Main Session
Sep 29
SS 25 - Nonmalignant 1: Advances in Radiotherapy for Nonmalignant Indications

251 - Radiation Therapy in Head and Neck Amyloidosis: A 25-Year Institutional Experience

03:40pm - 03:50pm PT
Room 310-312

Presenter(s)

Jared Hobson, MD, BSN, RN - Mayo Clinic Rochester, Rochester, MN

J. N. Hobson1, D. K. Ebner1, D. J. Ma1, S. C. Lester1, S. Bayan2, R. S. Go3, W. Breen1, D. C. Ekbom4, J. M. Wilson1, T. D. Malouff1, D. M. Routman1, and M. A. Neben-Wittich1; 1Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 2Department of Otolaryngology, Mayo Clinic, Rochester, MN, 3Department of Neurology, Mayo Clinic, Rochester, MN, 4Mayo Clinic, Rochester, MN

Purpose/Objective(s):

Amyloidosis is a rare disorder characterized by misfolded protein deposition, leading to organ dysfunction or obstructive symptoms. Localized disease is typically managed with surgery or laser excision, but recurrence is common. External beam radiation therapy (EBRT) has shown promise with limited case reports and series noting symptom relief and disease stability. This study aims to evaluate the efficacy of EBRT in a larger cohort of head and neck (H&N) patients and its potential as a definitive or adjuvant therapy.

Materials/Methods:

A retrospective review of H&N patients treated with EBRT for biopsy-proven amyloidosis between 1999 and 2024 at a single institution was performed. Data on age, gender, amyloidosis type, systemic involvement, plasma cell dyscrasia, prior treatments, symptoms, and radiation regimen were collected. Outcomes were assessed through symptom changes, toxicities, and organ responses based on imaging, pulmonary function tests, and time to next intervention or death.

Results:

26 patients were assessed with 32 EBRT courses delivered, with a median follow-up of 27.6 months (range: 0–300.9). Treated sites included the laryngo-tracheal-bronchial (2), tracheobronchial (16), laryngotracheal (2), larynx (3), trachea (1), bronchi (2), nasopharynx (2), orbit (2), and trigeminal nerves (2). All patients had AL-type amyloidosis; 1 had systemic amyloidosis (SA) and 2 had a plasma cell dyscrasia with MGUS. 14 patients had prior local treatments. The most common EBRT regimen was 20 Gy in 10 fractions (28 courses in 22 patients), with alternate dosing ranging from 30 Gy in 10 fractions to 41.4 Gy in 23 fractions. Of the 32 courses, 21 (66%) resulted in symptom improvement. Of those with follow-up, 28 of 30 courses (93%) showed stable disease or objective response (15 stable, 13 responding), 2 courses showed immediate growth (1 nasopharynx, 1 tracheobronchial) and 2 were not reassessed. 3 patients (12%) with stability or response later developed local recurrence or progression, all tracheobronchial. All who progressed received 20 Gy in 10 fractions, with 1 patient having 2 progressions with 3 EBRT courses. None of the 4 patients with doses above 20 Gy had a recurrence. 2 patients had masses described as bulky or >7.5 cm, both developing local progression. 4 patients had distant progression, 1 with SA and 1 with MGUS. Three patients underwent elective surgery for persistent symptoms after EBRT, with no signs of progression. Toxicities were mild, mainly grade 1 esophagitis and fatigue, with 1 grade 3 tracheoesophageal fistula, likely due to disease invasion.

Conclusion:

This study supports the efficacy of EBRT in H&N amyloidosis, providing stability and durable local control with minimal toxicity. EBRT can be a reasonable definitive treatment or beneficial as an adjuvant therapy for symptomatic patients or those with bulky disease after other interventions. Dose escalation and multi-modality approaches could be explored in future studies to optimize outcomes.