Deriving patient-specific planning target volume for partial bladder image guided radiation therapy

PurposeImage guided radiation therapy (IGRT) using bony anatomy for bladder cancer requires the use of large population-based planning target volume (PTV) margins to compensate for geometric uncertainties. This may result in a large volume of normal tissue being irradiated unnecessarily. Identification of the clinical target volume (CTV) is also a challenge during target delineation and treatment position verification. This study describes the use of lipiodol (Guerbet, US) and cone beam computed tomography (CBCT) in deriving patient-specific PTV (PS-PTV) for partial bladder IGRT.Methods and materialsTwelve patients underwent lipiodol injection into the bladder wall prior to radiation treatment. A PS-PTV was generated by the following: (1) Delineating partial bladder CTV (CTVpb) on 15 CBCTs; (2) registering the CBCTs with the planning CT image using lipiodol; (3) combining the 15 CTVpb to create an occupancy volume (OV); and (4) expanding the OV by 3 mm. Its efficacy in reducing irradiated volume and in providing coverage was assessed by comparing it with a 20-mm population-based PTV (popPTV) and using phase 2 CBCTs.ResultsThe median PS-PTV and popPTV (cm³) were 102 (range, 37-336) and 325 (range, 211-631), respectively. Median distance between the CTVpb and the PS-PTV edge (mm) were 6 superior, 6 right, 7 left, 7 anterior, 8 posterior, and 11 inferior. The absolute median reduction in the overlapping volume of rectum, small bowel, and large bowel were 0.3 cm³, 5.3 cm³, and 13.0 cm³, respectively. Despite large reductions in volume and margin compared with popPTV, PS-PTV achieved 100% target coverage.ConclusionsUsing lipiodol and CBCT to derive PS-PTV facilitated large reductions in the irradiated normal tissue volume without compromising target coverage.     

Late toxicity after intensity modulated and image guided radiation therapy for localized prostate cancer and post-prostatectomy patients

PurposeTo examine late gastrointestinal (GI) and genitourinary (GU) toxicity profiles of patients treated for prostate cancer either definitively or post-prostatectomy with both intensity modulated radiation therapy (IMRT) and image guided radiation therapy (IGRT).Methods and MaterialsA total of 333 patients treated definitively and 104 patients treated postoperatively with IMRT and varying IGRT techniques were retrospectively examined to evaluate GI and GU toxicity profiles > 1 year from treatment. Available dosimetric data were used for correlative analysis.ResultsThe median follow-up time for the definitive patients was 41 months and the median follow-up time for the post-prostatectomy patients was 33 months. No late grade 4 or 5 GI or GU toxicities were observed. For definitive patients, the rates of grade ≥ 2 GI and GU toxicity at 3 years were 4.9% and 4.5%, respectively. In the postoperative cohort the rate of grade > 2 GU toxicity was 11.6%, with no grade ≥ 2 GI toxicity. In the definitive cohort's Cox proportional hazards regression univariate analysis, use of anticoagulation was significantly associated with GI toxicity and age, bladder V50 and IGRT modality were associated with GU toxicity, and only age remained significant in the multivariate model. In univariate analysis for the postoperative cohort, no dosimetric value correlated with GU toxicity, nor did age or time from radical prostatectomy to radiation.ConclusionsIMRT with IGRT achieved low rates of GI and GU toxicity in the definitive and postoperative setting.     

图像引导放疗中图像配准算法性质的研究

目的 研究图像配准算法的基本行为,分析影响图像配准的各种因素.方法 先把待配准图像做一已知变换,然后基于自主开发的图像配准算法研究图像配准技术中感兴趣区域选择、优化目标函数时的初始位置选择、空间变换参数的空间耦合等对图像配准算法的影响.结果 感兴趣区域位置和区域大小选择对图像配准的结果影响非常明显,如果选择不当很容易导致配准失败;初始变换参数(优化的初始位置)选择恰当,能提高图像配准的准确度;参数空间的耦合会增加图像配准算法对感兴趣区域选择的敏感度.结论 图像引导放疗平台临床应用中非常有必要总结与肿瘤部位相关感兴趣区域的勾画策略(依赖具体图像配准软件平台),可以通过实现初始变换参数的自动优化选择来提高算法的抗干扰能力,并开发出针对不同图像特征(不同解剖部位)的具体配准算法.     

盆腔淋巴结转移性前列腺癌大分割调强放疗联合内分泌治疗疗效分析

目的:探讨盆腔淋巴结转移性前列腺癌大分割调强放疗联合内分泌治疗疗效及预后。方法:回顾分析中国医学科学院肿瘤医院2006—2018年收治的42例Ⅳ A期前列腺癌行大分割调强放疗联合内分泌治疗病例的临床资料。前列腺及精囊腺放疗总剂量67.5 Gy分25次,盆腔淋巴引流区处方剂量45～50 Gy,1.8～2.0 ...     

肺癌图像引导下大分割放射治疗技术初探

背景与目的图像引导放射治疗(IGRT)技术是近年来出现并应用于临床的精确放射治疗技术。本研究旨在探讨在肺癌放射治疗中应用呼吸门控及立体定向体架减少误差,提高治疗精度,从而提高单次剂量和总剂量。方法入组7例治疗后肺部复发或转移的肺癌患者,共计13个病灶。分割为7Gy,隔日照射,共7次。每次照射时利用容积CT技术修正三维方向误差。结果治疗前摆位时和计划时靶中心误差在左右、前后和头脚方向分别为0.30cm±0.14cm、0.22cm±0.15cm和0.28cm±0.21cm。调整后及治疗后误差减少。但三个方向在调整前、调整后及治疗后误差对比均无统计学差异。13个病灶中8个病灶达完全缓解,4个部分缓解,1个无变化。结论IGRT配合呼吸门控及立体定向体架技术对肺部肿瘤进行大分割放射治疗,能提高治疗剂量,缩短治疗时间,减少治疗副作用。     

Bisphosphonates and radiation therapy for palliation of metastatic bone disease

Radiotherapy is an established treatment for metastatic bone pain. It may be delivered as a localised low dose treatment for localised bone pain or systemically for more widespread symptoms using hemibody external beam radiotherapy or intravenous bone-seeking radioisotopes. Bisphosphonates have been shown to reduce morbidity from bone metastases when given to patients with asymptomatic disease from myeloma and primary breast and prostate cancers. They also reduce metastatic bone pain in these sites. In the absence of randomised data comparing radiotherapy with bisphosphonates in the same clinical setting, comparison of the response rates from individual trials of the two modalities suggests that the overall pain response in all tumour types from radiotherapy is around 80% compared to a similar rate in myeloma with bisphosphonates but only 40% in solid tumours. Optimal use of the two modalities requires further investigation but since they have different dose limiting toxicities their incorporation in a combined modality approach to metastatic bone pain is rational using the concepts of additive effect and spatial co-operation in which bisphosphonates provide background control alongside acute pain relief using radiotherapy. They are also an important alternative for bone pain where radiation tolerance has been reached or radiotherapy is not readily available.     

早期乳腺癌保乳术后图像引导放射治疗的临床价值

目的探讨早期乳腺癌保乳术后图像引导放射(IGRT)治疗的临床价值。方法选取2013年1月至2013年10月间确诊为早期乳腺癌并接受保乳术的患者60例。按照随机数字表法将60例患者分为调强放疗(IMRT)组和IGRT组,每组30例。评价两组靶区及正常组织所受照射剂量、急性毒性反应及乳房美容效果方面的差异。结果 IGRT组的适形指数(CI)和均匀指数(HI)均优于IMRT组,差异均有统计学意义(均P<0.05)。IGRT组正常组织所受照射剂量均低于IMRT组,差异有统计学意义(P<0.05)。两组皮肤毒性反应比较,差异无统计学意义(P>0.05),无Ⅱ^Ⅲ度急性皮肤毒性反应。放射治疗6个月后,两组患者乳房美容效果优良率均为100%。结论 IMRT和IGRT对早期乳腺癌保乳术后法放射治疗效果均较好,但IGRT具有更高的放射治疗精准度,能更好地减少正常组织的照射剂量,具有较高的临床应用价值。     

Systematic review of hypofractionated radiation therapy for prostate cancer

Prostate cancer is the second most prevalent solid tumor diagnosed in men in the United States and Western Europe. Conventionally fractionated external beam radiation therapy (1.8–2.0 Gy/fraction) is an established treatment modality for men in all disease risk groups. Emerging evidence from experimental and clinical studies suggests that the α/β ratio for prostate cancer may be as low as 1.5 Gy, which has prompted investigators around the world to explore moderately hypofractionated radiation therapy (2.1–3.5 Gy/fraction). We review the impetus behind moderate hypofractionation and the current clinical evidence supporting moderate hypofractionated radiation therapy for prostate cancer. Although hypofractionated radiation therapy has many theoretical advantages, there is no clear evidence from prospective, randomized, controlled trials showing that hypofractionated schedules have improved outcomes or lower toxicity than conventionally fractionated regimens. Currently, hypofractionated schedules should only be used in the context of clinical trials. High dose rate brachytherapy and stereotactic body radiation therapy (fraction size 3.5 Gy and greater) are alternative approaches to hypofractionation, but are beyond the scope of this report.     

Methods for image guided and intensity modulated radiation therapy in high-risk abdominal neuroblastoma

PurposeOur purpose was to determine methods for image guided intensity modulated radiation therapy (IMRT) in pediatric abdominal high-risk neuroblastoma and to quantify the degree of normal tissue dose reduction by using volumes compliant with International Commission on Radiation Units and Measurements (ICRU) Report 62.Methods and MaterialsEight consecutive children with high-risk abdominal neuroblastoma (median age, 2.5 years; range, 20 months-5 years) were treated with IMRT using volumes accounting for physiologic motion (IMRT_phys) and daily pretreatment cone beam computed tomographic localization. Comparative IMRT planning using conventional volumes (IMRT_std) provided quantification for dose reduction to normal tissues.ResultsThe IMRT_phys plan reduced the mean planning target volume from 668.8 ± 200.6 cc to 393.0 ± 132.5 cc (P < .001) and reduced mean body V50 from 1774.4 ± 383.9 cc to 1385.7 ± 365.7 cc (P < .001). The IMRT_phys plan reduced the percent mean dose to the ipsilateral kidney from 70.1% ± 4.3% to 66.0% ± 5.2% (P =.002); that to the contralateral kidney was reduced from 56.3% ± 7.0% to 40.7% ± 9.5% (P < .001), and that to the liver was reduced from 57.8% ± 16.0% to 22.1% ± 6.8% (P = .001).ConclusionsFor IMRT planning, ICRU 62-compliant volume definition with image guidance in the pediatric abdomen enables volumetric reduction of the planning target volume and reduces normal tissue dose. These methods provide a framework for more conformal treatment planning in the pediatric abdomen.     

Infection after prostatic transrectal fiducial marker implantation for image guided radiation therapy

PurposeThe aim of this retrospective study is to assess the risk of infection after transrectal ultrasound-guided fiducial marker insertion for image-guided radiotherapy of prostate cancer.Material and methodsBetween January 2016 and December 2020, 829 patients scheduled for intensity-modulated radiotherapy for prostate cancer had an intraprostatic fiducial marker transrectal implantation under ultrasound guidance by radiation-oncologists specialized in brachytherapy. Patients received standard oral prophylactic antibiotic with quinolone. If Gram negative bacteria resistant to quinolone were detected at the time of the prostate cancer biopsies, the antibioprophylaxis regimen was modified accordingly. The resistance to quinolone screening test was not repeated before fiducial marker insertion. Infectious complications were assessed with questionnaires at the time of CT-planning and medical record reviewed. Toxicity was evaluated according to CTCAE v5.0.ResultsThe median time between fiducial marker implantation and evaluation was 10 days (range: 0–165 days). Four patients (0.48%) developed urinary tract infection related to the procedure, mostly with Gram-negative bacteria resistant to quinolone (75%). Three had a grade 2 infection, and one patient experienced a grade 3 urosepsis. The quinolone-resistance status was known for two patients (one positive and one negative) and was unknown for the other two patients prior to fiducial marker implantation.ConclusionIntraprostatic transrectal fiducial marker implantation for image-guided radiotherapy is well tolerated with a low rate of infection. With such a low rate of infection, there is no need to repeat the search of Gram-negative bacteria resistant to quinolone before fiducial marker implantation if it was done at the time of prostate biopsies. Optimal antibioprophylaxis should be adapted to the known status of Gram-negative bacteria resistant to quinolone.     

Absence of toxicity with hypofractionated 3-dimensional radiation therapy for inoperable, early stage non-small cell lung cancer

Epidermal growth factor receptor (EGFR) is a member of the ErbB family of receptors. Its stimulation by endogenous ligands, EGF or transforming growth factor-alpha (TGF-α) results in activation of intracellular tyrosine kinase, therefore, cell cycle progression. High levels of EGFR expression are correlated with poor prognosis and resistance to radiation therapy in a variety of cancers, mostly in squamous-cell carcinoma of the head and neck (SCCHN). Blocking the EGFR by a monoclonal antibody results in inhibition of the stimulation of the receptor, therefore, in inhibition of cell proliferation, enhanced apoptosis, and reduced angiogenesis, invasiveness and metastases. The EGFR is a prime target for new anticancer therapy in SCCHN, and other agents in development include small molecular tyrosine kinase inhibitors and antisense therapies.     

Acute toxicity of image-guided hypofractionated proton therapy for localized prostate cancer

Background

Hypofractionated proton therapy (HFPT) is expected to become an effective treatment approach for localized prostate cancer (PCa). The purpose of this study was to evaluate differences in acute toxicity among patients with localized PCa treated with either conventional fractionated proton therapy (CFPT) or HFPT.

Methods

A total of 526 eligible patients treated with proton therapy between February 2013 and May 2016 in three phase II trials were analyzed. We prescribed 74 gray relative biological effectiveness equivalents [Gy (RBE)]/37 fractions for low-risk patients and 78 Gy (RBE)/39 fractions for intermediate- and high-risk patients in the CFPT group (n = 254) and 60 Gy (RBE)/20 fractions for low-risk and 63 Gy (RBE)/21 fractions for intermediate- and high-risk patients in the HFPT group (n = 272). Patients were evaluated for acute toxicity with the Common Terminology Criteria for Adverse Events, version 4.0, and urinary quality-of-life change using the International Prostate Symptom Score (IPSS).

Results

No grade ≥3 acute toxicity was observed in either group. Among acute genitourinary toxicities, grade 2 rates were 15% (n = 38) in CFPT and 5.9% (n = 16) in HFPT (P ≤ 0.001). The median baseline IPSSs of the CFPT and HFPT groups were 7 (0–29) and 6 (0–31), respectively (P = 0.70). One-month post-treatment scores were 9 (0–32) and 11 (0–32), respectively (P = 0.036), and 6-month post-treatment scores were 7 (0–30) and 7 (0–33), respectively (P = 0.88). There were no significant differences in acute gastrointestinal toxicity between the two groups.

Conclusion

Our results demonstrated the safety of HFPT for localized PCa patients in terms of acute toxicity.

     

Adjuvant hypofractionated radiation therapy for breast cancer after conserving surgery

AimsTo evaluate the incidence of locoregional recurrence (LRR) and the cosmetic results in a group of patients with breast cancer treated with a hypofractionated schedule of adjuvant radiotherapy after conservative surgery.Materials and methodsIn total, 539 patients with pTis–pT1–pT2 breast cancer underwent radiotherapy treatment after conservative surgery at the University of Florence and at the Pistoia Hospital. The dose delivered was 44 Gy (2.75 Gy daily fraction). The tumour bed boost (10 Gy) was given by electrons.ResultsAt the time of the analysis, 1.8% of patients (10/539) had breast relapse. No patients developed nodal recurrence (supraclavicular, axillary and internal mammary nodes). The 3- and 5-year actuarial rates for LRR were 1.2% (±0.5% standard error) and 2.1% (±0.6% standard error), respectively. Considering the late toxicity, we found that 412 (76.4%) patients had grade 0 or grade 1 late toxicity, 113 patients (20.9%) had grade 2 late toxicity and 14 patients (2.5%) had grade 3 late toxicity. No patients developed grade 4 toxicity.ConclusionThis type of approach resulted in an effective treatment in terms of local control in patients with negative or one to three positive axillary nodes and negative surgical margins. Patients treated with a hypofractionated schedule showed very good cosmesis.     

KV级CBCT图像引导胸部肿瘤治疗中三种配准方式的比较

目的:探讨胸部肿瘤IGRT治疗中不同图像配准方法对摆位误差的影响。方法:医科达Synergy IGRT直线加速器分别治疗胸部肿瘤患者20例,每次治疗前均行CBCT扫描,重建获得的CBCT图像与原计划CT图像进行配准,分析X、Y、Z轴方向的平移误差及旋转误差,比较骨性配准、灰度值配准及手动配准间的差异。结果:20例胸部肿瘤患者治疗前共行384次CBCT扫描。手动配准、骨性配准、灰度值配准在X轴的平移误差分别为(0.01±0.29)cm、(0.04±0.31)cm、(-0.02±0.28)cm,在Y轴的平移误差分别为(0.11±0.41)cm、(0.12±0.45)cm、(0.09±0.41)cm,在Z轴的平移误差分别为(-0.11±0.23)cm、(-0.05±0.22)cm、(-0.08±0.23)cm;X轴的旋转误差分别为(0.61±1.09)°、(0.34±1.44)°、(0.66±1.28)°,在Y轴的旋转误差分别为(0.06±0.83)°、(0.04±1.89)°、(0.16±1.6)°,在Z轴的旋转误差分别为(-0.17±1.45)°、(-0.19±1.53)°、(-0.13±1.45)°。结果显示手动配准、骨性配准和灰度值配准三种方式之间存在明显的差异。结论:胸部肿瘤患者行IGRT时,需要根据病变具体部位选择配准方式,建议自动配准后必要时结合手动微调,直到配准结果符合要求。     

Role of image guided radiation therapy in obese patients with gynecologic malignancies

PurposeWe investigated the effect of body mass index on setup errors by analyzing daily shifts required in treating patients undergoing image guided radiation therapy (IGRT) for gynecologic malignancies.Methods and MaterialsForty successive patients treated with daily kV-based IGRT for gynecologic malignancies between April 2009 and June 2012 were identified. Directional setup corrections were analyzed according to patient body mass index. Random and systematic setup errors were calculated. Image acquisition dose was estimated by performing ionization chamber measurements in a phantom.ResultsObese patients had larger random setup errors, particularly in the right-left (R-L) direction, with a setup error of 7.6 mm, versus 3.9 mm for nonobese patients. The range of individual patient random errors in the R-L direction was 1.5 to 7.6 mm among nonobese patients versus 2.0 to 17.0 mm among obese patients (P = .03, F-test). For obese patients, daily IGRT prevented treating outside the planning target volume in 33% of fractions, versus 16% in the nonobese group (P = .001). The mean total image acquisition dose from daily kV-IGRT was approximately 3 cGy, versus 150 cGy if daily megavoltage portal imaging were used to correct for erratic setup errors.ConclusionsDaily kV-based IGRT in obese patients allows for correction of erratic setup error and minimizes excess dose from portal imaging.     

Chest wall toxicity after hypofractionated proton beam therapy for liver malignancies

Purpose

Normal liver-sparing with proton beam therapy (PBT) allows for dose escalation in the treatment of liver malignancies, but it may result in high doses to the chest wall (CW). CW toxicity (CWT) data after PBT for liver malignancies are limited, with most published reports describing toxicity after a combination of hypofractionated proton and photon radiation therapy. We examined the incidence and associated factors for CWT after hypofractionated PBT for liver malignancies.

Nodal radiation therapy for metastatic melanoma

Purpose: The aim of this retrospective study was to review our experience of radiation therapy to regional nodes in patients with proven nodal metastases, with respect to regional control, late toxicity, and overall survival.

Methods and Materials: All patients with a histological diagnosis of malignant melanoma, with involvement of the regional nodes but without distant metastases, who commenced nodal irradiation between January 1985 and July 1995 at Peter MacCallum Cancer Institute were studied. The study population of 113 patients was divided into two categories: those with no residual macroscopic disease following nodal surgery (adjuvant group, 42 patients) and those who had no surgery (8) or had macroscopic residual disease following nodal surgery (63) (palliative group, 71 patients).

Results: In the adjuvant group at 5 years following commencement of nodal irradiation 26% were estimated to be failure-free. Of the 74% who had experienced treatment failure by 5 years, an estimated 20% failed first with nodal relapse, 52% with distant metastases, and 2% with both nodal relapse and distant metastases. The estimated 5-year overall survival for this group was 33%. In the palliative group 16 patients (23%) had an objective complete response. Altogether 48 patients (68%) had a symptomatic response. At 5 years the overall survival in this group was 8% and an estimated 4% were failure-free. Of the 96% who had failed by 5 years, 68% failed first in the regional nodes, 25% had distant metastases as the first failure, and 3% had both nodal relapse and distant metastases.

Conclusion: We recommend adjuvant postoperative radiation therapy for patients with proven nodal metastases and high risk of regional recurrence (multiple nodes, extracapsular extension, or recurrent nodal disease) in addition to adjuvant interferon.