A comparison of mean parotid gland dose with measures of parotid gland function after radiotherapy for head-and-neck cancer: Implications for future trials

Journal Article · Tue Nov 15 04:00:00 EST 2005 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2005.04.023· OSTI ID:20706241

Roesink, Judith M ^[1]; Schipper, Maria ^[2]; Busschers, Wim ^[2]; Raaijmakers, Cornelis P.J.; Terhaard, Chris H.J. ^[1]

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1. Department of Radiotherapy, University Hospital Utrecht, University Medical Center Utrecht, Utrecht (Netherlands)
2. Center for Biostatistics, Utrecht University, Utrecht (Netherlands)

Purpose: To determine the most adequate parameter to measure the consequences of reducing the parotid gland dose. Methods and Materials: One hundred eight patients treated with radiotherapy for various malignancies of the head and neck were prospectively evaluated using three methods. Parotid gland function was objectively determined by measuring stimulated parotid flow using Lashley cups and scintigraphy. To assess xerostomia-related quality of life, the head-and-neck cancer module European Organization for Research and Treatment of Cancer QLQ (Quality of Life Questionnaire) H and N35 was used. Measurements took place before radiotherapy and 6 weeks and 12 months after the completion of radiotherapy. Complication was defined for each method using cutoff values. The correlation between these complications and the mean parotid gland dose was investigated to find the best measure for parotid gland function. Results: For both flow and scintigraphy data, the best definition for objective parotid gland toxicity seemed to be reduction of stimulated parotid flow to {<=}25% of the preradiotherapy flow. Of all the subjective variables, only the single item dry mouth 6 weeks after radiotherapy was found to be significant. The best correlation with the mean parotid gland dose was found for the stimulated flow measurements. The predictive ability was the highest for the time point 1 year after radiotherapy. Subjective findings did not correlate with the mean parotid dose. Conclusions: Stimulated flow measurements using Lashley cups, with a complication defined as flow {<=}25% of the preradiotherapy output, correlated best with the mean parotid gland dose. When reduction of the mean dose to the parotid gland is intended, the stimulated flow measurement is the best method for evaluating parotid gland function.

• OSTI ID: 20706241
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 4 Vol. 63; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CARCINOMAS
GLANDS
HEAD
NECK
ORAL CAVITY
PATIENTS
RADIATION DOSES
RADIOTHERAPY
SCINTISCANNING
TOXICITY