Voice quality is seldom the same after patients receive radiation therapy for early-stage glottic cancer. However, patients who smoke run the risk of having poorer voice quality following treatment compared to nonsmokers, according to results of a study conducted by Slovenian otorhinolaryngologists and radiation oncologists.
Researchers at the University Medical Center Ljubljana and the Institute of Oncology in Ljubljana evaluated the voice quality of 75 consecutive male patients one year or more following radiation therapy for T1 glottic carcinoma using clinically subjective and objective evaluations. Their findings were published in the December issue of Radiotherapy and Oncology (2009, Vol. 93:3, pp. 524-529).
The patients ranged in age from 19 to 88 years, with the majority (60%) older than 60. More than 90% had been smokers, with 22.7%, or 17 patients, continuing to smoke during and after radiation therapy. Only men were included because the objective analysis included fundamental frequency, which is better evaluated in men than in women, according to principal author Dr. Irena Hočevar-Boltežar of the department of otorhinolaryngology and cervicofacial surgery at the University Medical Center Ljubljana.
The men received a 2.0- or 2.2-Gy radiation dose daily over a 33- to 53-day period, for a total prescribed tumor dose of 61 to 70 Gy. All were followed up for at least 24 months after completion of treatment.
A phoniatrician perceptively evaluated the grade of hoarseness in conversations with patients, and patients themselves evaluated their voice quality based on presence or absence of voice fatigue, throat dryness, and their ability to shout and talk loudly. A videolaryngostroboscopy was conducted to evaluate the function of the vocal folds, as well as computer-based acoustic and aerodynamic analyses.
Voice quality after radiation therapy was assessed as abnormal using two measures: perceptively by a specialist (71 patients) or objectively by acoustic analysis (61 patients). This deterioration was significantly influenced by the degree of morphological alterations of the vocal cords and the continuation of smoking, as well as by throat dryness, incomplete vocal-fold closure, and supraglottic activity.
Interestingly, 55 patients disagreed; they thought that their voice was comparable or better than before radiation therapy.
The majority of patients who smoked experienced hoarseness and a dry throat, which the authors attributed to swelling of the laryngeal mucosa, and decreases in secretion of saliva and the mucous layer.
Time span following treatment impacted vocal-fold closure, with 20% who received treatment within 12 to 24 months reporting incomplete vocal-fold closure, compared with 50% whose treatment had been completed two years or more. The researchers attributed this to accelerated progression of fibrosis.
By Cynthia E. Keen
AuntMinnie.com staff writer
January 5, 2010
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