Estimating PTV Margins in Head and Neck Stereotactic Ablative Radiation Therapy (SABR) Through Target Site Analysis of Positioning and Intrafractional Accuracy.
通过定位和内照射精度的靶位点分析，估计头颈部立体定向消融放射治疗 (SABR) 中的PTV边缘。
- 作者列表："Mesko S","Wang H","Tung S","Wang C","Pasalic D","Chapman BV","Moreno AC","Reddy JP","Garden AS","Rosenthal DI","Gunn GB","Frank SJ","Fuller CD","Morrison W","Phan J
PURPOSE:Recurrent or previously irradiated head and neck cancers (HNC) are therapeutically challenging and may benefit from high-dose, highly accurate radiation techniques, such as stereotactic ablative radiation therapy (SABR). Here, we compare set-up and positioning accuracy across HNC subsites to further optimize the treatment process and planning target volume (PTV) margin recommendations for head and neck SABR. METHODS AND MATERIALS:We prospectively collected data on 405 treatment fractions across 79 patients treated with SABR for recurrent/previously irradiated HNC. First, interfractional error was determined by comparing ExacTrac x-ray to the treatment plan. Patients were then shifted and residual error was measured with repeat x-ray. Next, cone beam computed tomography (CBCT) was compared with ExacTrac for positioning agreement, and final shifts were applied. Lastly, intrafractional error was measured with x-ray before each arc. Results were stratified by treatment site into skull base, neck/parotid, and mucosal. RESULTS:Most patients (66.7%) were treated to 45 Gy in 5 fractions (range, 21-47.5 Gy in 3-5 fractions). The initial mean ± standard deviation interfractional errors were -0.2 ± 1.4 mm (anteroposterior), 0.2 ± 1.8 mm (craniocaudal), and -0.1 ± 1.7 mm (left-right). Interfractional 3-dimensional vector error was 2.48 ± 1.44, with skull base significantly lower than other sites (2.22 vs 2.77; P = .0016). All interfractional errors were corrected to within 1.3 mm and 1.8°. CBCT agreed with ExacTrac to within 3.6 mm and 3.4°. CBCT disagreements and intrafractional errors of >1 mm or >1° occurred at significantly lower rates in skull base sites (CBCT: 16.4% vs 50.0% neck, 52.0% mucosal, P < .0001; intrafractional: 22.0% vs 48.7% all others, P < .0001). Final PTVs were 1.5 mm (skull base), 2.0 mm (neck/parotid), and 1.8 mm (mucosal). CONCLUSIONS:Head and neck SABR PTV margins should be optimized by target site. PTV margins of 1.5 to 2 mm may be sufficient in the skull base, whereas 2 to 2.5 mm may be necessary for neck and mucosal targets. When using ExacTrac, skull base sites show significantly fewer uncertainties throughout the treatment process, but neck/mucosal targets may require the addition of CBCT to account for positioning errors and internal organ motion.
目的: 复发性或既往照射过的头颈部肿瘤 (HNC) 具有治疗挑战性，可能受益于高剂量、高精度的放射技术，如立体定向消融放射治疗 (SABR)。在此，我们比较了HNC各亚位点的设置和定位精度，以进一步优化头颈部SABR的治疗过程和计划目标体积 (PTV) 边缘建议。 方法和材料: 我们前瞻性收集了 79 例接受SABR治疗的复发性/既往照射HNC患者的 405 个治疗组分的数据。首先，通过比较ExacTrac x射线与治疗计划确定分数间误差。然后对患者进行移位，用重复x线测量残余误差。接下来，将锥形束计算机断层扫描 (CBCT) 与ExacTrac进行定位一致性比较，并应用最终移位。最后，在每条圆弧前用x射线测量运动内误差。结果按治疗部位分为颅底、颈部/腮腺和粘膜。 结果: 大多数患者 (66.7%) 接受了 5 次 45 Gy的治疗 (3-5 次 21-47.5 Gy)。初始平均 ± 标准差分次误差为-0.2 ± 1.4毫米 (前后位) 、 0.2 ± 1.8毫米 (颅侧) 和-0.1 ± 1.7毫米 (左右)。分数阶间 3 维向量误差为 2.48 ± 1.44，颅底明显低于其他部位 (2.22 vs 2.77; P = .0016)。所有分数间误差均校正到 1.3毫米和 1.8 ° 以内。CBCT同意ExacTrac在 3.6毫米和 3.4 ° 内。在颅底部位，CBCT分歧和> 1毫米或> 1 ° 的动作内错误发生率显著较低 (CBCT: 16.4% vs 50.0% 颈部，52.0% 粘膜，P <。0001; 牵引力内: 22.0% vs 48.7% 所有其他，P <.0001)。最终PTVs为 1.5毫米 (颅底) 、 2.0毫米 (颈部/腮腺) 和 1.8毫米 (粘膜)。 结论: 头颈部SABR PTV边缘应按靶位点优化。1.5 至 2毫米的PTV边缘在颅底可能足够，而 2 至 2.5毫米可能是颈部和粘膜靶点所必需的。当使用ExacTrac时，颅底部位在整个治疗过程中表现出明显较少的不确定性，但颈部/粘膜靶点可能需要添加CBCT来解释定位错误和内部器官运动。
METHODS:OBJECTIVE:Large inoperable sacral chordomas show unsatisfactory local control rates even when treated with high dose proton therapy (PT). The aim of this study is assessing feasibility and reporting early results of patients treated with PT and concomitant hyperthermia (HT). METHODS: :Patients had histologically proven unresectable sacral chordomas and received 70 Gy (relative biological effectiveness) in 2.5 Gy fractions with concomitant weekly HT. Toxicity was assessed according to CTCAE_v4. A volumetric tumor response analysis was performed. RESULTS: :Five patients were treated with the combined approach. Median baseline tumor volume was 735 cc (range, 369-1142). All patients completed PT and received a median of 5 HT sessions (range, 2-6). Median follow-up was 18 months (range, 9-26). The volumetric analysis showed an objective response of all tumors (median shrinkage 46%; range, 9-72). All patients experienced acute Grade 2-3 local pain. One patient presented with a late Grade 3 iliac fracture. CONCLUSION:Combining PT and HT in large inoperable sacral chordomas is feasible and causes acceptable toxicity. Volumetric analysis shows promising early results, warranting confirmation in the framework of a prospective trial. ADVANCES IN KNOWLEDGE: :This is an encouraging first report of the feasibility and early results of concomitant HT and PT in treating inoperable sacral chordoma.
METHODS:BACKGROUND:National guidelines recommend screening and treatment for cancer-related bone disease and continued monitoring of bone-modifying agents. It is unclear whether a standardized screening tool is utilized to identify eligible patients and ensure appropriate supportive care is implemented. The purpose of this study was to evaluate current prescribing practices and optimize management of bone-modifying agents. METHODS:A retrospective chart review was performed to identify patients who received hormone deprivation therapy or had bone metastases through Hematology/Oncology or Urology clinics from 1 November 2016 to 31 October 2017. The primary endpoints of this study were the incidence of completed baseline dual-energy X-ray absorptiometry (DEXA) scan for patients on hormone deprivation therapy and percent of patients started on a bone-modifying agent for the prevention of skeletal-related events secondary to bone metastasis. Secondary endpoints included percent of patients with dental examinations prior to initiation, adequate calcium and vitamin D supplementation, incidence of osteonecrosis of the jaw or flu-like symptoms and education, and percent of bisphosphonate doses appropriately adjusted based on renal function. RESULTS:A total of 375 patients were assessed for baseline DEXA scans and bone-modifying therapy. Of the 226 patients on hormone deprivation therapy, 111 (49%) patients were appropriately screened with a DEXA scan prior to initiation of hormone deprivation therapy. Among the 149 patients with bone metastases, only 94 (63.1%) patients were started on a bone-modifying agent. CONCLUSIONS:Opportunities have been identified to optimize management of patients with cancer-related bone disease. Implementation of standardized tools may increase the rate of appropriate screening and initiation of bone-modifying therapy when warranted.
METHODS:PURPOSE:Low skeletal muscle mass has been associated with poor prognosis in patients with advanced lung cancer. However, little is known about the relationship between skeletal muscle mass and overall survival in patients with bone metastases from lung cancer. The objective of the present study was to evaluate the prognostic value of low trunk muscle mass in predicting overall survival in these patients. METHODS:The data from 198 patients who were diagnosed with bone metastases from lung cancer from April 2009 to May 2017 were retrospectively reviewed. The areas of the psoas and paravertebral muscles were measured at the level of the third lumbar vertebra on computed tomography scans taken at the time nearest to the diagnosis of bone metastasis. Muscle area was evaluated for male and female cohorts separately using different cutoff points. Cox proportional hazards analysis was performed to evaluate the factors independently associated with overall survival. RESULTS:The overall survival of patients in the lowest quartile for psoas muscle area or paravertebral muscle area was significantly shorter than that of patients above the 25th percentile for muscle area (p < 0.001). Multivariate analyses showed that paravertebral muscle mass (hazard ratio, 1.73; 95% confidence interval, 1.17-2.56; p = 0.006), epidermal growth factor receptor-targeted therapy, and performance status were independent prognostic factors. CONCLUSIONS:Low paravertebral muscle mass was associated with shorter survival, independently of known prognostic factors.