What is throat cancer?
Throat cancer is a type of head and neck cancer occurring in the pharynx (throat). Throat begins in the area behind the nose and mouth and extends till the esophagus (feeding tube). Pharynx is divided into three sub divisions - nasopharynx (part of pharynx behind the nose), oropharynx (part of pharynx behind the mouth) and hypopharynx (part of pharynx just above the esophagus). Approximately 10% of the head and neck cancers, world over, annually have their origin in oropharynx.
Types and sub-types of throat cancer
There are three subtypes of cancer of pharynx:
- Nasopharyngeal cancer: It includes the cancer of the nasopharynx.
- Oropharyngeal cancer: They include cancers of the tonsils, base of tongue and soft palate. Almost half of oropharyngeal cancers are formed by those arising from the tonsils and its pillars.
- Hypo pharyngeal cancer: They include cancers of the pyriform sinus, post cricoid and posterior pharyngeal wall.
Most of the throat cancers are squamous cell carcinomas.
Symptoms of throat cancer
Patients usually present with multiple symptoms which include:
- Persistent cough
- Changes in voice or hoarseness
- Difficulty swallowing
- Ear pain
- Sore throat
- Weight loss
- Lump in the neck
- Bad odour due to necrosis of the tumour
- Nasal regurgitation
Causes and risk factors for throat cancer
Risk factors include:
- Infection with Human Papilloma Virus(HPV): Association of HPV-16 and other oncogenic HPV viruses is seen with oropharyngeal cancer, especially for carcinoma of tonsil. HPV associated cancers are found more in young patients, who are mostly non-smokers and non-drinkers
- Tobacco: It includes smoking tobacco by cigarettes, cigars & pipes and consuming smokeless tobacco by Snuffing and chewing.
- Excess consumption of Alcohol: Tobacco smoke and alcohol act synergistically in causing throat cancer.
- Infection with Epstein Barr virus ( EBV): Most commonly associated with cancer of the nasopharynx.
- Chewing Betel quid and areca nut: This is one of the most common causative factors of throat cancer in South-East Asia.
- Asbestos and wood dust: Exposure to these irritants increases the risk of cancer of hypopharynx.
- Plummer-Vinson syndrome: Associated with the cancer of hypopharynx.
- Diet low in vegetables and fruits.
- Exposure to radiation in the past
- Genetic factors.
Diagnosing throat cancer
Good clinical examination is the cornerstone for diagnosis of cancer of throat.
History & Examination:
- Global evaluation of general health and nutritional status.
- History regarding smoking and alcohol.
- Complete inspection and digital examination of all the sites of oropharynx
- Evaluation of throat using a flexible nasopharyngoscope and if needed may include a pan-endoscopy and examination under anaesthesia.
Evaluation of the throat cancer requires the use of special x-rays like computed tomography (CT) scan with contrast, magnetic resonance imaging (MRI) scan and/or positron emission tomography (PET) scan.
A small amount of suspicious growth in the throat will be sent to a pathologist for microscopic examination. This helps in confirmation of the throat cancer.
Testing for HPV:
Biopsy of the neck mass will be tested for certain viruses like human papillomavirus (HPV – common cause of cancer of oropharynx) and Epstein - Barr virus (EBV- common cause for cancer of nasopharynx). Testing will also be done for proteins related to these viruses (e.g. P16 – related to HPV infection).
This helps in evaluation of the swallowing.
Treatment for throat cancer
- The treatment goals are to preserve the form and function of the throat.
- Treatment for throat cancer includes surgery or radiation therapy or chemotherapy or a combination of these.
- The treatment modality depends on the site and size of the tumour and other patient factors.
- Treatment plan also depends on the involvement of the Human papilloma virus. Patients associated with HPV infection can be benefited from a less intensive treatment. Radiation therapy along with chemotherapy is more effective than the radiation alone.
- Advanced throat cancer patients need target based therapy or immune therapy.
- Swallowing and speech rehabilitation therapy should be provided after the definitive treatment.
Preventing throat cancer:
- Refrain from smoking and consuming any tobacco products.
- Avoid excess drinking of alcohol
- Take a balanced diet rich in fruits and vegetables.
- Maintain a healthy lifestyle.
- Reduce risk of HPV infection.