A Review of Recent Developments in Image-Guided Radiation Therapy in Cervix Cancer

Brachytherapy is an essential part of radiotherapy treatment for cervical cancer. Over the decades, it has evolved from manual loading of radium and caesium to remote after-loaders and from low-dose and medium-dose rates to high-dose rates. Over the past 10?years, 3D image-based Brachytherapy has evolved and established itself as the gold standard, improving local control and overall survival, and significantly reducing toxicity. In this article, we review some of the available literature on gynaecologic brachytherapy, more specifically on topics such as dose rates, high-dose-rate/pulsed-dose-rate (HDR/PDR) brachytherapy and image-based brachytherapy (IBBT), and present some of the evidence that establishes IBBT     

A Systematic Overview of Radiation Therapy Effects in Cervical Cancer (Cervix Uteri)

A systematic review of radiation therapy trials in several tumour types was performed by The Swedish Council of Technology Assessment in Health Care (SBU). The procedures for evaluation of the scientific literature are described separately (Acta Oncol 2003; 42: 357-365). This synthesis of the literature on radiation therapy for cervical cancer is based on data from 1 meta-analysis and 34 randomized trials. In total, 35 scientific articles are included, involving 7 952 patients. The results were compared with those of a similar overview from 1996 including 34 024 patients. The conclusions reached can be summarized in these points: There are limited scientific data supporting that postoperative pelvic radiotherapy improves disease-free survival in early cervical cancer. No firm conclusion can be drawn.There is moderate scientific evidence that external beam radiotherapy combined with brachytherapy gives a similar disease-free and overall survival rate as radical hysterectomy in early cervical cancer.There is strong scientific evidence that concomitant radiochemotherapy improves disease-free and overall survival compared to radiotherapy alone in early cervical cancer.The NCI has recently published an announcement stating that cisplantin-based chemotherapy should be used concomitantly with radiotherapy in cervical cancer. No solid documentation for this statement can be found concerning locally advanced stages (>IIB).There is a strong scientific evidence that cisplatin-based chemotherapy given concomitantly with radiotherapy is superior to concomitant chemotherapy with hydroxyurea.There is no scientific evidence to show that neoadjuvant chemotherapy followed by radiotherapy improves disease-free or overall survival compared to radiotherapy alone in patients with localized cervical cancer.There is moderate scientific evidence that high-dose-rate brachytherapy gives the same local control rate as low-dose-rate brachytherapy but with fewer rectal complications.     

Intensity-Modulated Radiation Therapy for Breast Cancer

Over the past 2 decades, numerous advances and innovations have occurred in all technical aspects of radiation therapy (RT), including three-dimensional (3D) treatment planning, conformal radiation delivery, intensity-modulated radiation therapy (IMRT), patient immobilization, and precise treatment verification. Despite incredible progress on all fronts, standard RT for breast cancer has changed very little and has not fully exploited many of the advances commonly used to treat most other malignancies. Increasing data have also accumulated, indicating that dose non-uniformities within the breast with traditional RT techniques can be greater than in many other anatomic sites. These significant dose inhomogeneities can produce unnecessary acute and chronic toxicities as well as unacceptable long-term cosmetic results. In addition, the lack of accurate verification of target volume coverage (e.g. lumpectomy cavity or chest wall) may result in diminished tumor control. In this review, we demonstrate how 3D treatment planning combined with IMRT using our in-house step and shoot, multi-leaf collimator (sMLC) technique for tangential whole-breast RT can be an efficient and reliable method for achieving a more uniform dose throughout the whole breast. Strict dose-volume constraints can be readily met in the majority of patients, resulting in both improved coverage of breast tissue as well as a potential reduction in acute and chronic toxicities. Since the median number of sMLC segments required per patient is only eight, treatment time is not significantly increased. As a result, widespread implementation of this technology can be achieved for most patients with breast cancer with minimal imposition on clinic resources and time constraints. In addition, since lung and heart volumes are also identified, doses to these structures can be maintained at predefined ‘safe’ levels by the treating physician. With the increased use of potentially cardiotoxic drugs in a substantial number of patients with breast cancer, the use of RT in these patients will take on greater significance. It remains to be seen whether the previously noted improvements in survival of patients with postmastectomy RT can be maintained using ‘standard’ techniques combined with these cardiotoxic drugs or whether more technologically sophisticated RT approaches (e.g. IMRT) will be required.     

前列腺癌放射治疗进展

20世纪50年代用外照射的方法广泛治疗前列腺癌，尽管放疗技术有某些改进，但常规放射治疗的剂量只是65Gy-70Gy，常规外射线治疗最大程度也只能控制局限的前列腺癌，最近研究用三维适形放射治疗（3-DCRT）和调强放射治疗（IMRT），以及同时使用雄激素抑制剂，几个随机试验的资料认为，局部进展，具高危不利因素的前列腺癌的局部失败率明显下降，20世纪80年代，前列腺癌近距离治疗出现惊人的发展，放射源可以准确插植，并有剂量优化，2种同位素适用于低剂量持久性粒子植入，即^125I和^103Pd。这项技术可以充分满足前列腺癌所需剂量，且直肠和膀胱受到很小剂量照射。     

放射治疗在早期乳腺癌中的应用

目前保乳治疗已经成为早期乳腺癌的标准治疗方案,而放射治疗在保乳治疗中的作用也日益得到体现.由于传统的全乳放射治疗存在着诸多的劣势,所以近些年来,部分乳腺放疗逐渐为人们所重视.相对于传统全乳腺照射,部分乳腺放疗可使患者的保乳治疗更快捷,且降低了远期并发症的风险.但是部分乳腺放疗研究的长期结果尚缺乏,而且病例选择及放疗实施也存在很多不确定性.部分乳腺放疗是有前途的方法,但在病例选择治疗技术以及处方剂量上仍有很多工作要完成.本文对放射治疗在早期乳腺癌保乳治疗中的应用情况做一综述.     

乳腺癌保乳手术后的放射治疗

早期乳腺癌保留乳腺手术后的放射治疗,是欧美国家治疗早期乳腺癌的主要方法之一。本文综述了这种方法近10年来在照射方法、应用技术、与化疗结合适应证等方面的进展。