From the Guidelines
Radiation therapy techniques like IMRT, VMAT, stereotactic radiotherapy, and brachytherapy offer targeted cancer treatment options with varying degrees of precision and application, with the most recent evidence from 1 highlighting their effectiveness in reducing morbidity and mortality.
Overview of Radiation Therapy Techniques
- Intensity-Modulated Radiation Therapy (IMRT) uses multiple radiation beams of varying intensities to conform to tumor shape, allowing high doses to the tumor while sparing surrounding healthy tissue, as noted in 1.
- Volumetric Modulated Arc Therapy (VMAT) is an advanced form of IMRT where the machine rotates around the patient while continuously delivering radiation, resulting in faster treatment times while maintaining similar precision, as described in 1.
- Stereotactic radiotherapy delivers extremely precise, high-dose radiation to small, well-defined targets using multiple beams from different angles, often completed in 1-5 sessions rather than weeks of conventional treatment, with evidence from 1 supporting its use in brain metastases.
- Brachytherapy involves placing radioactive sources directly into or adjacent to tumor tissue, delivering high doses locally while minimizing exposure to surrounding tissues, and is commonly used for prostate, cervical, and breast cancers, as discussed in 1.
Key Considerations
- The selection of radiation therapy technique depends on tumor location, size, and patient factors, with radiation oncologists determining the best approach for individual clinical scenarios, as emphasized in 1.
- Recent studies, such as 1, have demonstrated the effectiveness of stereotactic radiation therapy in treating brain metastases, with high local control rates and improved cognitive outcomes.
- Brachytherapy is a critical component of therapy for cervical cancer, with evidence from 1 supporting its use in combination with external-beam radiation, and 1 highlighting the importance of precise treatment planning and delivery.
Recommendations
Based on the most recent evidence from 1 and 1, stereotactic radiotherapy is recommended for small tumors in the brain, lung, liver, and spine, while brachytherapy is recommended for prostate, cervical, and breast cancers, with IMRT and VMAT used for irregularly shaped tumors near critical structures.
From the Research
Overview of Radiation Therapy Techniques
- Intensity-modulated radiation therapy (IMRT) is a technique that delivers radiation more precisely to the tumor while sparing surrounding normal tissues 2, 3.
- Volumetric-modulated arc therapy (VMAT) is a type of IMRT that uses a rotating gantry to deliver radiation in a single optimized arc around the patient 2, 4.
- Stereotactic radiotherapy, including stereotactic body radiation therapy (SBRT), is a technique that delivers high doses of radiation to small, well-defined tumors in a few fractions 5.
- Brachytherapy is a technique that involves placing a radioactive source directly into or near the tumor to deliver radiation 5.
Comparison of Radiation Therapy Techniques
- IMRT and VMAT can produce dose distributions of similar quality, but VMAT can significantly reduce treatment time and monitor units required to deliver a patient's treatment 2, 4.
- SBRT and IMRT have been compared to brachytherapy in the treatment of invasive cervical cancer, with SBRT showing comparable overall survival to brachytherapy, but IMRT showing a significant overall survival detriment 5.
- Hybrid IMRT/VMAT techniques have been investigated for the treatment of nonsmall cell lung cancer, showing improved target conformity and homogeneity compared to IMRT and VMAT alone 4.
Considerations for Radiation Therapy Techniques
- The choice of radiation therapy technique depends on considerations such as the availability of the specific treatment type, its impact on departmental planning and treatment resources, and the individual patient's needs 2, 6.
- Quality assurance (QA) procedures are essential to ensure the safe and reliable delivery of radiation therapy, including IMRT and VMAT 6.