Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, The Netherlands.
Radiother Oncol. 2013 Jun;107(3):282-7. doi: 10.1016/j.radonc.2013.05.004. Epub 2013 Jun 3.
To report on the potential benefits of swallowing-sparing intensity-modulated radiation therapy (SW-IMRT) in the first 100 SW-IMRT treated patients, as well as on the factors that influence the potential benefit of SW-IMRT relative to standard parotid sparing (ST)-IMRT.
One hundred consecutive head and neck cancer patients, scheduled for primary radiotherapy, were included in this prospective cohort study. For each patient, ST-IMRT and SW-IMRT treatment plans were created. All patients were eventually treated with SW-IMRT. Objectives for SW-IMRT were identical to those with ST-IMRT, with additional objectives to spare the swallowing organs at risk (SWOARs). After 20 patients, interim results were evaluated by a multidisciplinary committee.
The mean gain of SW-IMRT relative to ST-IMRT in the first 20 patients was less than expected based on our previous planning comparative study. A critical review of all plans revealed that the results with SW-IMRT could be improved by: (1) gaining experience and attempting to reduce SWOAR dose as much as possible; (2) accepting a moderate shift of dose to unspecified tissues; (3) maximizing SWOAR sparing while keeping PTV coverage exactly according to protocol. In the additional 80 patients, the mean dose to the various SWOARs was further reduced significantly compared to ST-IMRT. Dose reductions with SW-IMRT were largest for patients who received neck irradiation, had a tumour located in the larynx, oropharynx, nasopharynx or oral cavity, and had <75% overlap between SWOARs and PTVs. The mean absolute reduction in predicted physician-rated RTOG grade 2-4 swallowing dysfunction for patients numbered 21-100 was 6.1%, ranging from 0.0% to 17.2%.
The benefit of SW-IMRT depends significantly on neck radiotherapy, tumour site and the amount of overlap between SWOARs and PTVs. Optimal clinical introduction requires a detailed evaluation and comparison between the standard (ST-IMRT) and new technique (SW-IMRT) in order to fully exploit the potential benefits.
报告 100 例接受吞咽保护调强放疗（SW-IMRT）的患者中 SW-IMRT 的潜在益处，并报告影响 SW-IMRT 相对于标准腮腺保护（ST-IMRT）潜在益处的因素。
本前瞻性队列研究纳入了 100 例计划行根治性放疗的头颈部癌症患者。为每位患者制定了 ST-IMRT 和 SW-IMRT 治疗计划。所有患者最终均接受 SW-IMRT 治疗。SW-IMRT 的目标与 ST-IMRT 相同，另外的目标是保护吞咽危险器官（SWOARs）。20 例患者后，由多学科委员会对中期结果进行评估。
前 20 例患者中，SW-IMRT 相对于 ST-IMRT 的平均增益低于我们之前的计划比较研究预期。对所有计划进行了严格审查，结果表明可以通过以下方法提高 SW-IMRT 的效果：（1）积累经验，尽可能减少 SWOAR 剂量；（2）接受将剂量适度转移至未指定组织；（3）在满足方案要求的情况下，最大程度地保护 SWOAR 同时保持 PTV 覆盖。在另外 80 例患者中，与 ST-IMRT 相比，各种 SWOAR 的平均剂量进一步显著降低。SW-IMRT 剂量降低幅度最大的是接受颈部放疗、肿瘤位于喉、口咽、鼻咽或口腔、SWOAR 与 PTV 重叠度<75%的患者。第 21-100 例患者预计 RTOG 2-4 级吞咽功能障碍的平均绝对减少量为 6.1%，范围为 0.0%-17.2%。
SW-IMRT 的获益显著取决于颈部放疗、肿瘤部位以及 SWOAR 与 PTV 之间的重叠程度。为了充分利用潜在益处，需要对标准（ST-IMRT）和新技术（SW-IMRT）进行详细评估和比较，然后再进行优化临床引入。
