Barah Mulut & Barah Lidah

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Cancer of the mouth and tongue

By Dr PAUL LIM VEY HONG

There are multiple factors that increase the risk of mouth and tongue cancer.

IN August 2010, Hollywood was abuzz with news that celebrity and veteran actor Michael Douglas, had been diagnosed with stage IV throat cancer. Catherine Zeta Jones, Douglas’ wife, was reported to be furious that the cancer was diagnosed at an advance stage as her husband had been going to his doctors complaining of sore throat and ear pain for months. Eventually, a tumour the size of a walnut (approximately the size of a duku in local terms), was discovered in Douglas’ tongue base and he was offered treatment with radiotherapy and chemotherapy. Douglas later appeared on the David Letterman show to talk about his cancer and Letterman remarked, “You look great Michael, you don’t looked like you have stage IV cancer.”

(There is a part of the tongue that actually lies in the throat and can only be wholly visualised with special instruments by specialist doctors. – Reuters)

In fact, no one afflicted with cancer ever “looks” like he or she has cancer, not even those with stage IV cancer. Cancer can only be detected after a thorough medical consultation, examination and performing a biopsy on the growth or area of the body affected.

Tracing clues

Traditionally, cancers of the mouth and tongue have been associated with tobacco smoking. Other risk factors include excessive alcohol consumption and the chewing of betel quid. The latter is a practice prevalent among communities stretching from the Indian subcontinent, across South East-Asia to as far away as Taiwan. Betel leaf (daun sirih), together with aracea nut, collectively known as the betel quid, is mixed with mineral slaked lime (calcium hydroxide) and chewed. When combined with tobacco to chew, this has a higher risk towards the development of mouth and tongue cancer.

This was commonly practiced by rural folk, in particular estate workers, of bygone eras, which explained the high incidence of oral cancer among elderly estate workers. Another risk factor is chronic irritation of the lining of the mouth or edges of the tongue with the ragged or sharp edge of a tooth. Long term poor oral hygiene is another contributing risk factor. Chronic inflammation of the lining of the mouth, a condition known as lichen planus, is another known risk factor. In recent years, there appears to be an emerging group of young adult sufferers of these cancers who are aged between early 20s to mid-50s, who have never used tobacco, drunk alcohol, chewed betel quid or have any of the above risk factors. The latest research has revealed that some of these cancers are due to viral infection with the Human Papilloma Virus 16 (HPV 16). Interestingly, this virus is also associated with cancer of the cervix in women for whom vaccines are currently available to protect against HPV infection, hence reducing the risk of cervical cancer. Evidence from research also showed that smoking and alcohol help to promote HPV invasion of healthy cells, thereby increasing the risk of cancer development.

Pathology

Cancers of the mouth frequently develop on the lining of the cheeks (which can easily be seen). Not infrequently, it starts in an area at the back of the mouth right behind the last lower molar or “wisdom-tooth”. Cancer in this area is less easily spotted. Being hidden from view behind the last molar tooth and because of its close proximity to the tongue and throat, these cancers have a tendency to spread undetected. Patients with these cancers tend to detect the growth later. This area is known among doctors as the retro-molar trigone, and is frequently (and infamously) referred to as “coffin triangle”. Not infrequently, cancers also develop in either tonsil at the sides towards the back of the mouth. Less frequently, cancers of the mouth develop in the roof of the mouth and also on the lips. The tongue that we see when one opens his or her mouth is only the front two thirds of the whole tongue. The remaining third of the tongue, the posterior third or tongue base, cannot be seen. If the front of the tongue is protruded sufficiently, one will see some small discrete lumps of about 2 to 4mm in diameter at the back, starting at the edges on both sides of the tongue and forming a row of lumps to meet backwards at the centre, thereby creating an inverted “V”, just before the entrance into the throat. These lumps (called the circumvallate papillae) are taste buds and are frequently mistaken to be “growths”. The part of the tongue behind these taste buds is the tongue base. This part of the tongue actually lies in the throat and can only be wholly visualised with special instruments by specialist doctors. I suspect this was the reason why Douglas’ tumour could reach stage IV before it was detected despite him seeking medical advice earlier. Tongue base and tonsil cancers are frequently associated with HPV 16 infection. Cancers of the front or anterior two thirds of the tongue usually develop at the sides or edges of the tongue. They start as small ulcers or lumps at the sides of the tongue and progressively enlarge. Any ulcer or lump of the tongue and mouth that doesn’t heal or go away after one month must be seen and examined by a doctor or specialist to rule out cancer. Diagnosis is achieved by a biopsy of the ulcer or lump. This involves taking some tissues from the ulcer or lump under local anaesthesia and sending the sample to a pathologist for examination. The pathologist will decide whether the sample of tissue shows characteristics of cancer and this will determine the next step of treatment.

Types of cancer

There are several types of cancers of the mouth and tongue. The vast majority of these cancers are of the squamous cell types. There are other forms too and these could range from adenocarcinoma (more commonly found in breast, stomach and colon), adenoid cytic carcinoma, melanoma (more commonly seen in skin) and lymphoma (a form of cancer of lymph nodes). The squamous cell type tends to respond to treatment with radiotherapy more than the other types. These are all aggressive cancers which will invade into neighbouring tissues (metastasise) and spread to other parts of the body such as lymph nodes in the neck, lungs, liver, bones, etc. As there is a rich network of lymphatic drainage from the head to the neck, it is therefore not surprising that up to 60% of mouth and tongue cancers have metastases to the lymph nodes on their sides in the neck when the cancer is first detected. The larger or more advanced the cancer, the higher the likelihood of neck lymph node metastases. These metastases in the lymph nodes of the neck may not be obvious or detectable initially, but with time, they reveal themselves at lumps in the neck which enlarges with time. Fortunately, metastases to the rest of the body, such as the lungs, liver and bones, occur later. It is therefore highly advantageous to detect the cancer as early as possible, before it spreads, or while it is still in its earlier stages, so that the appropriate treatment can be carried out with the best possible result.

Treatment

Treatment of cancers of the mouth and tongue can be broadly divided into surgery, radiotherapy and chemotherapy. Surgery involves removing the cancer of the mouth or tongue and the affected lymph nodes in the neck. The defect created in the mouth or tongue after removal of the cancer must be “repaired” or reconstructed, to enable the patient to be able to eat, swallow and speak. Besides function, the cosmetic appearance after the surgery is also an important factor to be considered and it must be acceptable to the patient, who has to live with it. Reconstruction can be as simple as sewing up the defect after a small cancer has been removed. Larger defects will require the use of skin harvested from other parts of the body, such as the outer thigh area. Skin and muscle from the chest wall can be used to reconstruct part of the tongue which has been removed for cancer. Skin, fascia and bone from the wrist region can be used to reconstruct larger defects of the mouth where the cancer has invaded into the jaw bone. The duration of surgery for cancers of the mouth and tongue can therefore range from being less than an hour to as long as twelve to sixteen hours! The latter is usually reserved for the more the aggressive, larger, deeply invading or advanced cancers. This form of surgery is more commonly known as the “commando” operation. How the “commando” name came about to be associated with this form of radical and extensive surgery remains a mystery, but it certainly does not infer to the bravery of the surgeon doing the surgery or the patient undergoing it. The most credible version was that the name was coined by a trainee who found it too tedious to write out the name of the surgery in full, ie. Combine Oral-Mandibular and Neck Dissection, and creatively abbreviated it as “commando”. This form of surgery is not infrequently performed in this country as a significant percentage of advanced mouth or tongue cancers have a much better outcome when dealt this way as opposed to other alternative forms of treatment available. Cancers of the mouth, tongue and tonsil that have recurred after earlier treatment with radiotherapy are also cases suitable for this form of surgery. The mortality rate from this surgery is very low in patients who are fit, as determined by medical check-ups before the surgery. The oldest patient who has undergone this operation with a good result is in his late 70s and is still working currently. Sometimes, the location of the cancer or extent of the cancer may make surgery a lesser preferred option, namely because of the side effects. Large cancers of the tongue base are such examples. Any attempts to remove these cancers may leave patients with difficulty or inability to swallow and speak after surgery. In such instances, radiotherapy combined with chemotherapy are employed to treat the cancer. Advanced cancer with poor prognosis is another example whereby radiotherapy and chemotherapy are employed instead of surgery. Different types of cancers respond to radiotherapy differently. The squamous cell cancers are more responsive to radiotherapy than other types. Cancers due to HPV 16 infection are also more responsive to radiotherapy. Tissues taken from cancers during biopsies can be analysed for HPV 16 infection to determine its responsiveness to radiotherapy. In HPV 16 positive cancers of the mouth, tonsil and tongue, radiotherapy is the preferred option of treatment.

Radiotherapy involves the use of ionising radiation generated by machines, called linear accelerators, to treat cancers in the mouth or tongue. It can be used as a form of treatment with “curative intent” or with “palliative intent”, where cure is no longer possible and the aim of treatment is to control the cancer locally or provide symptom relief. Patients undergoing surgery may also receive radiotherapy as part of their treatment, before, or after the surgery. Some patients receiving radiotherapy will also receive chemotherapy. A unique form of radiotherapy treatment involves the insertion of radioactive implants into the cancer to eradicate it. This is called brachytherapy. It is only suitable for small cancers of the tongue. Radiation therapy will damage both cancer cells as well as normal cells. Treatment is therefore planned and staggered carefully to minimise side effects. The side effects of using radiotherapy to treat mouth and tongue cancers are sore throat during treatment, scarring of treated tissues, which can affect wound healing if surgery is undertaken later, and dryness due to loss of saliva, which may be permanent. Radiotherapy and chemotherapy are administered by oncologists. Chemotherapy involves the use of cytotoxic drugs which are lethal to cells that divide rapidly, one of the main characteristic of cancer cells. While cytotoxic drugs can kill both cancer and healthy cells, the healthy tissues recover after the cytotoxic drugs are given in staggered doses (in cycles) to kill off cancer cells preferentially.

Like radiotherapy, chemotherapy can be given with either curative intent or palliative intent. Because the drugs are administered into the body, usually by an intravenous drip or via a device that accesses the blood stream, the side effects are more generalised than the localised effects of surgery or radiotherapy. Side effects can range from problems of nausea, vomiting, loss of appetite, due to mucositis or inflammation of the lining of the digestive tract, and tiredness, to more pronounced effects of hair loss (alopecia), infertility, serious bone marrow problems (mylosuppression) causing anaemia, low white cell count causing weakness in the immune system in fighting infections, and low platelet count, which can lead to serious internal bleeding. The serious side effects are usually avoidable by tailoring the chemotherapy treatment specifically to each patient. There are also medicines available to reduce the toxic effects of the cytotoxic drugs and they are given at the same time as the chemotherapy.

Seeing the right doctor

Patients frequently ask, “Who should one see for mouth or tongue cancer?”

My answer is any one of these three: an ear, nose, throat, and head and neck surgeon, oral/maxillofacial surgeon, or oncologist. Generally speaking, specialists with interest in treating oral and tongue cancers or any other forms of head and neck cancers tend to work closely and inclusively. This means that we tend to consult one another to seek each others’ opinions to decide on the best option before embarking on the treatment, be it via surgery, radiotherapy, chemotherapy, or a combination of two or even all three of these modalities mentioned.The two main goals of treatment are to eradicate the cancer with the minimal possible side effects, and to do so with the minimal chance of the cancer coming back later. I frequently teamed up with an oral surgeon, and at times, with a plastic surgeon, when performing the more extensive or radical forms of surgery. In many instances, patients are also seen by an oncologist before or after surgery for consideration for radiotherapy, chemotherapy, or even both. “Why use more than one form of treatment? Doesn’t this cause more side effects for the patient?” These are the questions frequently asked by the relatives. The reasons to employ more than one form of treatment where deemed necessary is to remove the cancer completely, prevent it from metastasising or spreading elsewhere and to prevent it from coming back. While side effects cannot be totally prevented, they are usually temporary. Patients can recover and heal to deal with the side effects when the cancer has been eradicated. Without treatment, the survival rate of mouth or tongue cancer is zero. With treatment, the five year survival rate is 80% to 90% for early cancers of mouth and tongue, and this decreases to 40% for advance cases. Last but not least, I read in the papers on January 15, 2011, that Douglas had announced that the walnut-size cancer of his tongue base has resolved after completing his radiotherapy and chemotherapy. Let’s hope that he is on the road to a full recovery.

Dr Paul Lim Vey Hong is a Consultant ear, nose and throat specialist, head and neck surgeon. This article is contributed by The Star Health & Ageing Panel, which comprises a group of panellists who are not just opinion leaders in their respective fields of medical expertise, but have wide experience in medical health education for the public. The members of the panel include: Datuk Prof Dr Tan Hui Meng, consultant urologist; Dr Yap Piang Kian, consultant endocrinologist; Datuk Dr Azhari Rosman, consultant cardiologist; A/Prof Dr Philip Poi, consultant geriatrician; Dr Hew Fen Lee, consultant endocrinologist; Prof Dr Low Wah Yun, psychologist; Datuk Dr Nor Ashikin Mokhtar, consultant obstetrician and gynaecologist; Dr Lee Moon Keen, consultant neurologist; Dr Ting Hoon Chin, consultant dermatologist; Prof Khoo Ee Ming, primary care physician; Dr Ng Soo Chin, consultant haematologist. For more information, e-mail starhealth@thestar.com.my. The Star Health & Ageing Advisory Panel provides this information for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star Health & Ageing Advisory Panel disclaims any and all liability for injury or other damages that could result from use of the information obtained from this article.