Because treatment often damages healthy cells and tissues, it may appear side effects. These side effects depend mainly on the location of the tumor and type of treatment. Side effects are not the same in different people, and they may even change from one treatment to another. Before treatment the doctor should explain the possible side effects and suggest ways to control them.

Surgery
The surgery requires a lot of time, but this time individually for each patient. It may be uncomfortable during the first few days after surgery. However, different drugs can reduce pain. Before surgery, you can discuss a plan to alleviate pain with a doctor or nurse. After surgery, the doctor can develop a plan to alleviate the pain.

Patients usually feel weak. Also, surgery can cause edema of the skin tissues. This swelling usually resolves within a few weeks. However, removing lymph nodes can cause swelling, which lasts a long time.
The surgery, at which removed a small tumor of the oral cavity, can not cause any long-term problems. For large tumors, however, the surgeon may remove part of the palate, tongue, or jaw. This surgery may change the ability to chew, swallow or speak. Also, a person may look different after surgery. Reconstructive surgery is used to restore the bone or tissue of oral cavity (See "Reconstruction").

Radiation
Almost all patients who underwent radiotherapy of the brain and neck area, can have side effects. It is therefore important that the oral cavity was in good condition before you start the treatment of cancer. It should be observed with a dentist before starting treatment.
Side effects of radiation therapy depend mainly on the extent of therapy. Some side effects of oral and disappear after radiotherapy, whereas other side effects continue for a long time. Some side effects (eg dry mouth) never pass.
Radiation therapy can cause some or all of these side effects:

• Dry mouth: Dry mouth can cause various problems, such as problems with swallowing. It may also lead to loss of teeth. You can drink plenty of water, suck on hard candy and sugar substitute to use saliva to moisten the mouth.
• Tooth decay: Radiation therapy can cause tooth loss. Good care of the oral cavity may help. The doctor usually advises that patients cleaned their teeth, gums and tongue with a soft toothbrush and toothpaste with fluoride, after each meal meals and at bedtime. If cleaning is painful, it is recommended to change your toothbrush. Your doctor may advise the use of gels containing fluorine, before, during, and after radiation therapy. It is also necessary to rinse your mouth several times a day with a solution: 1 / 4 teaspoon baking soda and 1 / 8 teaspoon salt in a glass of warm water.
• Sore throat or mouth: Radiation therapy can cause painful sores and inflammation. Your doctor may suggest different medications that help control the pain. Doctor and may offer special solutions for gargling and mouth to help reduce sensitivity. If the pain continues, you should consult your doctor about stronger medicines.
• Bleeding gums: It is important to brush your teeth with a soft brush. You can avoid areas that may be inflamed and bleed. To protect the gums from damage to avoid the use of toothpicks.
• Infection: Dry mouth and damage during radiation therapy may contribute to the development of infection. Should be reported to your doctor about any problems of the mouth.
• Radiation therapy may interfere with the healing of tissues of the mouth. Should be regularly screened with a dentist.
• The immobility of the jaws: radiation therapy can affect the chewing muscles. You can prevent or reduce the immobility of the jaw. Doctors often advise to make a series of exercises, for example, open and close his mouth by 20 times, 3 times a day.
• Problems with dentures: Radiation therapy can change the tissues of the mouth so that dentures are great. Because of the sensitivity and dryness of the mouth, some people are not able to wear dentures after radiotherapy. After the tissues heal completely, and oral cavity is no longer inflamed, your dentist may alter or replace dentures.
• Changes in taste and smell: During radiation therapy may be various changes in sensation of taste and smell of food.
• Changing the voice: A voice can weaken at the end of the day. On the voice may also be affected by the changes of weather. Radiation therapy directed at the neck, can cause swelling of the larynx, voice changing. Your doctor may suggest different drugs to reduce this swelling.
• Changes of thyroid cancer: Radiation therapy can affect the thyroid gland. If the thyroid gland does not allocate enough thyroid hormone, the patient may feel weakness, weight gain, feeling cold, and have dry skin and hair. The doctor can check the level of thyroid hormone through blood tests. If the level is low, you need to take pills that contain hormones of the thyroid gland.
• Changing the skin on the affected area: the skin on the affected area may turn red or become dry. Good skin care is very important at this time. It is useful to protect this area from the sun. Also, avoid wearing clothing that rubs the affected area. Do not use lotions or creams on the affected area without the doctor's advice.
• Fatigue: Patients may appear weak, especially in the later weeks of radiotherapy. Rest is important, but the doctor may advise patients to remain active.
• Although there may appear side effects from radiation therapy, the doctor can treat or control them. Should also report any problems with health, the doctor can control and reduce them.

Chemotherapy
Chemotherapy can cause some of the same side effects as radiation therapy, including painful mouth and gums, dry mouth, infection, and changes in taste sensations. Some anticancer drugs can also cause bleeding in the mouth and severe pain, which looks like a toothache. The problems depend on the type and quantity of drugs against cancer, which takes the patient, and how the body reacts to them. These problems can only occur during treatment or within a short period of time after treatment.

Generally, anticancer drugs affect cells that divide rapidly. These cells, but cancer cells are:

• Blood cells: These impacts affect the cells that are involved in the process of blood clotting, and carry oxygen to all parts of the body. When drugs affect blood cells, being more prone to develop infections and feels weak.
• The cells of the hair roots: Chemotherapy can cause hair loss. The hair will grow again, but sometimes the new hair is different in color and structure.
• The cells lining the oral cavity, abdomen and other parts of the digestive tract: Chemotherapy can cause poor appetite, nausea and vomiting, diarrhea, problems with swallowing or ulceration on the lips. Many side effects can be controlled with drugs.