Radiation Treatment of Cancer Dr. Rajesh Pasricha. Consultant Radiation Oncologist Bhagwan Mahaveer Cancer Hospital & Research Centre. Jaipur
Radiotherapy is a crucial pillar in the treatment of cancer. This medical specialty of cancer treatment uses calibrated dose of radiation to treat cancer. Around 80% of all the cancers require radiation therapy somewhere during the treatment.
What is radiotherapy Radiotherapy is a form of treatment that uses precisely targeted high-energy rays (including X-rays) to kill cancer cells. The aim of radiotherapy is to cure cancer, wherever possible, whilst maintaining acceptable function and cosmesis (appearance of body). Radiotherapy can be used alone or with chemotherapy or surgery.
How radiotherapy acts It acts by damaging DNA an internal component of cell, this damage causes cell death by a process called apoptosis. This stops and sometimes limits the growth of fast dividing cancer cells. The radiation damages both normal and cancer cells. Normal cells are able to repair the effects of radiotherapy better than malignant and other abnormal cells. This leads to control of tumor growth with minimal damage to surrounding normal organs of body
What are the types of radiotherapyExternal beam radiation is the most common form. This method carefully aims high powered x-rays directly at the tumors from outside of the body. This process is carried out by Linear Accelerator or older  process by Telecobalt  machines.
 
Internal radiation uses radioactive seeds (Source) which is placed directly into or near the tumor. Internal beam radiation is also called Brachytherapy. Who gets radiotherapy The principal use of radiotherapy is to tackle solid tumors found in just one location, for example skin, brain, breast or uterine cancers. Sometimes it is used (alone or in combination with chemotherapy) to shrink a tumour so that a subsequent surgery will be more effective e.g in rectum cancer.In some cases Radiotherapy is considered as the first option, as an alternative to surgery that would have permanent effects on thelifestyle of the patient for example in cancer of larynx (voice box). Treatment with radiation in these cancers can save the organ and at the same time cure the cancer  In some cases the radiotherapy is given after surgery to "mop up" any remaining cancer cells which have spread from the original cancer site into the surrounding area. It is also used in patient with incurable and advanced stage of Cancer where Radiotherapy is used to control symptoms like pain and bleeding (Palliative radiotherapy), What about side-effectsAlthough the treatment itself is painless at the time, the cumulative effect of many sessions does produce side effects. The side effects of radiotherapy can be broadly split into two categories, the early or acute side effects and late side effects. The early side effectsThese come on during or shortly after treatment. These include sunburn-like effect (redness and itching) on the skin. There can be hair loss in the area being treated - which is usually temporary. The treatment can also leave the patient feeling fatigued and lethargic. Specific side-effects associated witssh radiotherapy administered to specific parts of the body for instance radiotherapy in the abdomen can lead to nausea and vomiting.The Late side effects
Late side effects are those which can develop months or even years after the end of radiotherapy. The type of side effect again depends upon which area was irradiated. For example, during treatment of mouth and throat cancers treatment if salivary glands are irradiated, patient might get dryness of the mouth which can last several months after treatment and may be permanent. Other late side effects are rare, seen in less the 4-5% of all the treated cases. These include:-•    Thickening of the skin and underlying structures  •    Damage to the ractum. •    Damage to the heart and lungs. •    Even rarer, in 1- 2% of persons, a secondary malignancy may be induced 15-20 years after primary treatment.