Introduction

Oral cancer, often termed the "silent killer," involves malignancies that arise in the mouth and throat.¹ These cancers can develop in any part of the oral cavity, frequently remaining dormant before abruptly growing and causing severe issues. They usually present subtle symptoms and can appear in various forms, making early detection essential to prevent rapid progression and reduce discomfort.² 

In this article, we will offer a thorough overview of oral cancer, exploring its molecular mechanisms, clinical manifestations, diagnostic techniques, and treatment options. We will highlight the critical importance of early detection to halt the disease's advancement and mitigate further harm, We will also discuss how prompt diagnosis can significantly improve the quality of life for those affected.

Growth of oral cancer

Oral cancer, a subgroup of oropharyngeal cancers and part of the head and neck region cancer, refers to malignant (cancerous) growths in the mouth, lips, tongue, cheeks, gums, floor of the mouth, and palate. They affect the throat and tonsils, making it difficult to carry out simple activities such as eating or speaking.³ Their growth could begin because of various bacteria, viruses, fungi, and other lifestyle factors, which show a range of clinical presentations when visiting the dentist.⁴

 Some of the main reasons for their growth could be viral infections, such as human papillomavirus (HPV), herpes simplex virus (HSV), and Epstein-Barr virus (EBV), most commonly found in children and adolescents.⁵ Bacterial infections include Porphyromonas gingivalis, Actinomyces species, and Treponema denticola. Or fungi, such as Candida species, leading to chronic oral candidiasis (oral thrush), commonly seen in immunocompromised individuals and as a consequence of other lifestyle choices like smoking, alcohol consumption, and chewing betel nut.⁴

At a molecular level

Here's a detailed timeline of the seven stages of oral cancer growth, focusing on its genetic invasion to immune system invasion:

Stage 1: Genetic mutation (Initiation)

Oral cancers begin with genetic mutations in the DNA of oral cells. Various factors mentioned above can initiate this. Oncogenes (cancer-promoting genes) are activated, or tumour-suppressor genes (controlling cell division) are inactivated, both causing mutations to normal cells, which result in the proliferation of cells forming abnormal cells. The abnormal growth is not so easily seen at the early stages of cancer development.⁶

Stage 2: Hyperplasia (Early cellular changes)

Mutated cells begin dividing uncontrollably, resulting in an increase in abnormal cells, a condition referred to as hyperplasia. Dysplasia, an early sign of hyperplasia, involves localised, non-invasive abnormal cell growth. At this stage, cellular changes are undetectable without a biopsy, although oral lesions may appear, which are typically benign.⁷

Stage 3: Dysplasia (Pre-cancerous changes)

A greater level of disorganisation in cell growth is visible with a mass protruding from the surface. The severity of dysplasia can vary based on the abnormality of the cell. At this stage, the cancer is not invasive as the basement membrane (separating the surface of the epithelium from deeper tissues) is still intact. However, pre-cancerous changes may be visible as oral lesions become more distinct in the form of white (leukoplakia) or red (erythroplakia) patches in the mouth.⁸

Stage 4: Carcinoma in situ (CIS)

CIS is the last stage before true invasive cancer. At this stage, cancerous cells adhere to the surface epithelium. They have not breached the basement membrane. Diagnosing oral cancer at this stage is beneficial to avoid more invasive treatments. Oral lesions become more visible, and other symptoms, such as soreness and irritation, are also present.⁹

Stage 5: Invasive carcinoma (Initial invasion)

At this stage, cancer cells start forming tumours and invading beyond the surface epithelium into deeper connective tissues and other tissues such as the lamina propria, muscles, and nerves in the oral cavity. Symptoms include pain, difficulty swallowing, or loose teeth may be felt.⁷

Stage 6: Regional spread (Lymphatic invasion)

The cancer spreads to lymph nodes in the head and neck region, specifically the cervical lymph nodes in the neck. Lymphatic vessels are invaded, allowing cancer cells to metastasise to lymph nodes. Enlarged lymph nodes may be palpable or visible. Additional symptoms include swelling in the neck and changes in voice or speech. The prognosis worsens as the cancer becomes harder to contain.¹⁰

Stage 7: Distant metastasis (Immune system invasion)

The cancer has now spread to various organs such as the lungs, liver, or bones, and tumour cells have successfully evaded immune detection, and secondary tumours have also been placed in distinct parts of the body. Symptoms have become more systemic, too, with signs of fatigue, weight loss, and pain. Treatment options at this stage include palliative treatment or systemic therapies, chemotherapy, and targeted therapy.¹¹

Diagnosis

It is crucial that oral cancers are identified and diagnosed as early as possible to improve treatment outcomes. Recognising the key symptoms and clinical signs is vital for healthcare professionals to initiate timely interventions. Common symptoms of oral cancer include:¹²

• Persistent sores in the mouth or on the lips
• A lump or thickening of the skin or lining of the mouth
• Red or white patches inside the mouth
• Difficulty swallowing, chewing, or speaking
• Numbness or pain in the mouth or face
• Unexplained weight loss
• Persistent bad breath

Early detection of these symptoms can significantly improve the chances of successful treatment and recovery. According to the World Health Organization (WHO), oral cancer affects over 377,700 people globally each year. Unfortunately, only about 30% of these cases are diagnosed at an early stage, where treatments like localised surgery or radiation may be effective. In contrast, the remaining 70% are diagnosed at a more advanced stage, often requiring more invasive procedures such as extensive surgery, chemotherapy, or even reconstructive treatments.¹³ 

This highlights the critical importance of regular dental check-ups and promptly addressing any changes, as early diagnosis can reduce the need for aggressive interventions and improve survival rates. Moreover, it suggests the importance of the multidisciplinary team (MDT) to work together in successfully diagnosing the problem, and a collaborative effort among general practitioners, specialists, and dental professionals is required to boost early detection rates.¹⁴

Technology in diagnosis

Using technology, such as fluorescence-based tools and VELscope, has greatly advanced the accuracy of cancer screenings in dentistry. Fluorescence-based tools work by emitting specific wavelengths of light that interact with the tissues in the mouth, causing abnormal tissues to fluoresce differently from healthy tissues. This makes it easier to identify areas that might not be visible during a regular examination.¹⁵

VELscope employs blue light to detect subtle changes in the oral mucosa, which can indicate the presence of precancerous or cancerous cells before they become clinically apparent. These advanced screening methods provide a more detailed view of the oral cavity, allowing for earlier detection and intervention, and improving the chances of successful treatment. By incorporating these technologies into routine dental check-ups, practitioners can offer a more comprehensive approach to oral cancer detection and prevention.¹⁵

Treatment

Treatment options for oral cancer vary depending on the stage of the disease, but common approaches include:¹⁶

• Surgery: removal of the tumour and surrounding tissues; advanced cases may require reconstruction of the mouth or jaw
• Radiation therapy: Targeted radiation is used to kill cancer cells, often combined with surgery or chemotherapy for more advanced stages
• Chemotherapy: use of drugs to kill or shrink cancer cells, often used for advanced or metastatic oral cancer
• Targeted therapy: drugs that specifically target cancer cell growth, often used when cancer has spread or returned
• Immunotherapy: boosts the body’s immune system to help fight cancer, typically used in cases where other treatments are less effective
• Post-treatment care: speech therapy, swallowing therapy, or dental prosthetics to help patients regain normal function after treatment

Prevention

To reduce the risk of oral cancer, it's important to avoid tobacco products and limit alcohol consumption, as these are major risk factors. Maintaining a healthy diet rich in fruits and vegetables, practicing good oral hygiene, and using sunscreen on your lips can also help.¹⁷

Regular dental check-ups are essential for early detection, while being aware of personal risk factors and monitoring any unusual changes in your mouth is crucial. Additionally, getting vaccinated against HPV can offer protection from certain types of oral cancers. By combining these strategies, you can significantly lower your risk and promote better oral health.¹⁷

Future advancements

Future advancements in oral cancer detection and treatment promise to further enhance early diagnosis, and personalised care like:¹⁸

• Advanced imaging techniques, including 3D and hyperspectral imaging, are expected to offer even more detailed views of oral tissues, improving the ability to spot subtle changes and early-stage cancers
• Using liquid biopsies for more non-invasive detection of cancer biomarkers in saliva or blood, facilitating earlier and more accurate diagnosis
• Artificial intelligence (AI) and machine learning to improve the analysis of screening results with more accuracy
• Targeted therapies and immunotherapies for more effective and tailored treatment options

FAQs

How does Fluorescence and VELscope help diagnose?

It highlights abnormal tissues and detects early signs of cancer.

How does molecular diagnosis help?

It offers precise detection and tailored treatments.

Why is teamwork crucial in oral cancer detection? 

It brings about collaboration among MDT to improve diagnosis and treatment success.

How does public awareness help prevent oral cancer?

Patients can make more informed choices and go to regular dental check-ups and diagnoses.¹⁹

Read on:

If you enjoyed reading this article from Klarity, you will enjoy reading:

• Complications, Causes, And Preventive Measures For Oral Cancer
• Oral Cancer And Mental Health
• Overview Of Oral Cancer
• Oral Cancer Treatment Options

Summary

Oral cancer research is evolving, needing tailored treatments based on the stages and presentation. Understanding the disease helps prevent it. Advances like fluorescence-based tools and VELscope improve early detection by highlighting abnormal tissues. A collaborative approach with healthcare professionals boosts early diagnosis. Future advances in molecular diagnostics and personalised therapies promise even better detection and treatment. Despite progress, the fight continues. It is important to inform patients about regular screenings and innovative treatment options.