Laryngeal Carcinomas: CT Appearance after Radiation Therapy

Abstract

Current treatment of head and and neck carcinomas includes also Radiation Therapy (RT). Control with RT allows the patient to retain a functioning organ in cases in which surgical cure may require an extensive demolition. Consequently a growing number of selected patients are treated with RT. To evaluate the CT appearance of laryngeal carcinomas treated with RT and the ability of Computed Tomography (CT) to differentiate persistent or residual tumor from radio-induced changes of soft tissues.

Pre- and post-treatment CT examinations (n = 325) of 132 patients with primary laryngeal cancers treated with RT (4500–7500 cGy) were retrospectively evaluated.

We subdivide the patients in three groups on the basis of the differences in the CT appearance of the primary tumors treated with RT 1) Responders (42): complete resolution of tumor or reduction in tumor size = or > 75%; 2) Non-Responders (55): persistent tumor or residual mass with reduction in tumor size — or < 50%. 3) Partial Responders (35): persistent residual mass with reduction in tumor size from 50% to 75% or persistent asimmetry of the mucosal surface.

There are some points to analyse in the interpretation of CT imaging of post-treated head and neck region: 1) Transient changes of irradiated soft tissues are more prominent during the first three month after RT. 2) Persistent changes are subgrouped in: a) Superficial (skin and platysmal thickening, reticulation of subcutaneous fat); b) Glandular (major salivary glands adenitis and fatty degeneration); c) Deep (reticulation and fibrous degeneration of anterior and posterior cervical and perivascular fat); d) Visceral (increased en-hancement of the pharyngeal mucosa and thickening of posterior pharyngeal wall, epiglottis, aryepiglottic folds, false vocal cords, anterior and posterior commissures, subglottic larynx, increased attenuation of paralaryngeal fat). 3) Progressive arytenoid cartilage sclerosis is indicative of a poor outcome. 4) The patients of the third group may be followed also with seriated CT, because they have a significant percentage of recurrence.

Keywords

laryngeal carcinoma CT x-ray therapy

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