Reproduction at astoundingly high rates of cells leads to the formation of tumors. Radiation therapy is designed to check the high reproduction of such cells. High energy X-Rays are released which cause damage to the DNA structure of such cells, hence causing a break in their reproduction abilities.

It also causes some amount of damage to normal cells, but since they don’t reproduce as fast anyway, the damage is minimal. The radiation regimen is usually kept at large intervals and very low doses to give time to normal cells to heal. Surveys have revealed that almost a half of the patients diseased with cancer receive some form of radiation during the course of their treatment.

Since it acts at localized regions, radiation therapy is called a local therapy. Two forms of radiation exist, external – where beams are directed from outside of the human body, and internal – where the source of the radiation is placed near the tumor inside the body, also called brachytherapy or implant therapy.

External radiation therapy is also known as cobalt therapy, X-ray therapy, proton therapy or IMRT (Intensity Modulated Radiation Therapy). Patients are usually given a weekend gap to give time to their cells to heal. This reduces side-effects. In internal therapy, source of the radiation is kept as close to the cancer cells as possible.

This allows doctors to give highly concentrated doses of radiation in a much shorter time as compared to external radiation. The radioactive substances used typically are cesium, radium, phosphorous, iodine, etc. Depending on this material used, patients with internal radiation will need to be separated from other people. This avoids exposure to radiological activity for others.

The radiation doses also hurt healthy cells. For this reason, radiation applied on the abdomen can cause diarrhea due to damage to healthy cells of the bowels. Most of these side-effects are temporary, however, so this is merely a temporary inconvenience.

Practitioners need to see the cancer patients at least once a week to check their treatment progress and also to check their side effects. This visit to a hospital can stimulate patients to ask questions or clear any queries they might have regarding their treatment and side effects.

The side effects due to radiation therapy depend on the individual patient and also on the specific area being treated. These may include some damage causing the treatment regimen to be disrupted.

Some of these side-effects include:

(i) Hair loss: This happens if the radiation is directed somewhere close to the scalp. The hair may re-grow depending on the total radiation dose delivered.

(ii) Fatigue: This is one of the more common side-effects. Patients usually tend to work even when undergoing treatment. This, coupled with the loss of cell mass while undergoing radiation can call a decrease in the neurophil numbers, causing a condition known as neutropenia. This puts the patient at high infection risk.

(iii) Long-term complications

Based on the type of cancer being treated, you may need to have continuous periodic radiation studies which help estimate the change in status of the tumor. This can be done through the blood using a tumor marker.