Stereotactic Body Radiotherapy (SBRT)

Stereotactic Body Radiotherapy (SBRT) is a specialized form of radiation therapy that delivers precise doses of radiation to a small area within the body. SBRT usually involves a higher dose per treatment than conventional treatment. Also known as stereotactic ablative radiotherapy (SABR), SBRT is particularly effective for treating small, well-defined tumors. Its origins come from the technological advancement of stereotactic radiosurgery (SRS), which is a similar procedure, used specifically for brain tumors.

SBRT differs significantly from traditional radiation therapy in its precision and delivery. While conventional radiation therapy typically involves daily treatments over several weeks with lower doses per session, SBRT condenses the treatment into just a few sessions, often completed within one to five days. The higher doses of radiation in each session are precisely targeted using advanced imaging and treatment planning technologies, allowing for increased accuracy in hitting the tumor while sparing nearby healthy tissues. This approach not only enhances the therapeutic effect but also reduces the overall treatment duration, offering a more convenient and efficient option for certain patients.

Understanding SBRT

SBRT works by precisely delivering a highly concentrated dose of radiation to a specific target within the body. It relies on advanced imaging technologies, such as CT scans or MRI, to precisely locate and map the tumor in three-dimensional space. This detailed imaging information is then used to create a customized treatment plan. During treatment, the patient is positioned with great accuracy, often using immobilization devices, to ensure the targeted area receives the maximum dose while minimizing exposure to surrounding healthy tissues. The high doses of radiation are typically delivered in a small number of sessions, allowing for better control over the radiation’s impact on the tumor.

SBRT is commonly employed to treat various types of cancer in the body, such as:

  • Lung tumors
  • Liver tumors
  • Pancreatic cancer
  • Prostate cancer
  • Renal cell carcinoma
  • Certain types of spine and bone metastases

The suitability of SBRT depends on factors such as tumor size, location, and proximity to critical structures.

Benefits of SBRT

There are several advantages of SBRT over conventional cancer treatment methods like surgery or traditional radiation therapy. SBRT may be the right treatment method for you if you’re seeking any of the following:

  1. Precision and Targeting: SBRT allows for highly precise targeting of tumors, minimizing damage to surrounding healthy tissues. This precision is particularly advantageous for treating tumors near critical structures or organs.
  2. Shortened Treatment Duration: Compared to conventional radiation therapy which may span several weeks, SBRT typically delivers the entire course of treatment in a few sessions, offering greater convenience for patients and potentially reducing the overall treatment time.
  3. Effectiveness for Inoperable Tumors: SBRT can be an excellent option for patients with inoperable tumors or those who are not candidates for surgery. It provides a non-invasive alternative with a high likelihood of tumor control.
  4. Reduced Side Effects: Due to the focused nature of the treatment, SBRT often results in fewer side effects compared to traditional radiation therapy. The ability to spare healthy tissues contributes to a more favorable side effect profile.
  5. Improved Quality of Life: The shorter treatment duration and reduced side effects associated with SBRT can contribute to an improved quality of life for patients, allowing them to resume normal activities more quickly after treatment.
  6. Enhanced Patient Experience: The streamlined nature of SBRT, with fewer treatment sessions and reduced side effects, can enhance the overall experience for patients, potentially leading to better adherence to the prescribed treatment plan.

The SBRT Procedure

Your cancer care team will need to plan your stereotactic radiotherapy before administering treatment. This could include:

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Step One: Marking the Treatment Area

The team may place non-permanent marks on your skin that identify the treatment area.

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Step Two: Simulate the Treatment

You may be placed in an immobilization device that holds your body very still. Then you will undergo a CT simulation scan or “mapping session” in order to identify exactly where and how to deliver your treatment.

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Step Three: Plan Your Dosage

Using the information from the simulation, your radiation oncologist will determine the dose and delivery of your treatment.

The actual SBRT sessions involve the patient lying on a treatment table while a linear accelerator or other specialized equipment delivers highly focused radiation beams to the tumor. The patient is carefully positioned based on the treatment plan, and the radiation beams are administered from different angles to converge on the target.

After completing the SBRT sessions, patients are monitored for immediate side effects or complications. After completion of treatment, periodic imaging studies, such as CT scans or MRIs, are conducted to evaluate the tumor’s response to SBRT. This helps determine the effectiveness of the treatment and whether additional interventions are necessary.

Patients may experience mild side effects, such as fatigue or localized tissue reactions. These are typically temporary and can be managed with supportive care, including medications and lifestyle adjustments.

Regular follow-up appointments are scheduled to monitor the patient’s overall health, assess treatment response, and address any emerging concerns. Regular clinical assessments are used to monitor for any signs of recurrence or potential side effects. This includes discussions about their overall well-being and any changes in symptoms. These appointments may also include imaging studies to track changes in the tumor over time.

The post-treatment care and monitoring process in SBRT aims to ensure the patient’s well-being, assess treatment efficacy, and promptly address any emerging issues to optimize long-term outcomes.

Technology Used in SBRT

SBRT is an advanced, innovative technology that relies on a variety of imaging techniques and delivery systems for optimal, precise results.

Computed Tomography (CT) scans, Magnetic Resonance Imaging (MRI), and Positron Emission Tomography (PET) scans are commonly used to precisely visualize and locate tumors. These imaging modalities assist in creating a three-dimensional representation of the tumor, allowing for accurate treatment planning.

The actual doses of radiation may be delivered by a variety of systems, such as:

  • Linear Accelerators (LINAC): These machines generate and deliver high-energy X-ray beams that are precisely targeted at the tumor. Modern LINACs used in SBRT are equipped with advanced features such as image guidance and motion management to enhance accuracy during treatment.
  • CyberKnife and Gamma Knife: These are specialized radiosurgery systems that use robotic arms or a fixed array of gamma-ray sources to deliver highly precise radiation to the target. They are particularly effective for treating tumors in the brain and other delicate areas.
  • Volumetric Modulated Arc Therapy (VMAT) and Intensity-Modulated Radiation Therapy (IMRT): These techniques allow for the precise modulation of radiation dose intensity and delivery from multiple angles, conforming the radiation beams to the shape of the tumor. This enhances dose distribution accuracy and spares healthy tissues.

Throughout treatment, from planning to guidance during delivery, certain computer algorithms and technologies are used to certify that radiotherapy is occurring to the most efficient extent.

These algorithms analyze the patient’s imaging data and optimize the radiation delivery parameters, taking into account the size, shape, and location of the tumor, as well as the surrounding healthy tissues. Real-time imaging is also used during treatment, facilitated by these advanced image guidance systems.

The imaging systems use feedback from imaging devices to continuously verify and adjust the patient’s position, ensuring that the radiation is accurately delivered to the intended target. As patients may breathe or move during treatment, computer algorithms are employed to account for these motions. Techniques such as respiratory gating or tracking systems adjust the radiation delivery in real-time to accommodate movement, enhancing precision.

The integration of advanced imaging, precision radiation delivery systems, and sophisticated computer algorithms in SBRT collectively contributes to its ability to deliver highly accurate and targeted doses of radiation, minimizing damage to surrounding healthy tissues while maximizing the therapeutic impact on the tumor.

Potential Side Effects and Risks of SBRT

Like any cancer treatment, SBRT can have side effects, despite many of its associated benefits. Having an open conversation with your oncologist about the advantages and disadvantages of SBRT is the best way to decide if it’s right for you.

The short-term side effects of this treatment may include:

  • Fatigue
  • Tissue irritation
  • Nausea or Digestive Issues
  • Pain at the Treatment Site

Additionally, there are some long-term risks of radiotherapy. You may experience:

  1. Radiation Fibrosis: Long-term exposure to radiation may lead to the development of fibrosis, where normal tissues become less elastic and more prone to scarring. This can occur months to years after treatment.
  2. Radiation Pneumonitis: In cases of lung SBRT, there is a risk of radiation pneumonitis, an inflammation of the lung tissue. This can cause symptoms such as cough, shortness of breath, and fatigue. It is more commonly associated with higher doses of radiation.
  3. Late-Occurring Side Effects: While SBRT is designed to minimize damage to healthy tissues, there is a potential for late-occurring side effects, including secondary cancers, although the risk is generally low. The occurrence of these effects depends on factors such as the total radiation dose and the patient’s individual health.

You should always alert your doctor about the presence of side effects, in order to learn how to effectively manage them with medication or lifestyle adjustments. Certain methods may be used, such as:

  1. Medication: Symptomatic relief can often be achieved through medications. For example, pain relievers or anti-nausea drugs may be prescribed to manage specific side effects.
  2. Supportive Care: Supportive care measures, such as physical therapy or counseling, may be recommended to address specific side effects. These can help patients cope with symptoms and maintain their overall well-being.
  3. Close Monitoring: Regular follow-up appointments with healthcare providers allow for the close monitoring of side effects. Early detection and intervention can help manage any emerging issues and ensure that patients receive appropriate care.
  4. Lifestyle Adjustments: Patients may be advised to make lifestyle adjustments, such as maintaining a balanced diet, staying hydrated, and incorporating light exercise, to help mitigate side effects and promote overall health during and after SBRT.

Timely intervention and personalized management strategies as side effects appear are crucial to optimize the balance between treatment effectiveness and minimizing potential risks.

Conclusion

SERO stands out as one of the most experienced groups in the nation to provide this cutting-edge technology. With extensive experience and multiple locations for Charlotte cancer treatment, including Novant Presbyterian Hospital, Caromont Regional Medical Center, Rock Hill Radiation Therapy Center, and Frye Regional Medical Center, we successfully treat nearly 300 patients annually using SBRT.

Having been early adopters of this technology, our group of physicians has cultivated a distinctive expertise and wealth of experience. Many of our physicians have undergone specialized training in radiotherapy, positioning them as leaders in the field.

Beyond our team of seasoned radiation oncologists, SERO is committed to fostering a supportive and educational environment for all cancer patients. Whether you seek information about SBRT or desire a second opinion on your treatment options, we are dedicated to providing the assistance you need.

FAQs about SBRT

Is SBRT painful?

No. You will not feel the beams of radiation entering your body.

What is the difference between stereotactic radiosurgery (SRS) and SBRT?

While both terms refer to the same type of treatment, SRS is specific to brain tumors and SBRT is specific to those in the body.

How successful is SBRT radiation?

The success rates for SBRT depend upon a myriad of factors related to the situation (tumor type, stage, size, location, prior treatment, patient performance status, and more) but can range from 80 to 90 percent. Conventional treatment, in comparison, ranges from 30 to 40 percent.

What are the long-term side effects of SBRT?

Long-term side effects are not common but may include radiation fibrosis, where normal tissues become more prone to scarring, radiation pneumonitis in the case of thoracic lesions, or normal tissue irritation, depending on the target. Late-occurring side effects such as secondary cancers are very uncommon.

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