Head and neck cancer usually refer to Neoplasms that arise from bottom skull base in the region of thoracic inlet. Structures in the head and neck are responsible for various important functions such as sight, hearing, smell, taste, deglutition and breathing. Any head and neck neoplasm arising out of these features. The other important aspect is the cosmetic disturbances that affect the individual psychologically and physically.
Head and neck cancer constitutes 5% of all cancers worldwide. It is more predominant in countries like South-East Asia, parts of Africa and South America and has a low prevalence in the United States and Western Europe. In India is the head and neck cancer the most common cancer seen in males in O.P.D. the most common head and neck cancer is in the oral cavity and throat. Age adjusted incidence in Indian males ranging from 10.8 to 38.8 per 1 lakh Indian females from males and 6.4 for 14.9 per 1 lakh females. Overall male and female ratio is 4: 1. Mouth and mucosæ cancers position as the third most common cancer in males and the fourth most common cancer in females. They are usually the fifth decade and more but salivary gland and nasopharynx tumour seen in younger age groups.
Radiotherapy treatment modality is largely used for head and neck malignancies. However, high doses of radiation in large areas, results including the oral cavity, maxilla, mandible and salivary Glands in the more adverse effects. Mucositis, candidiasis, dysgeusia, radiation caries, osteoradionecrosis, soft tissue necrosis and Xerostomia is common complications when radiation doses used. But with the advent of linear accelerators and by means of a technique, IMRT presence of these accessories can be drastically reduced.
Negative effects of radiotherapy depends on the volume and area will be irradiated, on the total dose fraction size, age, the patient's clinical conditions and their treatments. A small increase in tumor doses are enough to lead to a significant increase in complication incidence. Acute reactions happen during treatment and most of the time, they are reversible. Late complications are usually irreversible, leading to permanent incapability and to a deterioration in the quality of life and they vary in intensity, usually classified for mild, moderate and serious.
Many head and neck cancer patients sent to high doses of radiotherapy on large areas of radiation including the oral cavity, maxilla, mandible and salivary Glands. Anti-cancer therapy is associated with multiple adverse reactions. These reactions may occur in an acute stage (under or on the weeks right afer treatment) or in chronic phase (months or years after radiotherapy). The severity of acute oral complications depends on the degree of inclusion of these structures in the area of radiated.
Mucositis
Mucositis is defined as mucosal irritation. It starts to develop after the third week of treatment in most patients but patients who are heavy smokers, diabetics or hypertensive it can begin as early as the 1st week. It is painful and lead to significant morbidity. The are usually controlled by the pain killers and anti-inflammatory agents. Mucositis also leads to difficulties in swallowing which indirectly result in the improper food intake and weight loss.
Candidiasis
Radiation patients are more likely to develop oral infections caused by fungi and bacteria. These patients have higher nr. microbial species Lactobacillus species holocaust, Streptococcus aureus and Candida albicans. Oral candidiasis is a common infection in patients treated for upper respiratory tract and digestive tract malignancies. Colonisation of oral mucosa can be found in 93% of these patients, whereas Candida infection can be found in the 17-29% of patients submitted to radiotherapy. The possible explanation such high prevalence has fallen in salivary flow and reduced the phagocytic activity of salivary suspension of granulocytes against these micro-organisms. Clinical, candidiasis can be seen both in pseudomembranous and erythematous forms.
Dysgeusia
Dysgeusia affects patients from the second or third week in radiation treatment and may last for several weeks or even months. It occurs because the taste buds are radio-sensitive with the degeneration of their normal histological architecture. Increase salivary flow viscosity and saliva biochemical modification creates a mechanical barrier of saliva, which makes it difficult to physical contact between the tongue and foodstuff. It recovers about 3-6 months after the end of the radiation. Studies show that dysgeusia is a complaint from approximately 70% of patients submitted to radiotherapy, which also involves loss of appetite and weight, it will be most unpleasant complication for most radiated patients.
Radiation Caries
Even patients who had not experienced tooth decay for some time, can develop radiation caries when submitted to radiation therapy. The most important factor for the development of such damage is the decrease in the amount of saliva and its qualitative changes. Radiation also has a direct effect on the teeth, making them more susceptible to decalcification.
Osteoradionecrosis
Osteoradionecrosis is a bone ischemic necrosis caused by radiation, is one of the most serious consequences of radiation therapy, causing pain, as well as any significant loss of bone structure. In most cases is osteoradionecrosis associated with soft tissue necrosis also. This is exacerbated by trauma such as tooth extraction after radiotherapy. Mandibles are affected more than maxillas.
Soft tissue necrosis
It is defined as ulcer located in radiated tissues without the presence of remaining Malignancy. The presence of soft tissues necrosis is related to dose, time and intensity of the radiated gland when brachytherapy is used, the risks are higher. Soft tissue necrosis is usually painful condition and good oral hygiene along with the use of painkillers and often times antibiotics is necessary in order to manage the condition.
Xerostomia
Xerostomia or dry mouth is the most enduring morbidity Main and neck radiation. It is usually caused by exposure of both parotids. This leads to several complications such as recurring infections, inability to swallow solid foods, dental decay, taste loss, change in voice and speech and needs treatment with oral artificial saliva, taste stimulants and systemic agents such as pilocarpine or Bethanechol.
Prevention of oral Sequaelae: user technique, Imrt
IMRT assigns non-uniform intensities small subdivisions of beams called rays or beamlets. These enhanced dose distributions leads to enhanced tumor control and less normal tissue toxicity. Which requires the setting of IMRT relative intensities of tens of thousands of rays, which cannot be done manually, require specialized computer aided optimization methods. The main advantage of IMRT is in Parotid sparing and spinal cord sparing.
Worldwide data in 10 years has proposed IMRT be treatment of choice from Radiotherapy point of view. This saves parotid salivary glands and thus preserves the features in the majority of patients. It also leads to fewer doses, spinal cord and the patient has thus not radiation myelitis. Since it is a local treatment much of soft tissues and bone can be kept out of the box leads to fewer or negligible incidence of soft tissues or osteoradionecrosis.