Int Poster J Dent Oral Med 2011, Vol 13 No 2, Poster 532
Changes of parotid gland function due tosimultaneous radiochemotherapy
Dr. Jeremias Hey, Dr. Arne Boeckler, Prof. Dr. Jürgen Setz,
Universitätspoliklinik für Zahnärztliche Prothetik, Martin-Luther-Universität Halle-Wittenberg, Germany
Dr. Reinhard Gerlach,
Universitätsklinik für Strahlentherapie, Universitätsklinikum Halle, Germany
PD Dr. Christian Gernhardt,
Universitätspoliklinik für Zahnerhaltung, Martin-Luther-Universität Halle-Wittenberg, Germany
PD Dr. Thomas Kuhnt,
Universitätsklinik für Strahlentherapie, Universitätsklinikum Rostock, Germany
July 14 - 17, 2010
88th General Session & Exhibition of the IADR Barcelona
To investigate complication probability on parotid gland tissue due to simultaneous radiochemotherapy [XRCT] with cisplatin.
Material and Methods
Patients treated either with radiotherapy [XRT] (n = 61) or XRCT with cisplatin (n = 36) for head and neck cancer were prospectively evaluated. Dose and volume distributions of the parotid glands were recorded in dose-volume histograms. Stimulated salivary flow rates were measured before, at the 2nd and 6th week during and at 4 weeks and 6 months after the treatment. The data were calculated based on the normal tissue complication probability [NTCP] model of Lyman. Complication was defined as a reduction of the salivary flow rate >75% of the pre-treatment flow rate.
|Abbreviations: EUD = Equivalent Uniform Dose Homogeneous dose distribution with equivalent damage likelyhood
In both groups the salivary flow rate already dropped considerably during the radiation therapy. The salivary flow rates for simultaneous radiochemotherapy decreases further than for radiotherapy. Data of relative salivary flow rate differ significantly at the 6th week of treatment (p = 0.02). The dose leading to a complication probability of 50% [TD50] was found to be 32.2Gy/4 weeks and 32.1Gy/6 months for XRCT and 41.1Gy/4weeks and 39.6Gy/6 months for XRT. The tolerated dose for XRCT was at least 7-8Gy lower than for XRT alone at TD50.
|Course of relative salivary flow at repeated assessment for radiotherapy and simultaneous radiochemotherapy Abbreviations: XRT = radiotherapy; XRCT = radiochemo-therapy
||Correlation between mean dose of the parotid glands and and the relative salivary flow rate. Abbreviations: XRT = radiotherapy XRCT = radiochemo-therapy r = Pearson's correlation coefficient
|NTCP curves 6 months post treatment with their 95% intervals of confidence: radiotherapy and simultaneous radiochemotherapy
|Parotid gland sparing with IMRT Mean dose right parotid gland 35 Gy. Mean dose left parotid gland 19 Gy.
It seems that XRCT cause a higher probability of parotid gland tissue damage. Radiotherapy planning approaches such as Intensity-Modulated Radiation Therapy may be partiticularly important for parotid sparing in radiochemotherapy due to cisplatin-related increased radiosensitivity of glands.
This Poster was submitted by Dr. Jeremias Hey.
Dr. Jeremias Hey
Department of Prosthodontics, Centre for Dentistry and Oral Medicine
Poliklinik für Prothetik
Grosse Steinstrasse 19
06108 Halle /Saale