Cancer can be treated by any or all the following methods depending upon the site and the stage of the disease.
1. Surgical removal
2. Radiation therapy
3. Chemotherapy
4. Hormonal therapy

Which method should be used in a particular case, depends essentially on:

1. The type of cancer, and
2. The stage of the disease when diagnosed

It is necessary to see and recognize the cancer cell before a decision can be taken about the method of treatment. Some cancer cells respond to radiation, others don't; some cancer cells respond to one drug, others to another; many cancer cells respond better to a combination of drugs.

The stage of the disease at which a patient presents himself to the doctor, is very important in deciding the line of treatment. This is because survival rates are better for cancers that are loca1ised or at primary stage than for those which have spread or at secondary stage.                               

The internationally recognized staging system is known as the TNM classification in which T defines the extent of the primary tumor, N defines the extent of the regional lymph node involvement, and M defines the presence or absence of metastases.

The patient's history and physical examination provide a starting-point for planning treatment. It is usually necessary to perform specialized investigations to determine the type of cancer and extent of its dissemination or spread prior to selecting the treatment process.

Surgery
Surgery is usually indicated in cases of localized cancers. It may be done either alone or in combination with other lines of treatment such as radiation and chemotherapy.

If the cancer has not infiltrated into the surrounding areas and has not spread from the original site to different areas, then surgery may be all that is necessary. All the cancerous tissue has to be removed. In the process, even if a doubtful normal adjacent part is to be excised or surgically removed, this is done for the sake of safety and to prevent the recurrence of the cancer. The lymph glands enlarged or even suspicious, draining the area of cancer, are also resected or surgically removed.

Surgery is also resorted to in cases where the cancer is inoperable because of spread. This is done in order to remove any obstruction in a vital part of the body such as the intestines or bronchi of the lungs.

Surgery is also undertaken sometimes so that the patient is saved from very severe pain.
Radiation
Radiation involves the exposure of a selected area of the body to a source of ionizing radiation or X-rays under carefully controlled conditions. Treatment planning involves accurate localization of the cancer and calculation of the total radiation dose to be given and dividing the same into daily fractions over a period of some days or weeks so that there is optimum response and minimum side-effects.

The calculation is done by the radiation therapist by taking care of all the facts of the case, including how sensitive to radiation are the cancer cells of a particular patient as diagnosed by a pathologist from a biopsy specimen. The measurement of the radiation given is counted in units called rads (radiation absorbed dose), i.e. the radiation absorbed by the tissues.

Small fractions of radiation given in divided doses over a period of many days or weeks, do less harm to the nO1D1al cells.

Radiation damages cells by interaction with DNA present in the nucleus of the cells thus preventing the normal reproduction of that cell. Fast-dividing cancer cells are more susceptible to being killed than the normal cells. The normal cells are also damaged in the process to some extent.
Chemotherapy
Chemotherapy is the prevention or treatment of disease by the use of chemical substances. The te1D1 is sometimes restricted to the treatment of infectious diseases with antibiotics and other drugs or to the control of cancer with antimetabolites (that prevent cell growth) and similar drugs.

During the Second World War, research into the various aspects of the action of mustard gas which is ordinarily poisonous showed that this along with sulphur could destroy dividing cells in lymph nodes and the bone marrow. This harmful effect was harnessed to man's use for treating some lymphomas with nitrogen mustard. Thus was discovered the first cytotoxic drug against cancer, which damages or destroys cancer cells by inhibiting cell division.

Thereafter many naturally occurring substances were tested for anti-cancer activity on experimental animals resulting in the present availability of some 30 effective anti­cancer drugs.

Anti-cancer drugs are the treatment of choice for many widely disseminated cancers and serve as adjuncts to surgery and radiation in the treatment of localized ones.

The success of the various combinations of chemotherapy agents used in the treatment of some cancers, has brought hope to the patients.

Unfortunately, these drugs also affect normal cells particularly in bone marrow, skin, stomach lining, and foetal tissue and damage or destroy them, to some extent, resulting in many side-effects which are fairly serious. That is why the search for ideal anti-cancer drugs continues.

Hormonal Treatment of Certain Cancers
Cancers which develop in organs that are known to be under hormonal control, sometimes retain hormonal dependency. Withdrawing the source of the hormone in some such cases, lessens the growth of cancer. Cancers of the breast, prostate, uterus and thyroid are the ones amenable to hormonal treatment.

Previously, the adrenal glands or the pituitary gland were removed surgically for this purpose. But now the same effect is produced by medical rather than surgical means. Cancer response to Tamomen and Aminoglutethamide may take 6 to 12 weeks to manifest. Hence, it is necessary to wait for this period before making decisions about further management.

Androgen the male sex hormone may produces response in about 20 per cent of patients with breast cancer) particularly in post-menopausal women with bone metastasis. Oestrogen the female sex hormone is useful in the palliation of prostate cancer.

Some cancers of the thyroid remain under the influence of thyroid-stimulating hormone (TSH) and the administration of thyroid hormones may be useful as a result of its inhibiting pituitary secretion of TSH.

The major advantage of hormonal therapy over chemotherapy is that the side-effects are usually less severe than those associated with cytotoxic drugs. Tamoxifen rarely causes toxicity but aminoglutethamide can cause drowsiness depression and transient skin rashes in some patients. The use of oestrogen in elderly men with prostate cancer warrants special caution in view of its known propensity to aggravate the fluid retention that may be harmful to the patients also suffering from a. heart disease.