Precancerous and Cancerous Growths
A routine part of an oral examination should be inspection not only of the teeth and gums but also of the soft tissues in and around the mouth. Dentists look for abnormal changes that are loosely called “lesions.”
Many lesions are innocuous and can be easily diagnosed and named based upon their appearance alone. However, some lesions are not as easy to identify and require additional diagnostic steps, such as a biopsy (removal of a piece of the lesion to examine under a microscope). A small percentage of these lesions may be premalignant or even malignant.
What are these? Premalignant or precancerous (also referred to as “potentially malignant”) oral lesions involve the skin lining of the mouth (known as the epithelium) and may be at risk for becoming (transforming into) an oral cancer, although it is difficult to predict which lesions will transform and how long it will take (see below).
Who is at risk for these? As we grow older our risk of developing cancer increases. The same is true for premalignant lesions. Most lesions are detected in people over the age of 40 and those with similar risk factors for oral cancer, such as tobacco and/or heavy alcohol use, although such lesions can also be found in younger individuals and/or those without classic risk factors.
How are oral lesions detected? Premalignant lesions and early cancers are usually asymptomatic (ie the patient has no pain and they don’t even know they have a lesion), so their detection is contingent upon a careful soft tissue examination by a dentist. This examination must include the inside and outside of the lips, the cheeks (buccal mucosa), the sides and undersurface of the tongue, the floor of mouth, the gums, the roof of the mouth (palate), the back of the mouth/top of the throat (oropharynx). Most oral lesions are traumatic in nature and have no potential for cancer (Figure A). However, some oral lesions have an appearance which may raise suspicion by the dentist.
| Figure A: The whitish line is a common lesion that develops as a reaction to pressure of the soft tissue against the teeth. This readily identifiable lesion is termed linea alba (white line) and has no potential for cancer. |
Which lesions might raise suspicion? Patches that are, red, white or mixed red/white in color, or that may also be ulcerated, especially when found on “high-risk” sites such as the side (lateral surface), underside of the tongue (ventral surface), floor of mouth, or at the back of mouth/top of the throat (oropharynx). A white patch that cannot be wiped off with gauze and for which an explanation is not obvious to the dentist may be defined as a leukoplakia (Figure B & C next page). Similarly, reddish patches with no obvious cause can be defined as erythroplakia (Figure D next page) and mixed red and white areas termed erythroleukoplakia (Figure E next page). Lesions with a red component carry the highest potential for being premalignant or becoming malignant. Some dentists use additional technologies to look for or characterize suspicious lesions (known as diagnostic adjuncts). It is essential to establish an accurate diagnosis for all such lesions that raise suspicion.
