Radiation-induced Peripheral Neuropathy.

It has been thought that adult nervous tissues show a remarkable degree of resistance to injury by x rays. Clemedson and Nelson (1960), after a comprehensive review of the literature, state: " Nervous tissues, especially of adult animals, show a remarkable radio-resistance." In the past few years, however, experimental work on animals (Lander, 1959; Innes and Carsten, 1961) suggests that delayed degeneration of spinal nerves can follow doses of x rays which are near the clinical range. Clinically, also, peripheral nerves have in the past been regarded as relatively radio-resistant. Damage to nerves from the high dose in the vicinity of radium needles was, of course, a well-recognized complication of the Keynes technique for radium implantation of the axillary contents. However, with the use of kilovoltage x-ray therapy in the past, the skin tolerance was the limiting factor in dosage, and damage to peripheral nerves was rarely seen. More recently, however, with the development of megavoltage x-ray machines, peak dosage is below the skin and the risk of nerve damage is therefore increased. This report presents evidence of peripheral-nerve damage in a group of patients treated by megavoltage x-ray therapy after operation for carcinoma of the breast.