[Normal tissue tolerance to external beam radiation therapy: Bone marrow and cortical bone structures]

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy

Background:

• Bone marrow and cortical bone are frequently neglected as organs at risk during external radiation therapy.
• Adverse effects, including febrile neutropenia and vertebral fractures, are common and can be severe.
• These risks are associated with various radiotherapy techniques, from chemoradiation for pelvic tumors to stereotactic radiotherapy for spinal metastases.

Purpose of the Study:

• To define contouring rules for bone marrow and cortical bone structures.
• To present currently recommended dose constraints for these organs.
• To review recommendations for both conventional and stereotactic radiotherapy techniques.

Main Methods:

• Literature review focusing on contouring guidelines and dose constraints.
• Analysis of recommendations for conventional irradiation and intensity modulation radiotherapy with classical fractionation.
• Examination of recommendations for stereotactic radiotherapy.

Main Results:

• Established contouring rules for haematopoietic and bone cortical structures.
• Summarized recommended dose constraints in a table format.
• Differentiated recommendations based on radiotherapy techniques (conventional vs. stereotactic).

Conclusions:

• Proper contouring and adherence to dose constraints for bone marrow and bone structures are crucial.
• Implementing these guidelines can mitigate risks of adverse events in patients undergoing radiation therapy.
• This review provides a comprehensive summary of current recommendations for managing these organs at risk.