Parotid-gland-sparing 3D conformal radiotherapy in patients with bilateral radiotherapy of the head and neck region--results in clinical practice.
The aim was to improve the prediction rate of hyposalivation after using a modern 3D-conformal-radiotherapy-technique (3D-CRT) by sparing of the contralateral parotid gland. Between June 2002 and October 2006, 107 patients (90 male, 17 female, average age: 58 years) with squamous cell carcinoma of the head and neck were included in a prospective, non-randomized study. All patients were treated using 3D-CRT. Parotid function was assessed by measuring stimulated salivary flow before, during and at the end of radiotherapy, as well as 1, 6 and 12 months after radiotherapy. Measurements were converted to flow rates and normalized relative to that before treatment. Mean doses (D(mean)) were calculated from dose-volume histograms (DVHs) based on computed tomographies (CTs) for the left and right parotid gland separately. Patients were grouped according to the D(mean) of the lowest irradiated parotid gland. Group I included all patients who received a D(mean)<26Gy (n=23), group II D(mean) 26-40Gy (n=38) and group III D(mean)>40Gy (n=46). By the time of 6 months after irradiation, salivary flow rates decreased continuously during the therapy. In group I the flow rate decreased to 59%, in group II to 40% and in group III to 14%, p<0.05. One year after irradiation a recovery effect could be measured in all groups. A sufficient saliva flow rate can be proven if one parotid gland is spared with a D(mean) dose <26Gy. Approximately, one quarter of the participants showed a significant improvement.
Hey
Jeremias
J
Department of Prosthetic Dentistry, University School of Dental Medicine, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
Setz
Jürgen
J
Gerlach
Reinhard
R
Janich
Martin
M
Sehlleier
Simone
S
Schaller
Hans-Günter
HG
Gernhardt
Christian R
CR
Kuhnt
Thomas
T
D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000528:radiation effects*; D011832:Radiation Injuries / Q000517:prevention & control*; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D014987:Xerostomia / Q000209:etiology / Q000517:prevention & control*