BackgroundRadiation therapy is the standard radical treatment for nasopharyngeal carcinoma (NPC) but also causes transient as well as long-term complications. Patients who develop severe radiation-induced brainstem injuries have a poor prognosis due to the lack of effective medical therapies. However, the relationship between brainstem injury and radiation volume dose is unknown. In this study, we found that radiation-induced brainstem injury was significantly associated with brainstem dose per unit volume.MethodsA retrospective analysis was performed on a consecutive cohort of 327 patients with NPC receiving IMRT from May 2005 to December 2014. Dose-volume data and long-term outcome were analyzed.ResultsThe median follow-up duration was 56 months (range, 3–141 months), and six with T4 and two with T3 patients had radiation-induced brainstem injuries. The 3-year and 5-year incidences were 2.2% and 2.8%, respectively. The latency period of brainstem injury ranged from 9 to 58 months, with a median period of 21 months. The Cox regression analysis showed that brainstem radiation toxicity was associated with the T4 stage, D2% of gross tumor volume of nasopharyngeal primary lesions and their direct extensions (GTVnx), Dmax (the maximum point dose), D1%, D0.1cc (the top dose delivered to a 0.1-ml volume), and D1cc (the top dose delivered to a 1-ml volume) of the brainstem (p < 0.05). Receiver operating characteristic (ROC) curves showed that GTVnx D2% and the Dmax, D1%, D0.1cc, and D1cc of the brainstem were significant predictors of brainstem injury. The area under the ROC curve for these five parameters was 0.724, 0.813, 0.818, 0.818, and 0.798, respectively (p < 0.001), and the cutoff points 77.26 Gy, 67.85 Gy, 60.13 Gy, 60.75 Gy, and 54.58 Gy, respectively, were deemed as the radiation dose limit.ConclusionsRadiotherapy-induced brainstem injury was uncommon in patients with NPC who received definitive IMRT. Multiple dose-volume data may be the dose tolerance of radiation-induced brainstem injury.

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Background To compared the patterns of lymph node recurrence after different prophylactic therapies to identify specific and effective target areas for prophylactic radiotherapy. Methods This retrospective study enrolled patients with recurrence from August 2011 to November 2015, who underwent different prophylactic therapies for esophageal squamous cell carcinoma after radical surgery previously. The patients were divided into unprotected, radiotherapy, chemotherapy, and radiochemotherapy groups. The recurrence patterns between these groups were compared. Results A total of 186 patients who met the above criteria were enrolled. The recurrence ratios of regional lymph nodes were 84.2%, 31.3%, 84.0%, and 48.0% in the unprotected, radiotherapy, chemotherapy, and radiochemotherapy groups, respectively. The recurrence ratio of regional lymph nodes in patients who received radiotherapy was significantly decreased ( P =0.009). The recurrence ratio of superior mediastinal lymph node was significantly lower than those of the chemotherapy and unprotected groups ( P =0.000). The recurrence ratios of the radiotherapy group with and without epigastrium coverage were 4/16 and 4/25, respectively, indicating no statistical difference with those of other groups ( P =0.259). The recurrence ratios with and without the coverage of anastomotic sites were 2/19 and 3/22, respectively, revealing no statistical difference with those of other groups ( P =0.712). Conclusion Prophylactic radiotherapy can significantly reduce the recurrence of regional lymph nodes, especially lymph node recurrence on the superior mediastinum.