Treatment of Localized Amyloid Light Chain Amyloidosis With External Beam Radiation Therapy.

Abstract

Localized amyloidosis is a condition characterized by deposits of fibrillary proteins confined to a single organ. The most common subtype is amyloid light chain amyloidosis, which is caused by secretion of amyloidogenic light chain by a monoclonal population of plasma cells. We present a review and discussion of the literature in the context of a case presentation of localized amyloid light chain amyloidosis of the nasopharynx treated with radiation alone. We reviewed literature relevant to this topic from 1970 to the present. Relevant studies, reports, and articles were summarized in table form. Surgical resection has historically been the primary therapeutic modality for these patients, with radiation being reserved for recurrent lesions or for those unfit for surgery. Although the data are limited to small retrospective series, radiation has been shown to provide good control with mild toxicity that is as good as or better than surgery. Doses range from 20 to 45 Gy, conventionally fractionated. There is no known risk of progression to systemic disease without local therapy. We recommend local therapy for symptomatic patients after systemic disease has been excluded. We generally recommend radiation in the setting of recurrent lesions, unacceptable toxicity with surgery, poor surgical candidates, and as the initial modality in select patients (elderly individuals with bothersome but nonobstructive lesions).