Tumors of the base of the tongue are classified under head and neck cancers; specifically, they develop from epithelial cells located at the posterior one-third of the mucosal layer of the tongue. These tumors are usually of squamous cell type (SCC) and constitute most tumors of this site; other histological types include lymphomas, salivary gland tumors, and sarcomas, but they are much less frequent.

The incidences of base tongue cancers have been on the rise mainly because of the spike in HPV infection as a significant risk factor, especially among young persons. Initially, such cancers were seen in older adults who were heavy smokers and drinkers, but now HPV-related cancers are different entities with better prognosis and different risk factors.

Genetic Mutations and Oncogene Activation:

Abnormalities in the TP53 tumor suppressor gene, PIK3CA, and NOTCH1 result in impaired normal cell cycle regulation. Oncogenes such as those in the EGFR pathway can become activated and stimulate the process of cell proliferation.

Other genes linked to DNA repair mechanisms include BRCA1 and BRCA2, which have also been implicated in the occurrence of the disease.

Risk Factors:

Tobacco and Alcohol Use: These are the common risk factors that are hazardous to human health. They are currently causing diseases among smokers and alcohol drinkers. Tobacco is a direct DNA mutagen, while alcohol is a solvent that increases the uptake of tobacco carcinogens into the mucosa.

Human Papillomavirus (HPV): Some of the established risk factors include HPV, especially type 16. HPV-positive tumors do not act like other tumors due to the action of viral oncoproteins E6 and E7 that target p53 and Rb tumor suppressor proteins, respectively, thus promoting cell proliferation.

Other problems that can lead to mouth infection include poor oral cleanliness and irregular changes that result from the position of objects such as dentures, besides persistent inflammation.

Tumor Microenvironment:

Tumor development progresses under the influence of the local microenvironments encompassing inflammatory cells, cytokines, and growth factors. This is because chronic inflammation and evasions of the immune system enable the growth and metastasis of tumor cells.

Local Invasion and Metastasis:

The base of the tongue cancers tends to invade locally into the floor of the mouth, the tongue muscles, and surrounding lymphatics.

Cervical lymph node metastasis is frequent because the base has rich lymphatic circulation ascends along the lateral tongue’s border. Thus far, distant metastasis has been identified only in two organs: the lung and bone.

Immune Evasion:

It has been found that tumor cells express PD-L1 and other immune checkpoint proteins that allow them to hide from the immune system. This allows the tumor to grow unchecked by the body’s immune defenses.

Human Papillomavirus (HPV) Infection: HPV, especially HPV type 16, has been known to be linked with oropharyngeal squamous cell carcinoma, including base tongue tumors. In terms of patient survival, there is an indication that HPV-positive tumors are more favorable than HPV-negative tumors.

Tobacco and Alcohol Use: Heavy smokers and alcohol consumers are considered high-risk factors for malignancies that affect the oral cavity and the oropharynx region. Altogether, these aspects significantly increase the probability of an occurrence.

Chronic Irritation: Prolonged irritation due to ill-shaped dentures or GERD might be some of the causes for malignant change in some patients.

Genetic Factors: Certain inherited gene trends and mutations may be implicated in malignancy tumors. Benign conditions like Fanconi anemia and Li-Fraumeni syndrome has been stated to predispose individuals to CVD.

Environmental and Occupational Exposure: Some of the causes of oral cancer may include contact with chemicals together with toxic pollutants in the environment.

Immune System Factors: Any condition that weakens the body’s immune system makes it easier for one to develop cancer or for a cancer to progress, and thus immunosuppression or immunodeficiency puts one at higher risk of developing cancers of the base of the tongue.

Chronic Inflammation: Inflammatory diseases of the oral cavity increase the probability of neoplastic transformations in the process of the disease’s progression.

The survival rate of malignant tumours of the base of the tongue depends on such factors as tumour stage at diagnosis, tumour size, nodal involvement and the general health status of the patient. In general, these tumors are first diagnosed at an advanced stage because of their location, and hence, prognosis is poor.

Age Group:

Cancer of the base of the tongue affects mainly adults and the most affected age range is between 50 and 70 years. But there was an apparent increase in recent years, especially among the young adults, especially associated with the HPV virus. The disease is more prevalent in men than in women.

Visual Inspection

Palpation

Assessment of Mobility

Neck Examination

Oropharyngeal Examination

Symptom Assessment

Tobacco and Alcohol Use

Human Papillomavirus (HPV) Infection

Poor Oral Hygiene

Dysphagia and Aspiration

Nutritional Deficiencies

Metastasis

The base of the tongue malignant neoplasms has late-stage presentations since early signs and symptoms are not easily detectable because of its location. Their characteristics are long standing pain, sore throat, dysphagia, otalgia and neck nodal enlargement due to metastasis. One of the biggest challenges of these tumors is that the disease is usually diagnosed at an advanced stage because symptoms in the early stages are hard to distinguish from typical diseases. Imaging procedures, biopsy, and endoscopic examination are some of the common diagnostic procedures applied in the diagnosis of colon cancer. Its diagnosis at an early stage is difficult, and the survival depends on the stage at time of presentation and their response to therapy.

Surgical Resection: Surgery is usually the initial therapy, and it eradicates as much of the tumor and the adjoining tissue. The magnitude of surgery depends on the size and stage of the tumor.

Radiotherapy: In most cases, radiation therapy is indicated either in the primary treatment plan for those tumors that cannot be removed surgically or as an adjuvant in the postsurgical management when there are residual cancer cells. It can also be used in a pallitative form of treating the condition, where a patient is administered with non-curative treatment, but their symptoms are eased.

Chemotherapy: Chemotherapy can be given together with radiation (chemo radiation) especially with advanced stages or can be used before the surgery in the form of neoadjuvant therapy to reduce the size of the tumor. It can also be used for the management of symptoms of the final stage of cancer, or any other terminal illness known as palliative care for metastatic disease.

Targeted Therapy and Immunotherapy: These are relatively newer treatment modalities and may be considered depending on the type of tumor and the patient. Targeted therapy is more specific because it focuses on proteins mainly present in cancer cells, while immunotherapy assists the immune system in identifying destroying cells.

Supportive Care: Management of symptoms and support for nutrition, speech, and overall well-being are crucial aspects of treatment, especially in advanced cases.

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Clinical Setting:

Multidisciplinary Care: Ensure that parents get access to a team of specialists. They include oncologists, radiologists, surgeons, and speech and swallowing therapists.

Advanced Imaging: PET/CT is recommended for staging, mapping, and planning the management of cancer.

Treatment Environment:

Nutritional Support: Consult with dietitians in case there are issues related to eating and swallowing to ensure that the patients are adequately nourished.

Psychological Support: Provision of counselling and support groups should also be provided to enable the patient to deal with the psychological problems of the illness and the treatment.

Home Environment:

Accessibility: Make sure that the environment within the patient’s home is safe and appropriate to cater to any changes in their mobility status.

Follow-up Care:

Regular Monitoring: It is recommended to have follow-up appointments after a specific interval to look for any signs of tissue recurrence and to deal with the treatment outcomes.

Rehabilitation Services: Consider incorporating speech and language therapy to solve long-term speech or swallowing anomalies.

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Pembrolizumab and nivolumab

The application of immunotherapy has received tremendous attention, especially with immune checkpoint inhibitors like pembrolizumab and nivolumab, with many ongoing trials, but now, it is majorly used in palliative settings for patients with retreated oropharyngeal SCC. given the current knowledge regarding the treatments, the management of oropharyngeal SCC could be promising using immunotherapy.

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Intervention with procedure

Treatment approaches towards the base of tongue malignant neoplasms are mainly surgical intervention, which has the aim of resecting the malignant tumor with minimum impairment to anatomical and functional structures.

Some common approaches used are:

Partial Glossectomy: This procedure involves removing part of the tongue where the tumor is located. It is often used for smaller tumors or those that are confined to one area.

Total Glossectomy: When it becomes necessary to remove all the part of tongue or when the tumor is large. In this case, a total glossectomy is performed. This is a more severe type of injury and may need reconstructive surgery to be able to regain functionality as well as appearance.

Neck Dissection: Due to the anatomic location of the base of tongue tumors, they may metastasize to the cervical lymph nodes, and hence, a Neck dissection may be done to remove the involved lymph nodes to minimize the transfer of cancer.

Reconstructive Surgery: Reconstructive surgery could be required to perform a reconstruction with flaps after tumor removal and to rebuild the specific part of the mouth such as the tongue by harvesting tissue from a specific part of the body.

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Diagnosis and Staging:

Clinical Evaluation: It consists of a clear history and a physical examination.

Imaging Studies: The extent of the diseases is determined using CT scans, MRI, and PET scans for any metastatic diseases.

Biopsy: A biopsy is usually done for confirmation of the disease and the identification of the histological type of cancer.

Treatment Planning:

Multidisciplinary Team Review: It targets all the organizational oncologists, surgeons, radiologists, and other related specialists to create an effective treatment plan.

Staging: Establishes the size of the tumor and assists in deciding on the best action to take.

Treatment:

Surgery: May call for partial or total glossectomy depending with the size and stage of tumor.

Radiotherapy: Sometimes prescribed after surgery or as an initial course of chemotherapy for non-operable tumors. It affected cancerous cells with high-energy rays.

Chemotherapy: This may be given in conjunction with irradiation (chemoradiation) or in the absence of other options for treating sufficiently advanced tumors.

Targeted Therapy: If a definite change of the gene or molecular marker in the cancer is detected.

Post-Treatment Follow-Up:

Regular Monitoring: They undergo routine physical examinations, imaging, and serological tests to determine recurrence or metastasis.

Rehabilitation: This may involve speech therapy, dietary adjustments, and other supportive care to address functional and quality-of-life issues.

Palliative Care:

Symptom Management: The primary aim is to help patients with severe or progressive disease or those whose disease is incurable to feel better.