How Radiation Therapy Is Used to Treat Cancer

How Radiation Therapy Is Used to Treat Cancer

Radiation therapy, also known as radiation treatment, radiotherapy, irradiation, or x-ray therapy, is a widely utilized approach in cancer treatment. This method harnesses the power of high-energy particles or waves, such as x-rays, gamma rays, electron beams, or protons, to either destroy or impair cancer cells.


What is radiation therapy?

In the natural course, cells undergo growth and division to generate new cells. However, cancer cells exhibit a faster growth and division rate than most normal cells. Radiation therapy functions by inducing small breaks in the DNA within cells. These breaks impede the growth and division of cancer cells, ultimately leading to their demise. It is noteworthy that nearby normal cells may also be impacted by radiation, but the majority typically recover and resume their normal functions.

In contrast to chemotherapy and other treatments administered orally or through injection, which often expose the entire body to cancer-fighting drugs, radiation therapy is predominantly a localized treatment. It is directed specifically at the part of the body requiring intervention. Careful planning ensures that radiation treatments aim to damage cancer cells with minimal impact on surrounding healthy cells.

Some radiation treatments, known as systemic radiation therapy, involve the use of radioactive substances administered intravenously or orally. Despite the distribution of this type of radiation throughout the body, the radioactive substance tends to accumulate predominantly in the tumor area. Consequently, the impact on the rest of the body is limited.

Who gets radiation therapy?

Radiation therapy is administered to over half of individuals diagnosed with cancer. Its application varies, with instances where radiation therapy stands as the sole treatment for cancer, while in other cases, it is combined with alternative forms of treatment. The decision to incorporate radiation therapy into a treatment plan is contingent upon factors such as the specific type and stage of cancer, as well as any additional health considerations the patient may have.

What are the goals of radiation therapy?

Radiation therapy, while not universally effective for cancers that have extensively spread throughout the body, remains a versatile treatment option either as a standalone approach or in conjunction with other therapies. Each cancer case and patient's unique circumstances must be considered, but radiation therapy is often the preferred choice for the following purposes:

Cure or Shrinkage of Early-Stage Cancer:

Radiation therapy is particularly potent against cancers that exhibit high sensitivity to radiation. In some cases, it may be employed as the sole treatment, leading to the reduction or complete eradication of the cancer. For certain cancers, radiation may precede surgery to shrink tumors (known as pre-operative or neoadjuvant therapy) or follow surgery to prevent cancer recurrence (adjuvant therapy).

Preferred Treatment for Curable Cancers:

In cases where cancer can be cured either through radiation or surgery, radiation may be the preferred option. This choice is often made to minimize damage and ensure optimal functioning of the treated body part post-treatment.

Combined Therapy with Chemotherapy:

Radiation and chemotherapy, or other anti-cancer drugs, may be administered simultaneously for certain cancer types. Radiosensitizers, a category of drugs, can enhance radiation's effectiveness by increasing cancer cell sensitivity. Although this combined approach can yield better results, it may also intensify side effects.

Prevention of Cancer Recurrence Elsewhere:

Cancer has the potential to spread to other body parts, even when not visible on imaging scans. Radiation therapy is strategically employed to target areas prone to cancer spread, preventing the growth of cancer cells before they form tumors. For instance, individuals with specific lung cancers may receive radiation to the head as a preventive measure, particularly if their cancer type often metastasizes to the brain.

Palliative Radiation for Advanced Cancer:

In cases where cancer has advanced beyond a curative stage, radiation therapy can still play a crucial role in reducing tumor size to alleviate symptoms. Symptoms like pain, difficulty swallowing or breathing, and bowel blockages can be addressed through palliative radiation.

Treatment for Recurrent Cancer:

In situations where cancer returns, radiation therapy may be employed either to treat the cancer directly or to manage symptoms caused by the recurrent cancer. Factors influencing the decision include the location of recurrence, prior radiation treatments, and the responsiveness of the tumor to radiation. It's important to note that the effectiveness of radiation therapy can vary based on individual circumstances, and decisions are made collaboratively between patients and their healthcare teams.

How is Radiation Therapy Administered?

Radiation therapy is delivered through three primary methods:

External Radiation (External Beam Radiation):

Utilizes a machine that directs high-energy rays from outside the body into the tumor. Typically conducted during outpatient visits to a hospital or treatment center. Administered over several weeks, with some cases requiring twice-daily sessions for weeks. Individuals receiving external radiation are not radioactive and do not need special safety precautions at home.

Internal Radiation (Brachytherapy):

Also known as brachytherapy, this method involves placing a radioactive source inside or near the tumor. In certain brachytherapy types, radiation remains inside the body to exert its effect. Alternatively, it may be inserted for a specific duration and then removed, a decision influenced by the cancer type. Special safety precautions are necessary during the period of internal radiation. However, it's crucial to note that if the radioactive material is left in the body, it eventually becomes non-radioactive.

Systemic Radiation:

Involves the use of radioactive drugs administered orally or intravenously to treat specific cancer types. These drugs circulate throughout the entire body. Special precautions may be required at home for a designated period following the administration of these drugs. The choice of radiation delivery method depends on the type and location of the cancer. In certain situations, a combination of these methods may be employed. The healthcare team managing your cancer care can provide detailed information about the specific radiation type prescribed for your treatment, its impact on your body, and any necessary precautions.

Who Administers Radiation Therapy Treatments?

Throughout your radiation therapy, a dedicated team of highly skilled medical professionals will be responsible for your care. Your team may consist of:

Radiation Oncologist:

This specialized doctor is trained in utilizing radiation to treat cancer and oversees your entire radiation treatment plan.

Radiation Physicist:

Responsible for ensuring the proper functioning of the radiation equipment, the radiation physicist ensures that you receive the precise dose prescribed by your radiation oncologist.


Collaborating with the radiation oncologist, the dosimetrist assists in planning the treatment, ensuring accuracy and efficacy.

Radiation Therapist or Radiation Therapy Technologist:

Operating the radiation equipment, this professional positions you for each treatment session, ensuring precise delivery of radiation.

Radiation Therapy Nurse:

Specially trained in cancer treatment, the radiation therapy nurse provides information about radiation treatment and assists in managing potential side effects. Additional healthcare providers may also play a role in your care, including but not limited to:

Dietitian: Offers nutritional guidance tailored to your needs during treatment. Physical Therapist: Assists in maintaining or improving physical function during and after treatment. Social Worker: Provides support and resources to address emotional and practical concerns. Dentist or Dental Oncologist: Manages oral health concerns, especially important during head and neck radiation. Pharmacist: Ensures appropriate medications and manages potential drug interactions. Other Health Care Providers: Depending on your specific needs, various healthcare professionals may contribute to your comprehensive care.

This collaborative and multidisciplinary approach ensures that you receive comprehensive support and expertise throughout your radiation therapy journey.

Can Radiation Therapy Cause Cancer?

It is established that radiation therapy carries a slight increase in the risk of developing another cancer. This potential side effect is a crucial consideration for doctors when evaluating the benefits and risks of each treatment. While the risk of developing a second cancer due to radiation therapy is generally small and often outweighed by the benefits of treating the primary cancer, it is not entirely negligible. This variability underscores the importance of tailoring treatments to individual cases, with patients actively participating in the decision-making process regarding their preferred treatment.

The level of risk is influenced by the location of the radiation treatment within the body. Despite the potential risk, if your cancer care team recommends radiation treatment, it is because they believe the benefits outweigh the possible side effects. Ultimately, the decision rests with you. Gaining a comprehensive understanding of the potential advantages and risks empowers you to make an informed choice regarding the suitability of radiation therapy for your specific circumstances.

Impact of Radiation Therapy on Pregnancy and Fertility:

For Females:

It is crucial to avoid pregnancy during radiation therapy, as it can pose risks to the developing baby. If there's a possibility of pregnancy, discuss suitable birth control options with your doctor. If you are already pregnant or might be, inform your doctor promptly.

When the radiation field includes the ovaries, there is a potential risk of rendering them nonfunctional (sterility), making it difficult to conceive. It's essential to be aware of this risk before undergoing radiation therapy. If your treatment plan involves areas affecting the ovaries, consult with your doctor to understand how it may impact your fertility and future family planning.

For Males:

The impact of radiation therapy on offspring conceived by men during treatment is not extensively studied. Consequently, men are often advised to avoid impregnating a woman during and for several weeks after completing treatment. Discuss this aspect with your doctor for more personalized information.

If the testicles are within the radiation field, there is a potential risk of rendering them nonfunctional (sterility), impacting fertility. Understanding this risk beforehand is crucial. Limited research exists on how radiation-exposed sperm affects future offspring. If contemplating radiation therapy affecting the testicles, consult your doctor to assess how it may influence your ability to have children in the future.