Eldredge Harriet B, Studenski Matthew, Keith Scott W, Trabulsi Edouard, Lallas Costas D, Gomella Leonard G, Dicker Adam P, Showalter Timothy N
Department of Radiation Oncology Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
J Med Imaging Radiat Oncol. 2011 Oct;55(5):507-15. doi: 10.1111/j.1754-9485.2011.02305.x.
The purpose of this study is to assess the acute and late genitourinary (GU) and gastrointestinal (GI) toxicities of cone-beam computed tomography (CBCT) guided conformal adjuvant and salvage post-prostatectomy radiotherapy (RT) compared with RT with port films.
Sixty-eight patients (group 1) were treated with RT following radical prostatectomy (RP) using CBCT-guided conformal RT to a median dose of 68.4Gy. CBCT images were acquired three to five times weekly and were automatically co-registered to a reference CT. A comparative group (group 2) included 150 patients who received post-RP RT with weekly port films to a median dose of 64.8Gy. GU and GI toxicities were graded in both the acute and late settings using Radiation Therapy Oncology Group criteria. Associations between toxicity and study variables were evaluated by odds ratios (ORs) estimated by logistic regression.
Grades 2 and 3 acute GU toxicity were experienced by 13% (n=9) and 2% (n=1) of patients in group 1, respectively, while 13% (n=19) had grade 2 acute GU toxicity in the control group (group 2). Grade 2 acute GI toxicity was experienced by 13% (n=9) and 15% (n=23) in groups 1 and 2, respectively. Acute GU (P=0.67) and GI (P =0.84) toxicities were not significantly different between the two groups. There were no associations detected between CBCT and acute GI toxicity (OR 0.76, P=0.57) or acute GU (OR 1.16, P=0.75). Increased odds of acute GU toxicity were observed for doses>68.4Gy (OR 12.81, P=0.04), which were only delivered in the CBCT group. CBCT mean variations (standard deviation) for 1053 fractions were 2.8mm (2.8), 2.0mm (2.4) and 3.1mm (2.9) in the left-to-right, anterior-to-posterior (AP) and superior-to-inferior (SI) axes, respectively. Corrective shifts for variance≥5mm were required for 15%, 6% and 19% of fractions in the left-to-right, anterior-to-posterior and superior-to-inferior axes, respectively.
Rates of acute toxicity with CBCT-guided post-RP RT to 68.4Gy were similar to treatment to 64.8Gy without image-guidance RT. Acceptable early toxicity profiles suggest that CBCT is a reasonable strategy for image guidance, but the value of CBCT must be weighed against potential increased risk of secondary cancers due to increased radiation exposure.
本研究旨在评估与使用射野片的放射治疗（RT）相比，锥形束计算机断层扫描（CBCT）引导的适形辅助及挽救性前列腺切除术后放疗（RT）的急性和晚期泌尿生殖系统（GU）及胃肠道（GI）毒性。
68例患者（第1组）在根治性前列腺切除术（RP）后接受CBCT引导的适形RT，中位剂量为68.4Gy。每周获取3至5次CBCT图像，并自动与参考CT进行配准。一个比较组（第2组）包括150例接受RP后RT的患者，使用每周射野片，中位剂量为64.8Gy。使用放射肿瘤学组标准对急性和晚期的GU和GI毒性进行分级。通过逻辑回归估计的优势比（OR）评估毒性与研究变量之间的关联。
第1组分别有13%（n = 9）和2%（n = 1）的患者经历2级和3级急性GU毒性，而对照组（第2组）有13%（n = 19）的患者有2级急性GU毒性。第1组和第2组分别有13%（n = 9）和15%（n = 23）的患者经历2级急性GI毒性。两组之间的急性GU（P = 0.67）和GI（P = 0.84）毒性无显著差异。未检测到CBCT与急性GI毒性（OR 0.76，P = 0.57）或急性GU（OR 1.16，P = 0.75）之间的关联。对于剂量>68.4Gy，观察到急性GU毒性的优势增加（OR 12.81，P = 0.04），这仅在CBCT组中出现。1053个分次的CBCT平均偏差（标准差）在左右、前后（AP）和上下（SI）轴上分别为2.8mm（2.8）、2.0mm（2.4）和3.1mm（2.9）。左右、前后和上下轴上分别有15%、6%和19%的分次需要进行方差≥5mm的校正移位。
CBCT引导的RP后RT至68.4Gy的急性毒性发生率与未进行图像引导RT至64.8Gy的治疗相似。可接受的早期毒性特征表明CBCT是一种合理的图像引导策略，但必须权衡CBCT的价值与因辐射暴露增加导致继发癌症的潜在风险增加。
