Department of Radiation Oncology Section 3994, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.
Strahlenther Onkol. 2012 Aug;188(8):671-6. doi: 10.1007/s00066-012-0127-y. Epub 2012 May 13.
Methods to estimate the likely origin of recurrences after radiation therapy for head and neck squamous cell carcinoma are compared.
A total of 25 patients meeting the following inclusion criteria were randomly selected: curatively intended intensity-modulated radiotherapy planned on a positron emission tomography-computed tomography (PET/CT) scan during the period 2005-2009; squamous cell carcinoma in the oral cavity, pharynx or larynx; complete clinical response followed by locoregional recurrence; and a CT scan at recurrence before any salvage therapy. Exclusion criteria were previous cancer in the area, surgery prior to radiotherapy, or a synchronous cancer. Three methods of estimating focal points of recurrence origin and two volume overlap methods assigning the recurrences to the most central target volumes encompassing at least 50% or 95% of the recurrence volumes were tested. Treatment planning and recurrence scans were rigid and deformable co-registered in order to transfer focal points to the treatment planning scan. Double determinations of all volumes, points, and co-registrations were made.
The volume overlap methods assigned the recurrences to significantly more peripheral target volumes than focal methods (p < 0.0001 for all comparisons of 95% overlap vs. focal methods, p < 0.028 for all comparisons of 50% overlap vs. focal methods). Repeated registrations of the same point had higher reproducibility with deformable registration than with rigid registration (median distance 0.31 vs. 0.35 cm, p = 0.015). No significant differences were observed among the focal methods.
Significant differences between methods were found which may affect strategies to improve radiotherapy based on pattern of failure analyses.
比较用于估计头颈部鳞状细胞癌放射治疗后复发的可能起源的方法。
共随机选择了 25 名符合以下纳入标准的患者：2005 年至 2009 年期间在正电子发射断层扫描计算机断层扫描（PET/CT）扫描上计划进行有治愈意图的强度调制放射治疗；口腔、咽或喉的鳞状细胞癌；完全临床缓解后局部区域复发；以及在任何挽救性治疗之前在复发时进行 CT 扫描。排除标准为该区域先前有癌症、放射治疗前手术或同时性癌症。测试了估计复发起源焦点的三种方法和两种体积重叠方法，将复发分配给至少包含 50%或 95%复发体积的最中央靶体积。为了将焦点转移到治疗计划扫描，对治疗计划和复发扫描进行了刚性和可变形的配准。对所有体积、点和配准进行了两次测定。
与焦点方法相比，体积重叠方法将复发分配到明显更外围的靶体积（所有 95%重叠与焦点方法的比较，p<0.0001；所有 50%重叠与焦点方法的比较，p<0.028）。同一点的重复配准使用变形配准比刚性配准具有更高的可重复性（中位数距离 0.31 与 0.35 cm，p=0.015）。焦点方法之间没有观察到显著差异。
发现了方法之间的显著差异，这可能会影响基于失败模式分析的放射治疗策略。
