[en] Purpose: To present the results of dose escalation using three-dimensional conformal dynamic arc radiotherapy (3D-ART) for prostate cancer. Methods and Materials: Five hundred and forty two T1-T3N0M0 prostate cancer patients were treated with 3D-ART. Dose escalation (from 76 Gy/38 fractions to 80 Gy/40 fractions) was introduced in September 2003; 32% of patients received 80 Gy. In 366 patients, androgen deprivation was added to 3D-ART. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria and Houston definition (nadir + 2) were used for toxicity and biochemical failure evaluation, respectively. Median follow-up was 25 months. Results: Acute toxicity included rectal (G1-2 28.9%; G3 0.5%) and urinary events (G1-2 57.9%; G3-4 2.4%). Late toxicity included rectal (G1-2 15.8%; G3-4 3.1%) and urinary events (G1-2 26.9%; G3-4 1.6%). Two-year failure-free survival and overall survival rates were 94.1% and 97.9%, respectively. Poor prognostic group (GS, iPSA, T), transurethral prostate resection, and dose >76 Gy showed significant association to high risk of progression in multivariate analysis (p = 0.014, p = 0.045, and p 0.04, respectively). The negative effect of dose >76 Gy was not observed (p 0.10), when the analysis was limited to 353 patients treated after September 2003 (when dose escalation was introduced). Higher dose was not associated with higher late toxicity. Conclusions: Three-dimensional-ART is a feasible modality allowing for dose escalation (no increase in toxicity has been observed with higher doses). However, the dose increase from 76 to 80 Gy was not associated with better tumor outcome. Further investigation is warranted for better understanding of the dose effect for prostate cancer

[en] Purpose: To evaluate the incidence of thyroid disorders and dose distribution to the thyroid in patients treated with radiotherapy for head-and-neck carcinomas. Methods and Materials: A retrospective evaluation of data from 73 patients treated for head-and-neck cancers in our department was performed. Thyroid function was evaluated mainly by the measurement of thyrotropin (thyroid stimulating hormone [TSH]). A retrospective analysis of treatment plans was performed for 57 patients. Percentages of thyroid glandular volume absorbing 10, 30, and 50 Gy (V10, V30, and V50 respectively) were considered for statistical analysis. Results: A majority of patients (61%) had a normal thyroid function whereas 19 patients (26%) had hypothyroidism. Mean thyroid volume was 30.39 cc. Point 3 (located at isthmus) absorbed lower doses compared with other points (p < 0.0001). Median values of V10, V30, and V50 were 92% (range, 57-100%), 75% (range, 28.5-100%), and 35% (range, 3-83%) respectively. Gender was associated with toxicity (presence of any kind of thyroid disorders) (p < 0.05), with females displaying higher levels of TSHr (relative TSH = patient's value/maximum value of the laboratory range) (p = 0.0005) and smaller thyroid volume (p 0.0012) compared with male population. TSHr values were associated with thyroid volume, and the presence of midline shielding block in the anterior field was associated with relative free thyroxine (FT4r = patient's value/maximum value of the laboratory range) values. Conclusions: Gender and thyroid volume seem to play an important role in the occurrence of thyroid toxicity, but further studies on dose-effect relationship for radiotherapy-induced thyroid toxicity are needed