Radiotherapy: principles and application with special attention to the head and neck region

Radiotherapy plays an important role in the treatment of cancer and is often applied with curative intent. With the help of modern technical equipment irradiation can be delivered at the tumour localization with maximal sparing of the surrounding normal tissues. Also can differences in the biological effects of irradiation between tumour and normal tissue be utilized to optimize treatment by increasing the chances for cure while limiting side effects. The complex anatomy of the head and neck requires that irradiation is delivered with high precision. Intensive support of the patient before, during, and after treatment is of great importance to control side effects.     

Comparison of different methods of CAIX quantification in relation to hypoxia in three human head and neck tumor lines.

PURPOSE: In head and neck cancer, it has been shown that hypoxic tumors respond poorly to therapy. Methods to identify hypoxic tumors are, therefore, of importance to select patients for oxygenation modifying or other intensified treatments. The aim of this study was to compare tumor cell hypoxia assessed by the hypoxic cell marker pimonidazole (PIMO) with expression of the endogenous hypoxia-related marker carbonic anhydrase IX (CAIX) in three human head and neck tumor lines. MATERIAL AND METHODS: Forty-five tumors of three human head and neck tumor lines, SCCNij3, SCCNij59 and MEC82, xenografted in athymic mice, were used. CAIX was quantified by biodistribution (% injected dose/g tumor) after injecting 3-5 microl 111In-labeled G250 mouse antibody 3 days prior to euthanizing. In a tissue section from the same tumor, fractions of tumor area positive for PIMO, CAIX and Hoechst 33342 (perfusion marker) were assessed after immunohistochemical staining, using a digital image analysis system. RESULTS: SCCNij3 and MEC82 were relatively hypoxic tumor lines with fractions of tumor area positive for pimonidazole of 0.16 and 0.15, respectively. SCCNij59 was a better-oxygenated tumor line with a PIMO-fraction of 0.03. The three tumor lines showed different levels and patterns of CAIX immunohistochemical staining, but only in MEC82 there was a good correlation between PIMO-fraction and CAIX-fraction (r2=0.92, P<0.0001). Correlations between 111In-G250 uptake and CAIX-fraction or PIMO-fraction within tumor lines were weak or absent. CONCLUSIONS: Assessment of CAIX expression depends largely on the techniques and tumor lines used. Furthermore, the immunohistochemical staining pattern of CAIX relative to PIMO differs between human tumor lines of similar anatomical origin. Therefore, the use of CAIX as endogenous marker of tumor hypoxia remains questionable.     

Tumor control of cervical lymph node metastases of unknown primary origin: the impact of the radiotherapy target volume

European Archives of Oto-Rhino-Laryngology - Debate on the extent of treatment of neck metastasis of cancer of unknown primary tumors (CUPs) is still ongoing. In two Dutch tertiary referral...