Tongue surface model can predict radiation tongue mucositis due to intensity-modulated radiation therapy for head and neck cancer.

Acute radiation tongue mucositis has a profound effect on talking and eating. We examined whether the dose-volume histogram obtained from the tongue surface model correlates with mucositis severity, and whether it is useful for predicting acute radiation tongue mucositis in patients with head and neck cancer treated with intensity-modulated radiation therapy. Thirty-six patients who received intensity-modulated radiation therapy for head and neck cancer were analysed for acute radiation tongue mucositis according to the Common Terminology Criteria for Adverse Events, version 4.0, as well as the Radiation Therapy Oncology Group scoring systems. The corresponding high-dose locations in anatomical sub-regions in the tongue surface model and the development of high-grade acute radiation tongue mucositis were compared. The mucositis sites coincided with the high-dose anatomical sub-regions in the tongue surface model. There was a clear dose-response relationship between the mean dose to the tongue and the acute radiation tongue mucositis Radiation Therapy Oncology Group grade. According to the dose-volume histogram, patients receiving 16.0-73.0 Gy to the tongue were susceptible to grade 2-3 toxicity. The tongue surface model can predict the site and severity of acute radiation tongue mucositis. In future, radiation treatment plans ccould be optimized using this model.

Effect of hyperthermia combined with external radiation therapy in primary non-small cell lung cancer with direct bony invasion.

PURPOSE: Local control in lung cancer directly invading the bone is extremely poor. Effects of regional hyperthermia combined with conventional external beam radiation therapy were evaluated. MATERIALS AND METHODS: Thirteen patients with non-small lung cancer (NSCLC) with direct bony invasion were treated with hyperthermia plus irradiation (hyperthermia group). The treatment outcome was compared with the historical treatment results in 13 patients treated with external radiation therapy alone (radiation alone group). In patients with no distant metastasis, radiation therapy at a total dose of 60-70 Gy was administered to both groups. Hyperthermia was performed for 45-60 min immediately after irradiation for two-four sessions with radiofrequency capacitive heating devices. RESULTS: For primary response, 10 of the 13 tumours responded to the treatment (3 CR, 7 PR) in the hyperthermia group, whereas seven tumours responded (1 CR, 6 PR) in the radiation alone group. The 2-year local recurrence-free survival rate for clinical M(0) patients in the hyperthermia group and that in the radiation alone group were 76.1 and 16.9%, respectively. Three patients died of distant metastases within 2 years in the hyperthermia group, but two out of three tumours histologically disappeared, even in the autopsy examination. The 2-year overall survival rate for clinical M(0) patients in the hyperthermia group and that in the radiation alone group were 44.4 and 15.4%, respectively. No severe pulmonary complication was observed in either group. CONCLUSIONS: Regional hyperthermia combined with conventional irradiation could be a tool to improve local control in patients with NSCLC deeply invading the chest wall.

Genistein, a tyrosine kinase inhibitor, enhanced radiosensitivity in human esophageal cancer cell lines in vitro: possible involvement of inhibition of survival signal transduction pathways.

PURPOSE: The effect of genistein, a tyrosine kinase inhibitor, on radiosensitivity was examined, especially focusing on "survival signal transduction pathways." METHODS AND MATERIALS: Two human esophageal squamous cell cancer cell lines, TE-1 (p53, mutant) and TE-2 (p53, wild), were used. Radiosensitivity was determined by clonogenic assay, and activation of survival signals was examined by Western blot. RESULTS: Genistein (30 microM) greatly enhanced radiosensitivity in these cell lines by suppressing radiation-induced activation of survival signals, p42/p44 extracellular signal-regulated kinase and AKT/PKB. Significant increase in the percentage of apoptotic cells and increased poly[ADP-ribose] polymerase cleavage were observed in TE-2, but not in TE-1 even after combination of genistein with irradiation. In terms of changes in expression of p53-related proteins, increase in expression of Bax and decrease in that of Bcl-2 were observed in TE-2 but not in TE-1, suggesting that the main mode of cell death induced by genistein in a cell line with wild type p53 differed from that with mutant p53. CONCLUSIONS: This study suggested that survival signals, including p42/p44 ERK and AKT/PKB, may be involved in determining radiosensitivity, and genistein would be a potent therapeutic agent that has an enhancing effect on radiation.

Biological cell survival mapping for radiofrequency intracavitary hyperthermia combined with simultaneous high dose-rate intracavitary irradiation.

We examined the best way to combine recently developed radiofrequency intracavitary hyperthermia with simultaneous high dose-rate intracavitary brachytherapy in an original experimental model. Temperature distribution was measured with an experimental phantom which was immersed in a water bath with the temperature controlled at 37 degrees C. Radiation dose distribution was calculated with a treatment-planning computer. Cell survival was measured by colony assay with HeLa-TG cells in vitro. Radiation dose response at 1 - 7 Gy and time response with hyperthermia in the range of 40 - 46 degrees C were estimated. Radiation dose-response curves in simultaneous treatment with hyperthermia for 30 min at 37 to 46 degrees C were estimated and the surviving fractions in combined treatment were plotted against temperature. For intracavitary radiation alone, cell survival rates increased with increasing distance from the source. For intracavitary hyperthermia alone, the maximum temperature was observed at a depth of 13 mm from the surface of the applicator under suitable treatment conditions. Homogeneous cell killing from the surface of the applicator to a tumor depth of 13 mm was observed under a specific treatment condition. Our experimental model is useful for evaluating the best simultaneous combined treatment.