Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Radiation Oncology cung cấp cho các bạn kiến thức về ngành y đề tài: Dose distribution in the thyroid gland following radiation therapy of breast cancer-a retrospective study. | Johansen et al. Radiation Oncology 2011 6 68 http content 6 1 68 RADIATION ONCOLOGY RESEARCH Open Access Dose distribution in the thyroid gland following radiation therapy of breast cancer-a retrospective study S Johansen1 KV Reinertsen2 3 K Knutstad4 DR Olsen5 and SD Fossa6 Abstract Purpose To relate the development of post-treatment hypothyroidism with the dose distribution within the thyroid gland in breast cancer BC patients treated with loco-regional radiotherapy RT . Methods and materials In two groups of BC patients postoperatively irradiated by computer tomography CT -based RT the individual dose distributions in the thyroid gland were compared with each other Cases developed post-treatment hypothyroidism after multimodal treatment including 4-field RT technique. Matched patients in Controls remained free for hypothyroidism. Based on each patient s dose volume histogram DVH the volume percentages of the thyroid absorbing respectively 20 30 40 and 50 Gy were then estimated V20 V30 V40 and V50 together with the individual mean thyroid dose over the whole gland MeanTotGy . The mean and median thyroid dose for the included patients was about 30 Gy subsequently the total volume of the thyroid gland VolTotGy and the absolute volumes cm3 receiving respectively 30 Gy and 30 Gy were calculated Vol 30 and Vol 30 and analyzed. Results No statistically significant inter-group differences were found between V20 V30 V40 and V50Gy or the median of MeanTotGy. The median VolTotGy in Controls was times above VolTotGy in Cases p with large inter-individual variations in both groups. The volume of the thyroid gland receiving 30 Gy in Controls was almost times greater than the comparable figure in Cases. Conclusions We concluded that in patients with small thyroid glands after loco-radiotherapy of BC the risk of post-treatment hypothyroidism depends on the volume of the thyroid gland. Keywords Breast cancer Radiotherapy hypothyroidism .
