Radiation-induced neuropathy in cancer survivors.

Twenty-five patients with 35 cranial nerve palsies were seen at the Fondation Curie during follow-up after radical radiotherapy for head and neck tumors. The twelfth nerve was involved in 19 cases, the tenth in nine, and the eleventh in five; the fifth and second nerves were involved once each and in the same patient. The twelfth nerve was involved alone in 16 patients and the tenth nerve alone in three, with multiple nerves involved in the remaining six patients. The palsy was noted from 12 to 145 months after diagnosis of the tumor. The latency period could be correlated with dose so that the least square fit equation representing NSD vs delay is NSD = 2598 - Delay (in months) × 4.6, with a correlation coefficient of −0.58. The distinction between tumor recurrence and radiation-induced nerve palsy is critical. It can often be inferred from the latency period but must be confirmed by observation over a period of time. Cancer 40:152–155, 1977.

Radiation-induced cranial nerve palsy.

The recurrent laryngeal nerve in its course from the brain stem to the larynx follows a path that brings it in proximity to numerous structures. These structures can interfere with its function by pressure or by disruption of the nerve caused by disease invading the nerve. The various causes of recurrent laryngeal nerve paralysis that I have observed during the past 24 years are reported. In 134 patients with recurrent laryngeal nerve paralysis, the left recurrent nerve was most commonly involved. Malignant neoplasms of the lung and pulmonary tuberculosis were the most frequent causes of the paralysis.

Causes of Recurrent Laryngeal Nerve Paralysis

Evidence-Based Practice: Evaluation and Management of Unilateral Vocal Fold Paralysis

High-dose irradiation is an effective treatment for tumors in the head and neck. Radiation-induced complications are uncommon but may result in chronic, progressive symptoms months or years after therapy. In 19 (1%) of 1,950 patients who underwent successful high-dose irradiation of head and neck tumors over a 5-year period, delayed radiation-induced changes were documented with imaging. These changes can be categorized as soft-tissue, bone, and cartilage necrosis; fibrosis leading to functional disorders; arteriopathy; central nervous system reactions, delayed myelopathy, and cranial nerve palsies; and the development of meningiomas. Radiologic features of radiation-induced soft-tissue, bone, and cartilage necrosis include inflammatory swelling adjacent to the area of involvement; deep gas-containing ulcerations; sclerotic appearance of the involved cartilages; fragmentation and sloughing of necrotic bone or cartilage; and abscess and fistula formation. Masticator muscle fibrosis appears as an area of diffusely increased signal intensity on T2-weighted images and of enhancement on postcontrast T1-weighted images. Radiation arteriopathy may manifest as occlusion, subocclusive sclerotic or atheromatous plaque, localized mural thrombus, aneurysm, or, rarely, spontaneous rupture. In central nervous system reactions, imaging findings include demyelination foci in the white matter, focal radiation necrosis, and severe brain atrophy. Radiation-induced meningiomas display the same imaging features as non-radiation-induced meningiomas at computed tomography, magnetic resonance imaging, and angiography, although follow-up examinations may reveal their more aggressive biologic behavior. Knowledge of the radiologic appearance of radiation-induced changes may prevent misinterpretations and facilitate treatment.

A J Ballantyne

Papers

Breast cancer and vocal cord paralysis.