[Normal tissue tolerance to external beam radiation therapy: peripheral nerves].

Area of Science:

• Oncology
• Neurology
• Radiation Oncology

Background:

• Radiotherapy can lead to delayed onset plexopathies and peripheral neuropathies.
• These nerve injuries are frequently observed following irradiation of the breast, pelvis, and limbs for various cancers.
• Peripheral nerves and plexuses are susceptible to radiation-induced damage, with dose being a critical factor.

Purpose of the Study:

• To review the occurrence and characteristics of radiation-induced nerve damage.
• To identify clinical situations and dose thresholds associated with plexopathies and peripheral neuropathies.
• To discuss factors influencing the risk of late radiation complications in nerves.

Main Methods:

• Literature review of studies on radiotherapy-induced nerve injuries.
• Analysis of clinical data regarding irradiation sites and doses.
• Examination of dose-response relationships and influencing factors.

Main Results:

• Nerve damage appears progressively years after radiotherapy, especially after breast, pelvic, and limb irradiation.
• A maximum tolerable dose threshold of 60 Gy is suggested, with significant pain occurrence differences between 50 and 60 Gy.
• Fractionation and high fraction doses influence the incidence of late radiation effects.

Conclusions:

• Radiotherapy dose, fractionation, and patient-specific factors (e.g., diabetes, vascular disease) are crucial in the development of late nerve complications.
• Understanding dose limits is essential for minimizing the risk of radiation-induced plexopathies and peripheral neuropathies.
• Further research is needed to refine dose constraints and management strategies for these debilitating side effects.