Hayar M, Durankuş N K, Altun G D, Koçak Z, Uzal M C, Saynak M
Department of Radiation Oncology, Balıkesir State Hospital, Balıkesir, Turkey.
Department of Radiation Oncology, Koc University Faculty of Medicine, Istanbul, Turkey.
Cancer Radiother. 2019 Sep;23(5):408-415. doi: 10.1016/j.canrad.2019.05.014. Epub 2019 Jul 19.
Radiotherapy is a treatment method performed using ionizing radiation on cancer patients either alone or with surgery and/or chemotherapy. Although modern radiotherapy techniques provide a significant advantage in protecting healthy tissues, it is inevitable that normal tissues are also located in the areas targeted by radiations. In this study, we aimed to examine the bone mineral density changes in bone structures commonly included in the irradiated area such as, L5 vertebra, sacrum, and femur heads, in patients who have received pelvic radiotherapy; and the relationship between these changes with radiation dose.
Patients included in the study had been previously diagnosed with rectal cancer, which were operated or not. Preoperative or postoperative pelvic radiotherapy was planned for all patients. In terms of convenience when comparing with future scans, all densitometry and CT scans were performed with the same devices. Fifteen patients were included in the study. In order to determine the dose of radiation each identified area had taken after radiotherapy, the sacrum, L5 vertebra, bilateral femoral heads, and L1 regions were contoured in the CT scans in which treatment planning was done. Sagittal cross-sectional images were taken advantage of while these regions were being contoured.
Bone mineral density was evaluated with CT and dual-energy X-ray absorptiometry before and after the treatment. The regions that have theoretically been exposed to irradiation, such as L5, sacrum, left to right femur were found to have significant difference in terms of bone density. According to CT evaluation, there was a significant decrease in bone intensity of L5, sacrum, left and right femurs. Dual-energy X-ray absorptiometry assessment revealed that the whole of the left femoral head, left femur neck and Ward's region were significantly affected by radiotherapy. However, there was no significant difference in the sacrum and L5 vertebra before and after radiotherapy.
More accurate results could be achieved if the same study was conducted on a larger patient population, with a longer follow-up period. When the reduction in bone density is at maximum or a cure is likely in a long-term period, bone mineral density could be determined by measurements performed at regular intervals.
放射治疗是一种对癌症患者单独使用电离辐射，或与手术和/或化疗联合使用的治疗方法。尽管现代放射治疗技术在保护健康组织方面具有显著优势，但正常组织不可避免地也处于辐射靶向区域。在本研究中，我们旨在检查接受盆腔放疗的患者中，诸如L5椎体、骶骨和股骨头等通常包含在照射区域内的骨骼结构的骨密度变化；以及这些变化与辐射剂量之间的关系。
纳入本研究的患者既往已被诊断为直肠癌，已接受或未接受手术治疗。所有患者均计划进行术前或术后盆腔放疗。为便于与未来扫描结果进行比较，所有骨密度测定和CT扫描均使用相同设备进行。本研究共纳入15例患者。为确定放疗后每个识别区域所接受的辐射剂量，在进行治疗计划的CT扫描中，对骶骨、L5椎体、双侧股骨头和L1区域进行轮廓勾画。在勾画这些区域时利用了矢状面横截面图像。
在治疗前后，通过CT和双能X线吸收法评估骨密度。理论上接受照射的区域，如L5、骶骨、左右股骨头，在骨密度方面存在显著差异。根据CT评估，L5、骶骨、左右股骨的骨强度显著降低。双能X线吸收法评估显示，整个左侧股骨头、左侧股骨颈和沃德三角区均受到放疗的显著影响。然而，放疗前后骶骨和L5椎体无显著差异。
如果对更大规模的患者群体进行更长随访期的相同研究，可能会获得更准确的结果。当骨密度降低达到最大值或长期可能治愈时，可通过定期测量来确定骨密度。
