Radiation Therapy

Radiation therapy, also known as radiotherapy, is a type of cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. It is one of the most common treatments for cancer, used in more than half of all cancer cases.

The therapy can be utilized alone or in conjunction with other treatments, such as surgery, chemotherapy, and immunotherapy, depending on the type, location, and stage of the cancer.

Types of Radiation Therapy

There are two main types of radiation therapy: external beam radiation therapy (EBRT) and internal radiation therapy (brachytherapy).

1. External Beam Radiation Therapy (EBRT):

  • In EBRT, beams of radiation are directed from outside the body onto the cancerous area.
  • It involves the use of sophisticated machines, such as linear accelerators, which can adjust the radiation dose and shape to the contours of the tumor, minimizing damage to surrounding healthy tissue.
  • Techniques include intensity-modulated radiation therapy (IMRT), stereotactic radiosurgery (SRS), and proton beam therapy, each offering distinct advantages and used based on the tumor’s characteristics.

2. Internal Radiation Therapy (Brachytherapy):

  • Brachytherapy involves placing a radiation source inside or next to the area requiring treatment.
  • Commonly used for cancers of the cervix, prostate, breast, and skin, brachytherapy allows for a high radiation dose to be applied to a smaller area over a shorter time compared to EBRT.
  • The radiation sources can be temporary or permanent, depending on the type and stage of cancer.

How Radiation Therapy Works

Radiation therapy works by damaging the DNA of cancer cells, thereby inhibiting their ability to reproduce and grow. While it can also damage normal cells, they are generally more resilient and can repair themselves more effectively than cancer cells.

Treatment Planning

Radiation therapy is meticulously planned using imaging tests like CT, MRI, and PET scans to determine the exact shape and location of the tumor. This planning ensures that the maximum radiation dose is delivered to the cancer cells while sparing the surrounding healthy tissue as much as possible.

Side Effects

The side effects of radiation therapy vary depending on the treatment area and can include fatigue, skin changes, and other organ-specific issues. For example, radiation to the abdomen can cause gastrointestinal symptoms, while treatment to the head and neck area might result in dry mouth or difficulty swallowing. Most side effects are temporary, but some may persist or emerge long after treatment has concluded.


Radiation therapy remains a cornerstone of cancer treatment, offering hope and improved outcomes for many patients. Advances in technology and technique continue to enhance its effectiveness and reduce side effects, making it a vital tool in the fight against cancer.

Patients undergoing radiation therapy should have a thorough discussion with their oncology team to understand the specific goals, potential benefits, and risks associated with their treatment plan.