Duffton Aileen, Sadozye Azmat, Devlin Lynsey, MacLeod Nicholas, Lamb Carolynn, Currie Suzanne, McLoone Philip, Sankaralingam Marimuthu, Foster John, Paterson Stephanie, Keatings Stefanie, Dodds David
1 Department of Clinical Oncology, Beatson West of Scotland Cancer Centre , Glasgow , UK.
2 Department of Clinical Physics and Bioengineering, Beatson West of Scotland Cancer Centre , Glasgow , UK.
Br J Radiol. 2018 Apr;91(1084):20170625. doi: 10.1259/bjr.20170625. Epub 2018 Feb 1.
To investigate feasibility and safety of stereotactic ablative radiotherapy in the management of prostate cancer while employing MR/CT fusion for delineation, fiducial marker seeds for positioning and Varian RapidArc with flattening filter free (FFF) delivery.
41 patients were treated for low-intermediate risk prostate cancer with initial prostate-specific antigen of ≤20 ng ml, Gleason score 6-7. Patients had MR/CT fusion for delineation of prostate ±seminal vesicles. CT/MR fusion images were used for delineation and planned using flattening filter free modality. Verification on treatment was cone beam CT imaging with fiducial markers for matching. Patients had Radiation Therapy Oncology Group scoring for genitourinary and gastointestinal symptoms at baseline, week 4, 10 and 18.
Clinically acceptable plans were achieved for all patients, all plans achieved the objective clinical target volume D99% ≥ 95%, and for planning target volume D95% ≥ 95%. Rectum dose constraints were met for 95.1% for V18 Gy ≤ 35%, 80% V28 Gy ≤ 10%. A total of 32 (78.0%) plans achieved all rectum dose constraints. Grade 1 acute genitourinary symptoms were 53.7% of patients at baseline, 90.2% [95% CI (76.8-97.3%)] (p = 0.0005) at treatment 5, falling to 78.0% (62.4-89.4%) at week 4, and 75.0% (58.8-87.3%) by week 10 and 52.5% (36.1-68.5%) (p = 1.00) at week 18. Acute gastrointestinal symptoms were 5% at baseline, 46.3% [95% CI (30.7-62.6%)] at treatment 5, week 4 43.9% [95% CI (28.5-60.3%)], week 10 25.0% (11.1-42.3%), and declined slightly by week 18 [-20.095% CI (12.7-41.2)] p = 0.039. Overall 75.6% (31/41) of patients experienced Grade 1-2 toxicity during or after treatment.
This planning and delivery technique is feasible, safe and efficient. A homogeneous dose can be delivered to prostate with confidence, whilst limiting high dose to nearby structures. The use of this technology can be applied safely within further randomized study protocols. Advances in knowledge: Multimodality imaging for delineation and linac-based image-guided RT with FFF for the treatment of prostate stereotactic ablative radiotherapy.
探讨立体定向消融放疗在前列腺癌治疗中的可行性和安全性，同时采用磁共振/计算机断层扫描（MR/CT）融合技术进行靶区勾画、使用基准标记种子进行定位以及瓦里安容积旋转调强放疗（Varian RapidArc）的无均整器（FFF）模式进行放疗。
41例低中危前列腺癌患者接受治疗，初始前列腺特异性抗原≤20 ng/ml， Gleason评分6 - 7分。患者采用MR/CT融合技术勾画前列腺±精囊。利用CT/MR融合图像进行靶区勾画，并采用无均整器模式进行计划制定。治疗验证采用锥形束CT成像及基准标记进行匹配。患者在基线、第4周、第10周和第18周接受放射治疗肿瘤学组（Radiation Therapy Oncology Group）关于泌尿生殖系统和胃肠道症状的评分。
所有患者均获得临床可接受的计划，所有计划均达到临床靶区体积D99%≥95%，计划靶区体积D95%≥95%。直肠剂量限制方面，95.1%的患者满足V18 Gy≤35%，80%的患者满足V28 Gy≤10%。共有32例（78.0%）计划满足所有直肠剂量限制。1级急性泌尿生殖系统症状在基线时为53.7%的患者，治疗第5周时为90.2%[95%可信区间（7,6.8 - 97.3%）]（p = 0.0005），第4周时降至7,8.0%（62.4 - 89.4%），第10周时为75.0%（58.8 - 87.3%），第18周时为52.5%（36.1 - 68.5%）（p = 1.00）。急性胃肠道症状在基线时为5%，治疗第5周时为46.3%[95%可信区间（30.7 - 62.6%）]，第4周时为43.9%[95%可信区间（28.5 - 60.3%）]，第10周时为25.0%（11.1 - 42.3%），第18周时略有下降[-20.095%可信区间（12.7 - 41.2）] p = 0.039。总体而言，75.6%（31/41）的患者在治疗期间或治疗后出现1 - 2级毒性反应。
这种计划制定和放疗技术是可行、安全且高效的。能够自信地将均匀剂量传递至前列腺，同时将高剂量限制在附近结构。该技术可在进一步的随机研究方案中安全应用。知识进展：多模态成像用于靶区勾画以及基于直线加速器的FFF图像引导放疗用于前列腺立体定向消融放疗。
