In Hindi, the word 'Kiran' means the ray of light that chase away the darkness. A ray of light from the sun brings end to the night to bring out a new day to the world. A ray of light has many positive qualities. A ray of life always brightens one's life. That is why; the ray of light can be also called as the 'Ray of Life'. In the field of 'Cancer', this has been found very beneficial for the patients. Radiation Therapy is a boon to the modern world. It is a well known choice of treatment of the disease, so called 'Cancer', where the patients receive high dosed rays on the site of 'Tumour' to kill the cancerous cells. These rays are also a sort of light that can bring a new life to a cancer strucked patient. It is the 'Soul Treatment' in 'Head and Neck Cancers', which is highest in India's north east region.
The human body is built up of living cells. Normally the cells divide, mature and die. The division of cells is a highly regulated process. The process is controlled by the Dioxyribo Nucleic Acid or DNA. DNA is a complex molecule that serves as the brain of the cell. It is the blue print of everything that a cell does. In human cell, DNA is arranged in 46 Chromosomes and the chromosomes are arranged in 23 pairs. Altogether the 46 chromosomes contain 100,000 genes. A gene is a segment of DNA that determines the structure of Protein. It is needed for development, growth as well as to carry out other vital chemical reaction in a human body.
A cell divides when it receives proper signal from growth factors that is present in the blood stream. In case of Cancer the cells stray away from the programmatic physiological path. It grows and divides getting out of control, ignoring the signals to stop dividing. In a cancer cell, several genes undergo the process mutation making the cell to become defective. A gene mutation may allow an already abnormal cell to invade the normal tissue where the cancer started or to travel in the bloodstream to other parts of the body, where it continues to divide. The reason behind the mutation of cells is many. It may be due some infection, hereditary factor, climatic condition, food habits etc. A cell can become abnormal when part of a gene is lost or deleted, when part of a chromosome is rearranged and ends up in the wrong place, or when an extremely small defect occurs in the DNA, which results in an abnormal DNA "blueprint" and production of a defective protein occurs. This process takes several years.
Radiation Therapy is a type of cancer treatment where high dosed rays are used to shrink down a tumour or to kill the cancer cells. It is of two types. The first one is the External Beam Radiation Therapy where the rays are delivered, by a instrument outside the body. It is often delivered in form of Photon Beams. A photon is a basic unit of light and electro magnetic radiation. The external beam radiation therapy is delivered using a machine called Linear Acceletor. The second one is the Internal Beam Therapy, also known as Brachytherapy, where the rays come from radio active materials placed in the body near to the cancer cells. Several brachytherapy techniques are used in cancer treatment. Brachytherapy may be able to deliver higher doses of radiation to some cancers than external-beam radiation therapy while causing less damage to normal tissue. In brachytherapy, radioactive isotopes are sealed in tiny pellets. These pallets are placed in patients using delivery devices, such as needles, catheter, or some other type of carrier. As the isotopes decay naturally, they give off radiation those damages nearby cancer cells. The another one also exist, which is known as Systematic Radiation Therapy, where radio active substances are used to travel through the blood stream to kill the cancer cells. In systemic radiation therapy, a patient swallows or receives an injection of a radioactive substance. For example, radioactive substances like radioactive iodine that is used to treat many cancers in thyroid.
Radiation Therapy is advised to a patient in three conditions. The first one is may be advised before surgery which is known as Pre Operative or Neo Adjuvant. Neo adjuvant radiation is given to a patient to shrink a tumour, so that it can be easily removed through surgery. The second one may be advised during surgery. It is also known as Intra Operative Radiation Therapy. It can be either external-beam radiation therapy or brachytherapy. When radiation is given during surgery, nearby normal tissues can be physically shielded from radiation exposure. Sometimes it is used when normal structures are too close to a tumor to allow the use of external-beam radiation therapy. The third and the last condition may be Post Operative or Adjuvant radiation therapy. It is used to eliminate the residual disease after the surgery. Sometimes Chemo Therapy ( treatment using medicines) and radiation therapy are combined together as treatment. The combination is known as Chemoradiation Therapy, where the rays act as fire to burn the cancer cells and medicines as fuel.
Radiation therapy is sometimes used as Curative treatment. It is used with curative intend to cure a cancer by eliminating the tumour or preventing cancer recurrence. It is also used as Palliative treatment. During palliative treatments, it is not intended to cure the disease but for symptomatic relief and to low down the sufferings of the patient.
The radiation therapy prescribed by a specialist depends on many factors. All the factors includes Type of the cancer, Size of the cancer, Location of cancer in the body, Closeness of the cancer to normal cells that are radio sensitive, distance in the body that radiation needs to travel, General health and medical history of the patient, other sort on ongoing treatments, Age of the patient and other factors and medical conditions.
Along with the cancer cells, the rays destroy many healthy cells and tissues also. That is why it can cause both acute and chronic side effects. Acute side effects may occur during the treatment where as the Chronic side effects may be seen quite late after the treatment. Acute radiation side effects are caused by damage to rapidly dividing normal cells in the area being treated. These effects include skin irritation or damage at regions exposed to the radiation beams. Examples include damage to the salivary glands or hair loss when the head or neck area is treated, or urinary problems when the lower abdomen is treated. Most of the acute side effects disappear when the treatment ends, but sometimes symptoms like dryness of oral cavity due to damage in salivary glands or Xerostomia remains permanent. Chronic side effects of the radiation therapy can be hardly seen. It included problems like Fibrosis, Infertility, Memory loss or damage in bowels causing bleeding or diarrhea. Proper Nutrition, mostly protein rich diets are necessary for a patient receiving rays to build up the damaged healthy cells and tissues. Other medications prescribed by the Doctor should be followed always to fight the side effects.
(A part of Project Kiran,
Reference: National Cancer Institute, USA)
By: Dr. Gitartha Roymedhi,
Medical Officer,
North East Cancer Hospital and Research Institute.
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