Impact of different setup approaches in image-guided radiotherapy as primary treatment for prostate cancer

Aim

The goal of this study was to assess the impact of different setup approaches in image-guided radiotherapy (IMRT) of the prostatic gland.

Methods

In all, 28 patients with prostate cancer were enrolled in this study. After the placement of an endorectal balloon, the planning target volume (PTV) was treated to a dose of 70 Gy in 35 fractions. A simultaneously integrated boost (SIB) of 76 Gy (2.17 Gy per fraction and per day) was delivered to a smaller target volume. All patients underwent daily prostate-aligned IGRT by megavoltage CT (MVCT). Retrospectively, three different setup approaches were evaluated by comparison to the prostate alignment: setup by skin alignment, endorectal balloon alignment, and automatic registration by bones.

Results

A total of 2,940 setup deviations were analyzed in 980 fractions. Compared to prostate alignment, skin mark alignment was associated with substantial displacements, which were ≥?8 mm in 13?%, 5?%, and 44?% of all fractions in the lateral, longitudinal, and vertical directions, respectively. Endorectal balloon alignment yielded displacements ≥?8 mm in 3?%, 19?%, and 1?% of all setups; and ≥?3 mm in 27?%, 58?%, and 18?% of all fractions, respectively. For bone matching, the values were 1?%, 1?%, and 2?% and 3?%, 11?%, and 34?%, respectively.

Conclusion

For prostate radiotherapy, setup by skin marks alone is inappropriate for patient positioning due to the fact that, during almost half of the fractions, parts of the prostate would not be targeted successfully with an 8-mm safety margin. Bone matching performs better but not sufficiently for safety margins ≤?3 mm. Endorectal balloon matching can be combined with bone alignment to increase accuracy in the vertical direction when prostate-based setup is not available. Daily prostate alignment remains the gold standard for high-precision radiotherapy with small safety margins.     

Hypofractionated radiotherapy in the treatment of early breast cancer

Radiotherapy (RT) after tumorectomy in early breast cancer patients is an established treatment modality which conventionally takes 6-7 wk to complete. Shorter RT schedules have been tested in large multicentre randomized trials and have shown equivalent results to that of standard RT (50 Gy in 25 fractions) in terms of local tumor control, patient survival and late post-radiation effects. Some of those trials have now completed 10 years of follow-up with encouraging results for treatments of 3-4 wk and a total RT dose to the breast of 40-42.5 Gy with or without boost. A reduction of 50% in treatment time makes those RT schedules attractive for both patients and health care providers and would have a significant impact on daily RT practice around the world, as it would accelerate patient turnover and save health care resources. However, in hypofractionated RT, a higher (than the conventional 1.8-2 Gy) dose per fraction is given and should be managed with caution as it could result in a higher rate of late post-radiation effects in breast, heart, lungs and the brachial plexus. It is therefore advisable that both possible dose inhomogeneity and normal tissue protection should be taken into account and the appropriate technology such as three-dimensional/intensity modulated radiation therapy employed in clinical practice, when hypofractionation is used.     

High-dose preoperative radiotherapy of primary inoperable oropharyngeal cancer

Despite the great progress made by tumor therapy in recent years, it has not yet been possible to obtain a decisive improvement in the five-year survival of about 20% and the five-year recurrence-free survival of about 30% of patients suffering from advanced T3 oropharynx carcinomas. A new way to improve the poor prognosis of these patients is only offered by the possibilities of modern radiotherapy with ultrahard X-radiation as well as by the progress of microsurgery. Up to now, the recurrence-free survival of our patient's group suffering from primarily inoperable T3 oropharynx carcinomas has reached 60% (increase of about 40%). This was achieved by preoperative high-dose irradiation and subsequent implantation of myocutaneous skin flaps with the vascular bundle supplying the flap with blood. As is shown by the communications of literature and our own experience, about 80% of all recurrences will appear within the first 24 months after the end of therapy. In our preoperatively high-dose irradiated group, the observation period is meanwhile 48 months, and the recurrence-free survival is still by 40% higher than that of the control groups. Although a new formation of local recurrences cannot be excluded for the further observation time and despite the small number of patients, the rate of recurrence-free patients suffering from tumors of stage T3N+ signifies a most promising therapeutic approach.     

Three-dimensional conformal radiotherapy in the treatment of prostate cancer in Australia and New Zealand: Report on a survey of radiotherapy centres and the proceedings of a consensus workshop

There is an increasing use of 3-D conformal radiotherapy (3DCRT) in the radiotherapeutic management of prostate cancer. The Faculty of Radiation Oncology Genito-Urinary Group carried out a survey of Australian and New Zealand radiotherapy centres in the preparation of a consensus workshop. Of the 19 centres that were represented, there were 24 radiation oncologists, 16 radiation therapists and 12 medical physicists. The survey collected demographic information and data on the practices undertaken at those centres when delivering curative radiotherapy in the treatment of prostate cancer. There was much variation in the delivery of treatment in the areas of patient set-up, contouring of target volumes and organs of interest during computer planning, the techniques and the dose constraints used in these techniques, the use of adjuvant androgen deprivation therapy and the quality assurance processes used in monitoring effects of treatment. This variability reflects the range of data in the published literature. Emerging trends of practices were also identified. This is a first report on a multi-disciplinary approach to the development of guidelines in 3DCRT of prostate cancer.     

原发性肝癌术前放疗及免疫治疗的研究进展

我国是肝癌大国, 近年来肝癌治疗方式越来越趋于综合性的治疗, 主要包括手术、消融、介入栓塞、放疗、化疗、靶向、免疫、肝移植等治疗。目前, 肝癌手术切除率低是影响预后主要因素之一, 肝癌术前新辅助治疗或转化治疗可以最大程度的提高手术切除率, 改善预后。随着放疗和免疫治疗在肝癌综合治疗中的快速发展, 肝癌术前放疗及免疫独特的治疗效果逐渐被证实改善患者预后。故本文通过搜索国内外相关文献报道, 综述了肝癌术前放疗及免疫治疗的研究进展。     

Use of digitally reconstructed radiographs in radiotherapy treatment planning and verification

The authors present 3 years of experience in using digitally reconstructed radiographs (DRR) for radiotherapy planning and verification. Comparison is made with simulation film (SF), to illustrate the advantages of DRR over SF. Emphasis is placed on using the appropriate equipment and applying the correct technique. A brief discourse on the principle of CT imaging is presented to illustrate the operation of CT software and optimization of image display for axial slices and DRR. Emphasis is placed on the application of clinical knowledge to enhance the usefulness, as well as the technical quality, of the DRR. Illustrative examples are given.     

Use of a programmable pocket calculator in radiotherapy treatment planning.

Software packages for a programmable pocket calculator have been developed for use in dosimetry. Using a field equation and a mathematical model of the beam profile, one can find the dose delivered to any point within the irradiated volume. Use of these programs for simple field calculations allows the radiologist to concentrate on more complex treatment plans.     

Postoperative radiotherapy and radiogold treatment of ovarian cancer

At the Allgemeine Krankenhaus St. Georg, Hamburg, 240 patients with ovarian carcinomas were submitted to an adjuvant treatment between 1961 and 1973. The external therapy with telecobalt or by an 18 MeV betatron was dosed from 3000 to 4000 rads. Most of the patients received an additional single intraperitoneal application of 150 mCi gold-198. The five-year survival rate of all patients was 45%, whereas it was 71% for stage I, 47% for stage II, 21% for stage III, and 4% for stage IV. In 3% out of all cases, surgical procedure was necessary because of complications. Today, an indication for intraperitoneal therapy by radioactive isotopes is only adopted in case of a ruptured malignant ovarian tumor.