What are the key considerations for developing effective radiation oncology plans?

Key Considerations for Developing Effective Radiation Oncology Plans

Multidisciplinary Team Approach

Radiation therapy planning requires mandatory collaboration between radiation oncologists, nuclear medicine physicians, radiologists, medical oncologists, surgeons, medical physicists, and specialized technologists to optimize treatment outcomes. 1

• Radiation oncologists must evaluate mammography findings, pathology results, and surgical procedures performed before initiating treatment planning. 1
• Nuclear medicine physicians and radiologists should be readily accessible during target delineation, particularly when interpreting PET/CT findings or addressing questions about physiologic uptake versus pathologic findings. 1
• Medical physicists with nuclear medicine expertise must perform quality control of imaging equipment and ensure adherence to international dosimetry standards. 1
• Close cooperation between radiation oncologists and medical oncologists is essential for integrating radiation therapy with chemotherapy regimens. 1

Facility and Equipment Standards

Treatment facilities must conform to American College of Radiology standards for radiation oncology facilities. 1

• Supervoltage equipment must be selected to ensure dose homogeneity throughout the treatment volume. 1
• High-energy photons (≥10 MV) should be used for large-breasted women or patients with significant dose inhomogeneity when using lower energy photons. 1
• Quality control procedures must be implemented by dedicated medical physicists before final treatment plan approval. 1

Treatment Timing and Patient Preparation

Radiation therapy should begin within 2 to 4 weeks after uncomplicated surgery, as soon as adequate healing has occurred. 1

• Optimal patient preparation for PET/CT imaging includes achieving proper 2-[18F]FDG biodistribution and ensuring stable, reproducible positioning. 1
• Respiratory gating should be validated and implemented when available for thoracic treatments. 1
• Isocentre reference points must be marked on the patient by trained technologists. 1

Target Volume Delineation Process

Target volume definition and delineation must be performed or supervised by radiation oncologists, with peer review by another radiation oncologist highly recommended due to significant inter-observer variation. 1

• Departmental instructions for gross tumor volume (GTV) delineation should be developed, including reproducibility testing within the nuclear medicine department. 1
• Hybrid image co-registration must be consistently verified before any target delineation begins. 1
• The delineation process should account for the extent, nature, and location of the tumor, as well as patient breast size and concerns about local recurrence versus cosmetic appearance. 1

Treatment Planning Technical Requirements

Measures to ensure reproducibility must be implemented for patient set-up, treatment simulation, treatment planning, and supervoltage equipment selection. 1

• Three-dimensional dose distributions accounting for lower lung tissue density may be used, though their impact on patient outcomes has not been demonstrated and they are not considered standard. 1
• Treatment planning is an iterative process involving medical physicists, dosimetrists, and radiation oncologists, requiring anywhere from one hour to one week depending on complexity. 2
• Physical radiation therapy planning and dose calculations must be reviewed by a dedicated physicist before final approval. 1

Standard Dosing and Fractionation

Whole breast radiation therapy should be delivered using opposed tangential fields to a dose of 4,500 to 5,000 cGy at 180 to 200 cGy per fraction. 1, 3

• Each field should be treated daily, Monday through Friday. 1
• Bolus should not be used during treatment as it increases skin reactions. 1, 3
• Boost irradiation to the primary tumor site increases the total dose to approximately 6,000 to 6,600 cGy using electron beam or interstitial implantation. 1

Organ at Risk Protection

To minimize radiation pneumonitis risk, no more than 3.0 to 3.5 cm of lung (as projected on the beam radiograph at isocenter) should ordinarily be treated, with a minimum of 1.0 to 1.5 cm required. 1

• For left-sided lesions, efforts must be made to minimize the amount of heart included in tangential fields. 1
• The objective is to ensure precise irradiation of the target volume while sparing organs at risk as much as possible. 2

Quality Assurance and Safety

Image-guided radiation therapy is standard practice for patient alignment during treatment delivery. 2

• Skin reactions should be assessed at least once weekly during treatment. 3
• Radiation dose monitoring must be performed by medical physicists to minimize exposure while ensuring diagnostic or therapeutic success. 1
• The ALARA (As Low As Reasonably Achievable) principle should guide all protocol considerations. 1

Documentation and Follow-up

The radiation oncologist must manage acute toxicities during treatment and prepare a comprehensive summary upon completion. 2

• A written request for imaging studies should contain all standard information including location of primary tumor, previous radiation therapy dates/doses/locations, and concurrent chemotherapy regimens. 1
• Patient selection should be carefully documented, avoiding inappropriate testing and procedures through use of appropriate use criteria. 1