How External Beam Radiation Therapies Treat Cancer

Medically reviewed by Dr Johann Tang, Senior Consultant Radiation Oncologist

External Beam Radiation Therapy (EBRT) is a cancer treatment modality that utilises external radiation to kill cancer cells. Treatment Machines called the Linear Accelerator (LINAC) focus precise high-energy beams at cancerous tumours, damaging their DNA while limiting the harm to the healthy tissue adjacent to it.

This kind of radiation therapy in Singapore is used to treat many different types of cancer. Before EBRT is prescribed, the type of cancer, the size of the tumour, the location in the body, and the patient’s general condition and medical history must all be taken into account.

With this information on hand, a Radiation Oncologist is then able to recommend the exact type of EBRT therapy. Different types of EBRT, such as Intensity-Modulated Radiation Therapy (IMRT), Stereotactic Body Radiation Therapy (SBRT) and Proton Beam Therapy (PBT) all have their use in specific situations. The final radiation therapy chosen will take all factors into account.

Of the three, Proton Beam Therapy (PBT), is different in that it doesn’t use high energy X-rays to kill cancer cells. Instead, it utilises targeted proton beams to deliver precise radiation doses to the tumor cells only, thereby reducing radiation to surrounding healthy tissues and decreasing incidence of side-effects. Read on to find out more about how PBT works and why it is an effective tool in the arsenal to cure cancer.

Proton Beam Therapy (PBT)

While most radiation treatments rely on X-ray radiation, Proton Beam Therapy (PBT) uses high energy protons to destroy cancer cells. 

This provides a significant advantage over conventional treatments as X-rays continue to emit radiation doses as they leave the body. With proton therapy, because of the proton physical characteristics known as the Bragg Peak, there is less radiation dosage outside the tumour itself. This potentially reduces side-effects for patients who are prescribed proton beam therapy over conventional EBRT treatments.

The precision of proton therapy comes from Pencil Beam Scanning, which targets tumours with a narrow proton beam only a few millimetres wide. Tailored to the individual tumour size and shape, the intensity is carefully modulated to deliver accurate doses to the cancer.

One main benefit of proton beam therapy is that it can target tumours too close to challenging areas in the body for other radiation therapy treatments to be as effective. Proton Beam Therapy is most useful for treating tumours that have not spread and are located close to vital organs in the body such as the brain and spinal cord, head and neck tumors and prostate cancer. Children are also ideal candidates as it reduces the chances of damaging healthy growing tissue, which is essential for normal growth.

Proton therapy generally takes place over a number of weeks with each session lasting about a half hour. While the total number of sessions is largely dependent on the size of the tumour and the type of cancer you have, in some cases, the treatment can be completed in about 5 to 30 sessions depending on the cancer type.

Due to the decreased radiation delivery to surrounding healthy tissue, high doses of radiation can be targeted at the cancer itself. This increases the chances of killing all the targeted tumour cells and improving the patient’s condition. However, Proton Beam Therapy requires highly specialised and costly equipment and may not be a viable treatment option for some types of cancers. Please consult your doctor to determine if your cancer is suitable for Proton Beam Therapy

External Beam Radiation Therapy is a well-established treatment modality for many different types of cancers. It is a highly advanced effective treatment modality.

With numerous ongoing clinical studies on the effectiveness of various types of EBRT treatments and proton therapy in Singapore, it’s important to be well-informed and talk to a trusted and highly-experienced Radiation Oncologist and consult on your various treatment options.

Contact us today to book an appointment with Dr Johann Tang for any queries relating to radiation therapy treatment in Singapore.