Radiation therapy is a crucial component of cancer treatment, employed to either eliminate cancer cells or inhibit their growth by damaging their DNA. This process is a meticulous one, requiring time for the radiation to work its effects. Here, we explore the mechanism of radiation therapy, its different types, and its role in cancer care.

At high doses, radiation therapy targets and damages the DNA within cancer cells. When this DNA damage becomes irreparable, the cancer cells cease to divide or perish. The body's natural processes then eliminate these damaged cells, gradually reducing the cancer's presence. This explains why radiation therapy doesn't produce immediate results, often requiring days or weeks of treatment before the full impact is seen. Moreover, the effects continue for weeks or months even after radiation therapy concludes.

There are two primary types of radiation therapy: EBRT & BRACHYTHERAPY.

External Beam Radiation Therapy

This type of radiation therapy employs a machine that directs radiation at the cancer site. The machine, though large and potentially not noisy, doesn't touch the patient but orbits around them, delivering radiation from multiple angles. External beam radiation is localized, meaning it specifically targets the affected area, minimizing damage to surrounding healthy tissues. For example, if a patient has lung cancer, radiation will be focused solely on the chest.

Brachytherapy

In this approach, radiation sources like seeds, ribbons, or capsules are positioned in or near the tumour. Similar to external beam radiation, brachytherapy is a localized treatment, concentrating on a specific area of the body. The radiation source within the body emits radiation over time.

Systemic Therapy

Systemic radiation therapy utilizes a liquid radiation source. It travels through the bloodstream, seeking out and destroying cancer cells throughout the body. Administration can occur through ingestion, IV infusion, or injection. Afterward, bodily fluids, such as urine, sweat, and saliva, may emit radiation temporarily.

Radiation therapy serves two main purposes in cancer care:

• Curative: Radiation therapy can potentially cure cancer, prevent its recurrence, or slow down its growth.

• Palliative: In some cases, radiation therapy is used to alleviate cancer symptoms. For instance, external beam radiation can shrink tumours, easing pain and other complications caused by the tumor, such as breathing difficulties or loss of bladder control. Systemic radiation therapy drugs, known as radiopharmaceuticals, can address bone pain resulting from cancer that has spread to the bones.

While radiation therapy may be the sole treatment for some individuals, it's often part of a comprehensive approach that includes surgery, chemotherapy, and immunotherapy. The timing of radiation therapy depends on the type of cancer and its intended goal, whether that's targeting the cancer itself or alleviating symptoms:

• Before Surgery: Radiation therapy can be administered before surgery to shrink the tumor's size, making it easier to remove and reducing the likelihood of recurrence.

• During Surgery: In some cases, radiation therapy can be applied directly to the cancer during surgery, a technique known as intraoperative radiation.

• After Surgery: Post-surgery, radiation therapy may be used to eradicate any remaining cancer cells.

It's essential to note that radiation therapy, while effective against cancer, can affect neighbouring healthy cells, potentially causing side effects.