& çâÌæÚUæð´ ·¤è ¥ôÚU Îð¹Ùæ ÁæÚUè ÚU¹ð´ ¥ÍæüÌ ¥ÂÙð ÜÿØ ÂÚU ŠØæÙ ÚU¹ð´Ð ãæÚU Ù ×æÙð´, €UØô´ç·¤ ·¤æ× ·¤ÚUÙð âð ¥æÂ·¤ô ©gðàØ ·¤è Âýæç# ãôÌè ãñ ¥õÚU ÁèßÙ ·¤æ ¹æÜèÂÙ ÎêÚU ãôÌæ ãñÐ ÖÜð ãè ÁèßÙ ×ð´ ç·¤ÌÙè Öè ·¤çÆÙæ§ü €UØô´ Ù ¥æ°, çÁ™ææâæ ¥õÚU ©ˆâæã ÕÙæ° ÚU¹ð´Ð ŠØæÙ ÚU¹ð´, ÜÿØ ã×ðàææ ¥æÂ·Ô¤ Âæâ ãôÌð ãñ´ çÁ‹ãð´ ÂæÙð ·Ô¤ çÜ° ÂýØæâ ¥æÂ ·¤Öè Öè àæéM¤ ·¤ÚU â·¤Ìð ãñ´Ð

Radiotherapy in the treatment of cancer

DR PARVEEN SHAHIDA AKHTAR
Cancer is one of the major health problems in Bangladesh now a day. According to the Bangladesh Cancer Society about one million people are suffering from cancer and every year about 0.2 million people are newly diagnosed. Among the males lung, larynx, oral cavity and oropharynx, gastrointestinal tract are the common sites of cancer and in females uterine cervix, breast, oral cavity & oropharynx, ovary and gall bladder are the commonly affected organs. Children are suffering mainly from leukemia, lymphoma (cancer of lymph nodes), retinoblastoma (cancer of retina), brain tumor and sarcomas (cancer of soft tissue). Generally, the patients in our country present at an advanced stage of their diseases due to ignorance, illiteracy, poverty, superstition, treatment by quack and other causes.
Radiotherapy or radiation therapy is one of the important modalities to fight against cancer and is applicable to more than 80 percent of the cancer patients in our country at present situation. The aim of radiotherapy is to cure the cancer or to palliate (relieving the symptoms) the incurable disease prolonging the survival with better quality of life.
This treatment is used as single modality or in combination with other modalities like surgery and chemotherapy (therapy by some chemical agents and drugs).
The weapons of radiotherapy are the ionising radiations that are the invisible energies. The energies are x-ray, gamma ray and the particles such as electron, proton, and neutron. The sources of radiations are x-ray machines, linear accelerators (from where different energies like x-ray, electron, proton and neutron are generated), differ- ent radioactive isotopes such as Cobalt60, Caesium137 and Iridium192 (automatically emits gamma rays). In a simple word, these are the nuclear energies, used for the treatment of cancer.
There are two ways for the application of radiotherapy, namely external beam therapy or teletherapy and internal therapy or brachytherapy. In teletherapy treatment, the source of radiation is kept at a certain distance from the body but in brachytherapy the source is placed in close contact or inside the cancer affected organ. The teletherapy machines are Cobalt60, Linear Accelerator etc. and brachytherapy machine contains radioactive isotopes. Different isotopes are used for brachytherapy such as cobalt60, caesium137 and irridium192. Radium was the first isotope used for brachytherapy beginning about 100 years ago but now a days the use of this isotope has become obsolete.
Radiotherapy treatment, especially teletherapy is usually a lengthy treatment. In accordance with the international practice, the total dose is divided in fractions usually with five days treatment per week, up to a total of four to seven weeks period or more. But the treatment time per day is very short, some times even only a fraction of a minute. In case of diseases not fully curable, the period of treatment may be shorter, but it depends on many different factors. The treatment time of brachytherapy depends on dose
rate of brachytherapy source and some times the treatment is given in combination with teletherapy. In case of high dose rate brachytherapy, the treatment time may be a few minutes and can be given on outdoor basis but for the optimised dose several applications are needed. In low dose rate brachytherapy, the treatment time may be 20- 25 hours or more but for optimised dose one or two applications are sufficient.
The need of optimized treatment
Radiotherapy should be optimised in all respects. Wrongly executed radiotherapy treatment can never be corrected. So, before starting actual treatment, a trial is carried out by checking the actual site of treatment and confirming the distribution pattern of doses of radiation in the radiation field. There are several associated machines and arrangements, which are necessary for the optimised therapy. A simulator is a machine used for localisation of the radiotherapy treatment field. Computer planner is used for treatment planning and to see the dose distribution pattern of radiotherapy. The arrangement of fixation of the patient during treatment is very important so that everyday every fraction of treatment can be carried out in the same way.
Success of the treatment depends on execution of optimised radiotherapy. Complete eradication of cancer can be possible by the optimised dose. Overdose is harmful and cause damaging effects rather than giving any benefit. On the other hand in case of under dose there remains residual tumor, which continues to grow again, ultimately leading to the patient's death.
How to execute the optimized radiotherapy treatment?
Radiotherapy is a co-ordinated teamwork. The radiation oncologist (doctor specialised in radiation oncology) is the team leader. The radiotherapy is carried out in three steps.
First step is the treatment planning that depends on the patient's general condition, diagnosis, disease stage, site of treatment, total dose, dose per fraction, selection of machine and many other things. Radiation oncologist bears the over all responsibilities of radiotherapy treatment of the patients.
Second step is to keep of all the radiotherapy machines proper functioning. Medical physicist (trained personnel in this field) ensures the accuracy of the radiation dose in the patent and is responsible for the radiation protection of radiation workers and other people, monitoring radiation zone and personal monitoring. According to International Atomic Energy Agency (IAEA) recommendation
there are definite programme in checking the radiotherapy machine every week, every month and every year. This is a part of quality assurance of radiotherapy.
Trained engineers and repairing systems of radiotherapy should be kept stand by. Any problem in the machine must be repaired promptly so that treatment remains uninterrupted.
Third step is the operation of the machines. Medical Technologists operate the machines.
Radiation oncologist, medical physicist and medical technologist jointly set up the first treatment and then tattoo the skin for the subsequent therapy. Besides this, the radiation oncologist checks up the patient thoroughly every week. The proper treatment depends on proper setting of the patients and properly operating the machines everyday.
Adverse effects
Every treatment has some side effects. Radiotherapy treatment has also side effects. Before starting treatment, the patient should be properly briefed, motivated and aware of all about the treatment. The treatment needs the support of trained nurses, social workers, family member and friends to help the patient cope with side effects and also motivational, mental, nutritional and other helps.
Appropriate treatment planning, expertise in setting the patient for treatment and proper functioning and operating of the machine will give the assurance of optimised radiotherapy.
The writer is Associate Professor, Department of Radiotherapy of Dhaka Medical College and Hospital.