Oral cancer is the sixth most common cancer in the world. It accounts for more than 3, 00,000 new cas-es and 1, 45,000 deaths registered annually. India accounts for one-fourth of all oral cancers world-wide. It is the most common cancer in males in India.
More than half of these patients die of the disease, because they present late. By contrast, early diag-nosis and treatment is associated with a good outcome. Late detection makes more radical treatment necessary, leading to increased morbidity associated with loss of function, aesthetics and psychologi-cal problems. Since oral cancers are readily detectable and identifiable at an early stage it should be possible to improve detection and hence the prognosis.
Oral cavity is made up of many types of cells. When cells divide in an abnormal, uncontrolled way, they can form a non-cancerous (Benign) or cancerous (Malignant) tumours. Oral cancer typically spreads through the lymphatic system to the lymph nodes in the neck.
Although the aetiology of oral cancer is complex, most Western studies have implicated tobacco smok-ing and alcohol drinking as the major cause of this disease. But in South Asia, in addition to the above factors, chewing of tobacco, betel nut and “pan masala” seems to be the main cause of this problem. Repeated trauma from a sharp tooth or ill-fitting denture may promote neoplastic change over a long period of time.
While the majority of oral cancers arise from a clinically normal mucosal lining, some oral cancers are preceded by pre-malignant changes. They may appear as white patches (Leukoplakia) (Fig.2) or red patches (Erythroplakia) (Fig.3). These may be caused by chronic trauma from sharp tooth or ill-fitting dentures or chemical irritants (tobacco, betel nut etc).
Another condition very common among Indians is known as sub mucous fibrosis (Fig.4). This is caused by chronic irritation from tobacco juice and pan masala. The lining of whole of mouth and throat are exposed to this irritation, resulting in fibrosis (scarring) underneath the mucosa. The mouth looks pale and the mouth slowly closes due to scar contracture. They are unable to open the mouth, always have a burning sensation in the mouth and have a tendency to develop cancer in multiple areas. Response to radiation therapy is also poor because of poor blood supply in the scarred areas.
Fig.4. Submucous fibrosis
If a patient has any of these symptoms for more than 2 weeks, they should see a doctor. Pain is not an early symptom. A tiny spot, ulcer or small lump should not be ignored, especially if a person is a smoker or drinker.
After complete clinical examination, the doctor may recommend CT scan or MRI scan or an endoscopic procedure to know the extent of the growth and the structures it is involving. PET scan is done not only to know about the locoregional disease but also to find out whether the disease has spread to other parts of the body.
Incisional or punch biopsies are done under local or general anaesthesia. Fine Needle Aspiration Cytology (FNAC) of the enlarged gland in the neck is done rather than open biopsy to know whether the tumour has spread to the glands.
Also known as mouth cancer, oral cancer typically starts as an ulcer or patch in the mouth
Nearly half of all head and neck cancers are found in the mouth and throat. Treatment for head and neck cancers may change the way person looks, breathes, talks, eats or swal-lows. Therefore multidisciplinary team approach to patient care is so important. The team includes:
The treatment options are surgery, radiation therapy and chemotherapy either alone or in combination depending on the stage of tumour. In choosing a treatment plan, factors to consider include overall physical health, the type and stage of cancer, the probability of curing the disease, and the impact of treatment on functions like speech, chewing and swallowing. Surgery or radiotherapy or both modalities combined is usually the most ap-propriate treatment form for curative intent. Chemotherapy is mostly reserved for patients with very advanced cancers.
If the patient undergoes surgery for oral cancer, the surgeon may remove the cancer and some of the healthy, adjoining tissue. Complete surgical clearance of the tumour is achieved with the help of the pathologist who examines the removed tissue at the time of surgery itself (Frozen Section) and says whether the removal was complete or needs fur-ther removal.
Fig.7. Rim resection of mandible. Only the shaded upper half of bone bearing teeth is re-moved. No need to reconstruct the bone.
Small tumours of the oral cavity can be quickly and successfully treated by surgical exci-sion, leaving behind little cosmetic or functional change (Fig.7). Among the advantages for treating early stage cancer with surgery is that it is completed quickly usually requiring a few days of hospital care, instead of 6 weeks of daily Radiotherapy. Dryness of mouth and radiation induced damage to teeth can be avoided. Most importantly, if the patient subsequently develops another cancer in the mouth, throat or voice box, radiotherapy would still be available as treatment option. This will avoid a more significant and disfigur-ing operation. When the index of suspicion is high that there may be cancer cells present in the lymph nodes, an operation called a neck dissection is performed.
Fig.8. Segmental mandibulectomy. Shaded area of bone is removed. Needs reconstruc-tion of bone.
For large primary tumour, after resection of the tumour (Fig.8), at Apollo Cancer Centre, the resected areas are reconstructed using microvascular technique.
The lower jaw bone (mandible), which gives shape to the lower part of the face, is essen-tial for chewing food. This bone is removed when the tumour invades it. If the bone is not reconstructed, chewing food is difficult and the facial appearance also changes. Current-ly, the lower jaw is reconstructed with a bone from the leg (fibula) using microvascular technique. It helps in retaining the facial contour and the patient is able to chew well with the remaining teeth. Teeth can also be fixed onto titanium screws that are implanted into the bone either at the time of the primary surgery or later ( known as Osseo-integrated dental implants). VIDEO 01 Removal of fibula bone from the leg does not change the ap-pearance or function of the leg.
the defect is immediately reconstructed using microvascular technique (Fig.10a & b) to improve speech and swallowing VIDEO 02.
Some of these tumours can extend to involve the muscles used for chewing/mastication (pterygoid muscles) in infra temporal fossa. It was considered inoperable and therefore incurable. They were receiving palliative treatment. In the last 2 decades, considerable progress is made in resecting these tumours. This has improved the survival in these pa-tients.
Regular follow-up examinations are very important for anyone who has been treated for oral cancer. The doctor will watch the patient closely to check the healing process and to look for signs that the cancer may have returned. Patients with dryness of mouth from ra-diotherapy should have regular dental examination. The patient may need to see a dieti-tian if weight loss or eating problem continues. Oral cancer patients are strongly advised to stop using tobacco and limit alcohol intake to reduce the risk of developing another cancer.
