ORAL CANCER

Cancer that develops in the oral cavity or mouth is called Oral cancer or mouth cancer. It is one of the highly prevalent diseases in the world with higher mortality rates. It is the 6^th most common cancer in the world and 3^rd most common in Asia.

The statistics of who is fascinating. There are almost 657000 new cases of head and neck cancers reported each year. Sadly 330000 cases of mortality from oral cancer are reported every year.

The main reason for such devastating statistical numbers correlates to lack of proper information on early detection and prompt treatment of oral cancer. The prognosis of oral cancer is high if it is identified at an early stage and treated.

RISK FACTORS

The primary risk factors associated with oral cancer include tobacco and alcohol. Any form of smoking [chewing/smoking] is harmful. The byproducts from smoke are carcinogenic and have a profound impact on the initiation of oral cancer.

There are 7000 chemicals released in smoking. Out of them, 250 play vital role in oral cancer.

These chemicals irritate the mucosa within the oral cavity and penetrate the cells causing severe damage to the nuclear material. The high temperatures produced during smoking facilitate smooth infusion of these chemicals into the human cells. It results in chromosomal aberrations leading to oral cancer.

Alcohol creates severe dryness by absorbing water from cells in the oral cavity. As a result, cells become dry and remain accessible to perfusion of harmful chemicals. Alcohol associated with smoking is a significant risk factor.

The other risk factors include

• Familial history of oral or any cancer: Some genes code for specific cancer types. They usually run in families. Hence patients with familial history of oral cancer are more prone to develop oral cancer than their counterparts.
• Poor nutritional status: many of the South Asian and African countries have people below the poverty line. They have an inadequate nutritious supply.
• Frequent exposure to harmful chemicals like heavy metals and other carcinogens: People working in chemical factories are more prone to develop cancer.
• Gender: Men are twice commonly affected than women.

TYPES OF ORAL CANCER

Based on the region of the presentation, we can see various kinds of oral cancer involving:

Lips: Cancer on lips start as white patches, which slowly increase in size resulting in ulcerations. These ulcerations may later affect deeper tissues causing hardening of lips. Cancer on lips is the least common oral cancer. According to a study conducted at Thames cancer registry, the mean incidence of cancer on the lip is only 2.3%.

Tongue & floor of the mouth: Tongue cancer is the most common oral cancers in the oral cavity. The lesions on tongue start as white or red patches associated with de-papillation of the tongue. As time passes they turn into ulcerations and exophytic growths.

Patients usually experience loss of taste sensation — involvement of tongue results in altered speech and difficulty in tongue movements.

Gums: Cancer on gums is a rare entity and is usually associates with bone involvement. The presentation represents a small exophytic nodular growth on the gums area — radiographs aid in identifying bony involvement.

Cancer involving gums require an extensive excision of underlying bone along with tumour mass.

Cheek: Cancer on the cheek is a common finding in people who chew smokeless tobacco. Tobacco products like KHAINI, PAN, GUTKHA are carcinogenic. People who use these products tend to keep them in the cheek region for more extended periods.

The cheek mucosa gets irritated, resulting in altered mucosa. It appears as a diffuse white patch in the initial days. Slowly red regions develop in these areas resulting in malignant transformation. Usually, these mucosae appear with multiple folds with white spots.

The cheek in smokers has a peculiar presentation of severe pigmentation.

Palate and pharynx: Palatal involvement in oral cancer is seen more in smokers. Palatal mucosa is the first tissue that comes in direct contact with the lit end of the cigar. Hence they are more exposed to the carcinogens from the smoke.

In the initial stages of smoking multiple hyper-pigmented [dark coloured] and hypo-pigmented [light coloured] areas develop in the palate.

The next stage represents multiple white excrescences due to hyperkeratosis. In a few cases, localised areas of white lesions appear on the palate. On long-standing novice red areas develop within these white areas leading to oral cancer.

Smokers usually have a high rate of palatal cancer.

ORAL CANCER SYMPTOMS

The overall mortality rate of oral cancer is near to 2%, which is pathetic. Recognising the signs of oral cancer at an early stage is life-saving.

Identifying oral cancer at an early stage is a difficult task. Here are a few symptoms which can indicate a developing oral cancer lesion.

Cachexia: Patients experience severe weight loss.

Red or white lesions in the mouth:

The appearance of a red or a white lesion [or mixed red and white injury] is an absolute indication of a change in underlying tissue. These developing red and white lesions may represent erythroplakia and leukoplakia, respectively.

Leukoplakia is a white lesion that can develop in any part of the oral cavity. Usually, these lesions transform into cancer, bearing a chance ranging from 1 to 17%.

Erythroplakia is a red lesion that has more chance of developing cancer when compared to leukoplakia. In addition to it, the malignant transformation rate ranges between 1.4% to an enormous 36%, which is colossal.

Painless ulcer or growth:

Patients with cancer develop ulcers associated with disproportionately grown tissue masses within the mouth. The presentation of a massive ulcer over a large tissue mass is a definite prediction of cancer.

Sour mouth and numbness:

Patients with cancer have altered taste sensation. It is one of the many findings that we can observe in these patients. But the presence of sour mouth and numbness can never be a confirmatory diagnosis for cancer.

Severe malodour:

Cancer patients have stern bad breath. It usually happens due to underlying tissue necrosis in the ulcerated areas.

Profuse bleeding:

The ulcerations on cancer lesions bleed profusely, even on slight touch.

Restricted tongue movements or difficulty in speech:

Patients with oral cancer on the tongue have difficulty in moving their tongue. Constrained tongue movements with talking and swallowing problems are frequent in these patients.

ORAL CANCER SCREENING

The 5-year survival rate of oral cancer patient is only 65%. But early diagnosis can increase the survival rate from 65 to 84%.

But, how can we diagnose oral cancer at an early stage? It can be done by oral cancer screening. People should participate in sizeable community screening programs for early detection of oral cancer.

Governments are spending a gigantic portion of their budget in oral cancer screening programs. Here are a few procedures that you should do in case of cancer apprehension.

• Make an appointment with your dentist.
• Have a thorough dental checkup.
• Ask for an expert opinion. Your dentist may arrange an appointment with an oral medicine expert or may refer to an oncology institute.
• Participate in all the examinations without any hesitation. The investigations may include a biopsy and some radiographs [x-rays films].
• Let the reports decide the diagnosis. Don’t be in a panic.
• HAVE A SECOND OPINION IN CASE OF DOUBT.

Many advanced cancer screening tools are available for patients.  It includes the following protocol

VISUAL EXAMINATION

The screening protocol consists of a thorough examination of the oral cavity. Any altered tissue structures or red and white lesions are to subjected to further investigations.

VELSCOPE, VIZILITE PLUS, ORASCOPTIC

VEL scope is a screening instrument for evaluating abnormalities in tissue fluorescence. Healthy tissues produce typical fluorescence, which seems to be lacking in cancer tissues.

Vizilite plus works on the principle of chemiluminescence to identify abnormal tissues in the oral mucosa.

While orascoptic DK is a led light source to identify unusual and suspicious tissues in the oral cavity.

All the above appliances are used to determine and identify abnormal tissues. There can be false positives and false negatives.

Hence further investigations are necessary for confirmation.

SMEAR/ ORAL CDX / BRUSH BIOPSY

Brush biopsy helps in collecting deeper cells from suspecting regions. It aids in identifying cells from deeper tissues causing no harm to them.

RADIOGRAPHS

Radiographs like CT, MRI and ultrasound aid in identifying the exact dimensions of the lesion. Knowing the aspects and shape of the lesion is vital in treatment planning.

HOW SHOULD I PROCEED AFTER SCREENING

Oral cancer screening helps in identifying the probability and severity of oral cancer. After having a confirmatory diagnosis, your dentist may refer you to an oncology institute for further treatment.

ORAL CANCER TREATMENT

The management of cancer deals with three different treatment modalities. Some tumours may require RADIOTHERAPY, while some others require only CHEMOTHERAPY. Some cases can be cured only by simple excision or SURGICAL REMOVAL.

After having a thorough examination and investigations, the oncologist [cancer specialist] decides the best treatment that suits the tumour.

ORAL CANCER STAGES

The staging of oral cancer comes under three categories. As a whole, it is called TNM staging.

T = tumour          N = Lymphnode involvement     M = Metastasis.

Each tumour is classified by its size (T), Number and type of lymph nodes involved (N) and the presence and absence of metastasis (M).

The ability of a tumour to enter into other regions of the body is called metastasis. In simple words, if a tumour spreads from the oral cavity to the lungs, it is called metastasis.

The oral cancer foundation has given tumour staging for the lips and oral cavity.

BASED ON TUMOR SIZE [T]

• TX Primary tumour cannot be assessed
• T0 No evidence of primary tumour Tis Carcinoma in situ
• T1 Tumor 2 cm or less in greatest dimension
• T2 Tumor more than 2 cm but not more than 4 cm in greatest dimension
• T3 Tumor more than 4 cm in greatest dimension
• T4a Lip Tumor invades through cortical bone, inferior alveolar nerve, floor of mouth, or skin of face (ie, chin or nose)* Oral Cavity Tumor invades through cortical bone, into deep extrinsic muscle of tongue (genioglossus, hyoglossus, palatoglossus, and styloglossus), maxillary sinus, or skin of face
• T4b Tumor involves masticator space, pterygoid plates, or skull base and/or encases internal carotid artery

BASED ON LYMPH NODE INVOLVEMENT [N]

• Nx Regional lymph nodes cannot be assessed
• N0 No regional lymph node metastasis
• N1 Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension
• N2 Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension; or in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension; or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension
• N2a Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension
• N2b Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension
• N2c Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension
• N3 Metastasis in a lymph more than 6 cm in greatest dimension

BASED ON PRESENCE OR ABSENCE OF METASTASIS

• Mx Distant metastasis cannot be assessed
• M0 No distant metastasis
• M1 Distant metastasis

STAGING OF ORAL CANCER

STAGE 0

• Tis N0 M0

STAGE I

• T1 N0 M0

STAGE II

• T2 N0 M0

STAGE III

• T3 N0 M0
• T1 N1 M0
• T2 N1 M0
• T3 N1 M0

STAGE IVA

• T4a N0 M0
• T4a N1 M0
• T1 N2 M0
• T2 N2 M0
• T3 N2 M0
• T4a N2 M0

STAGE IVB

• T4b Any N M0
• Any T N3 M0

STAGE IVC

• Any T Any N M1

QUESTION & ANSWERS

ORAL CANCER STAGE 4 LIFE EXPECTANCY

The 5 YEAR survival rate of oral cancer ranges between 45% to 65% depending on the stage of the disease. According to the statistics of the NATIONAL CANCER INSTITUTE IN 2019, the five-year life expectancy is as follows: https://seer.cancer.gov/statfacts/html/oralcav.html

• Cancer with no metastasis and lymph node involvement [stage I & II] is 84.4%
• Cancer with regional lymph node involvement [stage III} is 66%
• Cancer with distant metastasis [stage IV] is 39.1%
• Unstaged  cancers has a life expectancy of 50.9%

ORAL CANCER RECURRENCE RATE

The recurrence rate of oral cancer depends on many factors like age, gender, type of cancer, region of cancer and staging of cancer. The overall recurrence rate of cancer was advocated as 32.7% by bo wang et al. in his study. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3845544/

CAN ORAL CANCER SPREAD TO ANOTHER PERSON?

No oral cancer is not contagious. It will not spread to another person. There are some risk factors which aid in developing cancer. Most of the occurrences are due to habits and genetic constitution of the person.

DOES ROOT CANAL CAUSE ORAL CANCER?

Root canals do not cause cancer. It is a misconception. The American Academy of endodontics advocates root canal as a safe procedure. Know more about root canal and cancer CLICK HERE.

WHAT IS IMMUNOTHERAPY FOR ORAL CANCER?

It is a mode of treatment where the body’s immunity is strengthened using a group of drugs called IMMUNOMODULATORS. Further, the enhanced immune system is directed against cancer cells.

WHERE DOES ORAL CANCER SPREAD TO?

Usually, cancer spread to regional lymph nodes. Based on the involvement of lymph nodes, the severity of the disease is assessed. TNM staging aids in assessing the severity of the disease.

The process of spreading oral cancer to distinct area in the body is known as METASTASIS. Usually, metastasis from cancer occurs in lungs, liver and kidneys.

CAN ORAL CANCER BE CURED?

Yes! Oral cancer can be cured. The latest treatment modalities like robotic arm cyberknife surgery and LINEAC machines in radiotherapy and recent developments in cancer chemotherapy have increased the 5-year survival rate of patients.

Early diagnosis, prompt treatment can help in a good prognosis.

CONCLUSION

Early detection of cancer can have a dramatic increase in the survival rates of the patients. Recent advances in diagnostic modalities made it possible to identify cancer at an early stage. Patient education towards oral cancer and its risk factors should be the primary agenda of governments to curb the disease progression.