About Radiation Therapy
Radiation therapy, also known as radiotherapy, is a common treatment for cancer that uses high-energy radiation to kill cancer cells.
What is Radiation Therapy?
Radiation therapy, also known as radiotherapy, is a medical treatment that uses high doses of radiation to kill cancer cells and shrink tumors. This therapy works by damaging the DNA within cancer cells, which prevents them from growing and dividing. Over time, the damaged cancer cells die and are naturally eliminated by the body. Radiation therapy can be delivered externally or internally, depending on the type and location of the cancer.
External beam radiation therapy is the most common form of radiation therapy. It involves using a machine called a linear accelerator to direct high-energy beams of radiation at the cancerous area from outside the body. The machine can move around the patient to target the tumor from different angles, ensuring that the maximum dose of radiation is delivered to the cancer cells while minimizing exposure to surrounding healthy tissues.
Internal radiation therapy, or brachytherapy, involves placing a radioactive source directly inside or near the tumor. This method allows for a higher dose of radiation to be delivered to a more localized area, reducing the risk of damage to nearby healthy tissues. Brachytherapy is often used for cancers of the prostate, cervix, and breast.
Radiation therapy can be used at different stages of cancer treatment. It may be employed as the primary treatment to eradicate cancer, or it can be used before surgery (neoadjuvant therapy) to shrink tumors, making them easier to remove. After surgery, radiation therapy (adjuvant therapy) can help eliminate any remaining cancer cells. Additionally, it can be combined with other treatments, such as chemotherapy, to enhance the overall effectiveness.
Radiation therapy is a critical component of modern cancer treatment, with more than half of all cancer patients receiving it at some point during their treatment. Its ability to precisely target cancer cells while sparing healthy tissues makes it an invaluable option for many types of cancer.
Types of Radiation Therapy
Radiation therapy encompasses several different techniques used to treat cancer by targeting and destroying cancerous cells with high-energy radiation. The primary types include external beam radiation therapy (EBRT), where radiation is delivered from a machine outside the body, focusing beams on the tumor. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) are advanced forms of EBRT that allow for precise targeting of the tumor while sparing surrounding healthy tissue. Stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) involve delivering high doses of radiation in one or a few sessions with extreme accuracy, typically used for brain and small body tumors, respectively. Brachytherapy involves placing radioactive sources inside or near the tumor site, providing high radiation doses directly to the cancerous cells with minimal impact on nearby tissues. High dose rate (HDR) brachytherapy is a specific form of this treatment, delivering short bursts of radiation via temporarily placed sources. Lastly, intra-operative radiation therapy (IORT) delivers radiation during surgery, allowing for direct treatment of the tumor bed with high precision. Each type of radiation therapy is tailored to the specific cancer type, location, and patient needs, offering various strategies for effectively combating the disease.
Intensity modulated radiation therapy (IMRT)
Intensity-modulated radiation therapy (IMRT) is an advanced type of cancer treatment that uses computer-controlled linear accelerators to deliver precise radiation doses to a malignant tumor. By modulating the intensity of the radiation beams, IMRT allows for higher doses to be focused directly on the tumor while minimizing exposure to surrounding healthy tissues. This precision reduces the risk of side effects and increases the effectiveness of the treatment. IMRT is commonly used to treat various cancers, including prostate, head and neck, lung, brain, and gastrointestinal cancers. The treatment involves detailed planning using 3D imaging techniques, such as CT or MRI scans, to map the tumor and calculate the optimal radiation dose distribution. IMRT sessions are typically painless and last between 10 and 30 minutes, with the number of treatments varying based on the individual patient's needs.
Volumetric Arc Therapy (VMAT)
Volumetric modulated arc therapy (VMAT) is an advanced form of intensity-modulated radiation therapy (IMRT) used in the treatment of cancer. VMAT delivers precise radiation doses to a tumor by rotating the linear accelerator around the patient in a continuous arc, allowing for the modulation of radiation intensity and beam shape. This technique enables higher doses to be focused on the tumor while minimizing exposure to surrounding healthy tissues. VMAT's efficiency allows for shorter treatment times compared to traditional IMRT, reducing the time patients need to spend in the treatment position and improving overall patient comfort. The process involves detailed treatment planning using advanced imaging techniques like CT or MRI to accurately map the tumor and surrounding anatomy. VMAT is commonly used to treat various cancers, including those in the prostate, head and neck, brain, and gastrointestinal tract, offering precise and effective radiation therapy with reduced side effects.
Stereotactic radiation surgery & fractionated stereotactic therapy
Stereotactic radiation surgery (SRS) is a non-invasive form of radiation therapy that uses precisely focused radiation beams to target and treat tumors or abnormalities in the brain and other parts of the body. Unlike traditional surgery, SRS doesn't involve incisions; instead, it relies on advanced imaging techniques to deliver high doses of radiation with pinpoint accuracy, minimizing damage to surrounding healthy tissue. This method is often completed in a single session, making it a highly effective and efficient treatment option.
Fractionated stereotactic therapy (FST), on the other hand, involves delivering the radiation in multiple smaller doses over several sessions. This approach is used when treating larger tumors or when a more gradual treatment is needed to reduce potential side effects. By spreading the radiation over several sessions, FST allows healthy tissues to recover between treatments, while still effectively targeting the tumor.
Intra-operative radiation therapy
Intra-operative radiation therapy (IORT) is a specialized treatment that delivers a concentrated dose of radiation directly to a tumor site during surgery. This technique allows for the precise targeting of cancer cells while minimizing exposure to surrounding healthy tissues. IORT is often used in the treatment of cancers that are difficult to remove completely through surgery alone, such as certain breast, colorectal, and pancreatic cancers. During the procedure, the tumor is surgically exposed, and a radiation source is positioned to deliver a high dose of radiation to the tumor bed. This method can effectively kill remaining cancer cells and reduce the risk of recurrence. The targeted approach of IORT can also shorten the overall radiation therapy course, providing a significant advantage in terms of patient convenience and treatment efficacy. Post-operative care and monitoring are essential to ensure optimal healing and to manage any potential side effects.
High Dose rate brachytherapy
High dose rate (HDR) brachytherapy is a form of internal radiation therapy that delivers a high dose of radiation directly to the tumor site from within the body, using a temporarily placed radioactive source. Unlike external beam radiation therapy, which directs radiation from outside the body, HDR brachytherapy involves placing tiny radioactive pellets or seeds close to or inside the tumor through catheters or applicators. This precise targeting allows for higher doses of radiation to be concentrated in the tumor while minimizing exposure to surrounding healthy tissues. HDR brachytherapy is commonly used for treating cancers such as prostate, cervical, breast, and skin cancers. The procedure is typically performed on an outpatient basis and involves multiple short sessions, each lasting only a few minutes. This approach offers the advantage of shorter overall treatment times, reduced side effects, and the potential for better control of localized tumors. After the treatment, the radioactive source is removed, leaving no residual radioactivity in the body.
Why is Radiation Therapy done?
Radiation therapy is a crucial treatment modality in the fight against cancer, utilized for its ability to target and destroy cancer cells with precision. The primary goal of radiation therapy is to treat cancer by damaging the DNA within cancer cells, which prevents them from growing and dividing. This treatment can be used in various stages and for different purposes in cancer management.
One of the main reasons radiation therapy is employed is as a primary treatment to eradicate cancer. In some cases, it is the sole treatment used to cure cancer, especially for localized tumors that have not spread to other parts of the body. For instance, early-stage cancers of the head and neck, prostate, and cervix can often be effectively treated with radiation therapy alone.
Radiation therapy is also used before surgery (neoadjuvant therapy) to shrink tumors, making them easier to remove surgically. This approach can increase the likelihood of a successful surgery and reduce the risk of cancer recurrence. Conversely, after surgery (adjuvant therapy), radiation therapy can help eliminate any remaining cancer cells that were not removed during the operation, thereby reducing the risk of the cancer coming back.
In addition to its curative potential, radiation therapy plays a significant role in palliative care. For patients with advanced cancer, where a cure is not possible, radiation therapy can be used to relieve symptoms and improve quality of life. It can help shrink tumors that are causing pain, pressure, or other symptoms, such as difficulty breathing or swallowing.
Radiation therapy is often combined with other treatments, such as chemotherapy, to enhance its effectiveness. This combination can be particularly beneficial in treating certain types of cancer, such as head and neck cancers, where the synergy between radiation and chemotherapy can lead to better outcomes.
Moreover, radiation therapy is not limited to cancer treatment. It can also be used to treat non-cancerous conditions, such as benign tumors and certain neurological disorders. For example, it can be used to shrink benign brain tumors or to treat trigeminal neuralgia, a chronic pain condition affecting the facial nerves.