The Principles, Techniques, and Applications of Radiotherapy in Cancer Management

Radiotherapy, or radiation therapy, is a versatile and indispensable modality in modern cancer management. It is a non-invasive treatment approach that uses high-energy ionising radiation to destroy cancer cells and shrink tumours. Radiotherapy has demonstrated significant benefits in cancer treatment, including improved survival rates, better local control, and enhanced quality of life for patients. This essay delves into radiotherapy’s principles, techniques, and applications in cancer management.

Radiotherapy works on the principle that ionising radiation damages the DNA of cancer cells, leading to cell death or impaired cell division. Ionising radiation generates reactive molecules such as free radicals, which can break chemical bonds in DNA, causing strand breaks, cross-linking, or other forms of damage. Cancer cells are more susceptible to the effects of radiation than normal cells because they divide more rapidly and have impaired DNA repair mechanisms.

There are two primary forms of radiotherapy: external beam radiotherapy (EBRT) and internal radiotherapy (brachytherapy).

• External Beam Radiotherapy (EBRT) is the most common form of radiotherapy, where a machine called a linear accelerator directs high-energy X-rays or electrons at the tumour site. The radiation is carefully shaped to match the size and shape of the tumour, minimising damage to surrounding healthy tissue. Intensity-radiation treatment (IMRT) and volumetric-modulated arc therapy (VMAT) are advanced forms of EBRT that allow for even more precise targeting of tumours.
• Brachytherapy involves placing radioactive material directly into or near the tumour. The radioactive material, often in the form of seeds, pellets, or wires, emits radiation that destroys the nearby cancer cells. Brachytherapy is commonly used to treat prostate, cervix, head and neck cancers.

Radiation therapy has various applications in cancer treatment, either as a standalone therapy or combined with other modalities such as surgery or chemotherapy. Some of the key applications include:

• Radiotherapy can destroy cancer cells and achieve a complete cure, especially in early-stage cancers where the tumour is localised and has not spread to other parts of the body.
• Adjuvant treatment can be used after surgery to kill any remaining cancer cells or reduce the recurrence risk. For example, breast cancer patients may receive radiotherapy following a lumpectomy or mastectomy.
• Neoadjuvant treatment can be used before surgery to shrink a tumour, making removing and reducing the risk of complications easier.
• Palliative treatment is used where a cure is impossible; radiotherapy can help alleviate symptoms and improve quality of life by shrinking tumours causing pain, bleeding, or obstruction.