Radiation Treatment.
Radiation in oncology or radiation in cancer forms a very important part of cancer treatment. Radiotherapy may be used alone or in combination with cancer surgery or with chemotherapy or with both to cure cancer. Though radiation treatment has its side effects, it has done more good than harm in the treatment of cancer.
Radiation Therapy.
More than 66% of cancer patients are given radiation therapy for their malignancy, either for cure or to give symptomatic relief. That means, more than one million cancer patients are given radiation treatment every year. This radiation statistic only signifies the importance of radiation in cancer therapy.
Types of Radiation.
About forty percent of cancer patients are given radiation therapy for their malignancy, either as treatment or to give symptomatic relief. Also referred to as radiotherapy for cancer, it can be either external radiation or internal radiation. Each of these types of radiation have their indications and sometimes both types of radiation may be used to cure the patient.
Internal radiation for cancer, also called brachytherapy, involves placing of an implant or “seed” containing radioactive isotopes inside the tumor or near it. The patient is required to be hospitalized for this radiation treatment for cancer.
External radiation for cancer makes use of a radiation machine to give radiation treatment from the outside, to the patient.
Image showing brachytherapy.
What is Radiation.
Radiation for cancer involves use of high energy ionizing radiation rays to target destroy the cancer cells and stop their uncontrolled growth. X-rays, Gamma rays and Charged particles are used for radiation in treating cancer.
How Radiation Works.
Radiation destroys the genetic composition (the DNA) of the cancer cells, thereby making it impossible for them to grow and multiply. This is done either by a direct destructive action on the DNA or by creation of free radicals inside the cancer cells, which destroy the DNA. The draining lymph nodes are also targeted if there is the slightest suspicion of their involvement. This procedure is performed by a trained radiation oncologist and is painless.
Besides the cancer tissue, the neighboring healthy tissue also gets destroyed due to radiation. The healthy tissue cells, however recover after radiation and begin their normal function. To allow time for the normal cells to recover, radiation is given at intervals.
Giving radiation has to be precise. Digital radiological reports of radiological studies( such as CT scans, MRIs, PET, ultrasound ) are referred to before treatment, to chalk out the area to be radiated. Exactly the same area has to be targeted at each radiation treatment. The patient has to be in the same position and angle. Skin marks or skin tattoos are used to mark out the area for the purpose.
Radiation for cancer is used for almost all tumors such as tumors of the brain, lung, breast, uterus, cervix, prostrate, pancreas and stomach. This treatment is also useful to treat lymphoma and leukemia.
Image of radiation therapy equipment.
Indications of Radiation for Cancer.
In treating cancer,
- Radiation may be used before cancer surgery to shrink the tumor for better results of surgery. This radiation therapy is called neoadjuvant radiation.
- Radiation may be given during surgery. This is called intra operative radiation and is indicated when the normal tissues close to the tumor, are extra sensitive to radiation and cannot be risked to radiation exposure. At such times, the normal tissue close to the tumor are covered and shielded from radiation to avoid damage to them. The tumor is the radiated.
- Radiation may be given after cancer surgery, for better prognosis. This is called post operative radiation or adjuvant therapy.
- Radiation is at times, also used alone in treating cancer.
- Most of the times, radiation for cancer is used in combination with chemotherapy for treating cancer. Though more cancer cells are destroyed with this therapy, the side effects are also more. This type of cancer therapy is called chemoradiation.
- At times, radiation for cancer is used as palliative treatment for giving symptomatic relief to the patient. Such examples are metastasis to the brain, spinal cord compression due to a tumor and occlusion of the esophagus by a tumor.
Unit of Radiation.
Doses of Radiation for cancer is measured in unit called gray. One gray is the amount of radiation that is absorbed by one kilogram of human tissue. Doses of radiation differ depending on the indication of radiation.
Dose of Radiation depends on the following data.
- General condition of the patient.
- Type of cancer tumor.
- Stage of Cancer.
- Sensitivity of the type of tumor to radiation.
- Sensitivity of the normal tissue adjacent to the tumor.
- Whether radiation is being given for cure or prevention.
Fractionation.
Fractionation is giving radiation therapy over intervals of time. Radiation is normally given at weekly intervals, but there may be variations as required. Radiation therapy is spread out with the purpose of giving normal tissue that has been damaged during radiation, time to recover.
Next: Side Effects of Radiation.
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