Oral cancer screening is a process where healthcare professionals examine your mouth, throat and neck for signs of oral cancer. They use their fingers to feel (palpate) for lumps and bumps.
They may also shine a special light into your mouth and look for any areas that are glowing or discoloured. This method is called exfoliative cytology.
Oral Cancer Risk Factors
Oral cancer is a disease that affects the tongue, gums, cheek, lips and roof of the mouth (the palate) as well as the back of the throat (the pharynx). Cancer can also develop in the glands that make saliva. It is important to know that oral cancers are very treatable. In fact, most people with stage 1 and 2 oral cancers survive for five years or more after diagnosis and treatment. However, the longer it is between when a person notices a problem and when they are diagnosed with oral cancer, the more difficult it is to cure them.
There are several risk factors for developing oral cancer including tobacco and alcohol use, certain types of human papillomavirus (HPV) infection, and age. Men are more likely to develop oral and oropharyngeal cancer than women. People with fair skin are at a higher risk of developing cancer on the lips.
Studies have shown that smoking or chewing tobacco increases the risk of developing oral and oropharyngeal cancers. It is also known that heavy alcohol consumption increases the risk of these cancers as well. In addition, the genetic factor GSTM1 null genotype is associated with a 20-50% increased risk of head and neck squamous cell carcinoma (HNSCC) including oral cancer. The Kerala Oral Cancer Screening Trial showed that a screening program using visual inspection by trained health workers (three triennial rounds) reduced oral cancer mortality. This reduction was more pronounced in ever-tobacco and/or ever-alcohol users than in never-users of tobacco or alcohol.
Oral Cancer Symptoms
The early detection of oral cancer improves the chance of survival. Most of the time, oral cancers are confined to one area in the mouth and have not spread to nearby tissues or lymph nodes when they are diagnosed at stage 1. If caught at an earlier stage, many oral cancers can be treated successfully.
Cancers may appear as red or white patches inside the mouth that are smooth or rough and bleed easily when scraped. These are called leukoplakia and are a sign of precancerous conditions, including oral squamous cell carcinoma (the most common type of oral cancer) and HPV-related cancers caused by human papilloma virus (the same one that causes genital warts). Most of these changes in the mouth are not cancer but they should be checked by a dentist or doctor because if left untreated, some can become malignant.
Screening involves a visual inspection of the lips, mouth and surrounding tissues. A simple examination can be performed by dental professionals or primary health care workers with minimal training. Several studies show that PHCWs can perform a visual inspection of the oral cavity and connective tissues with similar accuracy to trained dental practitioners. This approach is particularly relevant in low and middle income countries with a high incidence of oral cancer and limited resources to train medical and dental staff for organized screening programs.
Oral Cancer Diagnosis
When a patient visits their healthcare professional for a routine dental checkup, they may be asked to look at their neck and jaw area for any lumps or bumps. Many healthcare professionals use tools, like a toluidine blue dye test or a luminescent light, to help detect any abnormal cells. They also use their fingers to feel (palpate) for any areas that are sore or tender.
These visual screening tests can help detect early-stage oral cancers. However, they do not provide a definitive diagnosis. Ideally, the index test should be validated against an appropriate gold standard – in this case, a histopathological diagnosis by an expert. Unfortunately, very few studies have done this.
The survival benefits of oral cancer treatments depend on how early the cancer is detected. “Aggressive” oral squamous cell carcinomas (OSCCs) progress very quickly and are unlikely to be detected by screening. “Less aggressive” OSCCs develop from long-standing OPMDs and progress more slowly (hence their less steep curve). They are more likely to be detected by screening. These 4 scenarios illustrate the concept of lead time bias/overdiagnosis.
If a healthcare professional finds any unusual areas in the mouth, they will usually take a sample for further testing. The healthcare professional can do this by brushing the area or using a special tool to scrape off a small amount of cells. These samples will then be tested under a microscope for cancerous or precancerous cells.
Oral Cancer Treatment
People with early-stage oral cancer have good survival rates if they are diagnosed and treated quickly. However, many people with oral cancer are diagnosed after the tumor has spread, which can limit their ability to treat it successfully.
Healthcare professionals recommend that everyone examine their mouth, tongue, gums, and throat in the mirror at least once a month for any changes such as lumps or sores. They should also make note of how often these changes occur and tell their healthcare provider if they persist for more than 2 weeks.
Screening programs may detect asymptomatic cases of oral cancer or pre-cancer and provide an opportunity to refer them for more specific diagnostic procedures. However, these programs may also lead to overdiagnosis and overtreatment. The relative efficacy of screening varies by patient risk, and the absolute benefit is greatest in individuals at the highest model-predicted 7-year risk of oral cancer incidence (see figure).
The USPSTF finds that the current evidence is insufficient to assess the balance of benefits and harms of oral cancer screening in asymptomatic adults by primary care providers. This recommendation is based on the fact that only a few studies have evaluated visual inspection of the oral cavity alone; the majority of these have included a combination of screening techniques. Moreover, only 3 of the 7 studies reported on outcomes in which primary care health workers performed oral cancer screening; the other 4 were conducted by dental providers or otolaryngologists.