing Opportunistic Oral Cancer Screening Examinations: Findings from Focus Groups with General Dentists in Puerto Rico.” Journal of Cancer Education 30.2 (2015): 277—283. doi: 10.1007/s13187-014-0679-x

11. Tohoku J. “Non-invasive techniques for detection and diagnosis of oral potentially malignant disorders.” The Tohoku Journal of Experimental Medicine. 238 (2016):165-177. doi: 10.1620/tjem.238.165.

12. Babshet, M et al. “Efficacy of Oral Brush Cytology in the Evaluation of the Oral Premalignant and Malignant Lesions.” Journal of Cytology / Indian Academy of Cytologists 28.4 (2011): 165—172. doi: 10.4103/0970-9371.86342.