Comparison of three-dimensional vs. conventional radiotherapy in saving optic tract in paranasal sinus tumors

PURPOSE

To assess the possibility of delivering a homogeneous irradiation with respect to maximal tolerated dose to the optic pathway for paranasal sinus (PNS) tumors.

METHODS

Treatment planning with conformal three-dimensional (3D) and conventional two-dimensional (2D) was done on CT scans of 20 patients who had early or advanced PNS tumors. Four cases had been previously irradiated. Dose-volume histograms (DVH) for the planning target volume (PTV) and the visual pathway including globes, chiasma and optic nerves were compared between the 2 treatment plannings.

RESULTS

The area under curve (AUC) in the DVH of the globes on the same side and contralateral side of tumor involvement was significantly higher in 2D planning (p <0.05), which caused higher integral dose to both globes. Also, the AUC in the DVH of chiasma was higher in 2D treatment planning (p=0.002). The integral dose to the contralateral optic nerve was significantly lower with 3D planning (p=0.007), but there was no significant difference for the optic nerve which was on the same side of tumor involvement (p >0.05). The AUC in the DVH of PTV was not significant (201.1 + or - 16.23 mm(3) in 2D planning vs. 201.15 + or - 15.09 mm(3) in 3D planning). The volume of PTV which received 90% of the prescribed dose was 96.9 + or - 4.41 cm(3) in 2D planning and 97.2 + or - 2.61 cm(3) in 3D planning (p >0.05).

CONCLUSION

3D conformal radiotherapy (RT) for PNS tumors enables the delivery of radiation to the tumor with respect to critical organs with a lower toxicity to the optic pathway.

Benzydamine for prophylaxis of radiation induced oral mucositis in head and neck cancers: Double-blind clinical trial

9042

Background: Oral mucositis is one of the most common adverse effects of radiotherapy in head and neck tumors. We determined the efficacy of oral rinse benzydamine in prevention of radiation induced mucositis. Methods: Patients with head and neck cancers were enrolled in a randomize, placebo-controlled clinical trail to receive either benzydamine or placebo. All the cases received at least 50 Gy radiation to the oral cavity and oropharyngeal areas. The end points were comparison of highest grade of mucositis at the end of radiotherapy, frequency of grade 2 or more, the interval days to establishing grade 2 in the groups. Results: 100 patients with head and neck cancers were randomized in this trail. At the end of the study, 19 patients were excluded of the analysis due to minor side effects of drug, or stopping the radiotherapy. In 39 cases in the treated group, the frequency of mucositis grade 3 or more was 43.6% (17 cases) in contrast to 78.6% (33 cases) in 42 cases in the placebo group, which was significant (p=0.001). Mucositis grade 3 or more was 2.6 times frequent in placebo group (CI=95%, relative risk=1.38–5). At the end of RT, at least 42% of the treated group had mucositis grade 3 or more in contrast to at least 76% in the control group which was statistically significant. Intensity of mucositis was increased up to forth week of treatment in both groups to grade 2. In the treated group the grade of mucositis was approximately constant to the end of therapy; but in the control group it raised to grade 3 (p<0.001). The highest grade of mucositis during the treatment time was significantly different between two groups (p=0.049). The median interval days of establishing grade 2 mucositis was 3.6 days sooner in the placebo group (p=0.12). Conclusions: According to these results it seems that oral rinse benzydamine was effective, safe, and well tolerated for prophylactic treatment of radiation-induced oral mucositis in head and neck tumors.

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