Haniuda M, Miyazawa M, Yoshida K, Oguchi M, Sakai F, Izuno I, Sone S
Department of Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
Ann Surg. 1996 Aug;224(2):219-24. doi: 10.1097/00000658-199608000-00016.
The authors determined the effect of postoperative mediastinal irradiation in preventing local and pleural recurrence of thymoma.
The role of mediastinal irradiation after incomplete resection or biopsy of an invasive thymoma is well established. However, routine use of adjuvant mediastinal irradiation for patients with thymoma after complete resection remains controversial.
During the 19-year period from 1973 to 1992, operations were performed on 89 patients with thymoma. Of these 89 patients, 80 patients who underwent gross complete tumor resection including adjacent tissues that appeared to be invaded by tumor were selected for this study. The effects of postoperative mediastinal irradiation on the recurrence rate of thymoma were analyzed according to histologic type, clinical stage, and whether adhesions to or invasion of the pleura or pericardium were present.
Recurrence of thymoma was observed in 13 of 80 (16.3%) patients. No recurrence was observed in 23 patients with noninvasive thymoma. In patients with invasive thymoma whose tumor was macroscopically adherent to the pleura but not microscopically invasive (p1), recurrence was observed in 4 of 11 patients (36.4%) when mediastinal irradiation was not performed, but in none of 10 patients who received mediastinal irradiation. However, in patients with microscopic pleural invasion (p2), a high recurrence rate was observed with mediastinal irradiation (40%, 6/15 patients) or without mediastinal irradiation (30%, 3/10 patients). Postoperative mediastinal irradiation for patients with microscopical invasion to pericardium (c2) did not decrease the recurrence rate. Analysis of the mode of recurrence showed that mediastinal irradiation may have been effective in preventing local recurrence, but it did not control the pleural dissemination that was observed in 12 of 13 recurrent cases.
Mediastinal irradiation is not necessary for patients with noninvasive thymoma. In patients with invasive thymoma, postoperative mediastinal irradiation is effective in preventing recurrence in patients with p1 thymoma, but not in patients with p2 or c2 tumors. Further adjuvant therapy should be performed to supplement mediastinal irradiation in patients with p2 or c2 thymoma, even after complete resection.
作者确定术后纵隔放疗在预防胸腺瘤局部和胸膜复发中的作用。
侵袭性胸腺瘤不完全切除或活检后纵隔放疗的作用已得到充分证实。然而，对于完全切除后的胸腺瘤患者常规使用辅助性纵隔放疗仍存在争议。
在1973年至1992年的19年期间，对89例胸腺瘤患者进行了手术。在这89例患者中，选取80例行大体肿瘤完全切除，包括切除似乎被肿瘤侵犯的相邻组织的患者进行本研究。根据组织学类型、临床分期以及是否存在胸膜或心包粘连或侵犯情况，分析术后纵隔放疗对胸腺瘤复发率的影响。
80例患者中有13例（16.3%）出现胸腺瘤复发。23例非侵袭性胸腺瘤患者未观察到复发。在肿瘤肉眼上与胸膜粘连但镜下无侵袭（p1）的侵袭性胸腺瘤患者中，未进行纵隔放疗的11例患者中有4例（36.4%）复发，而接受纵隔放疗的10例患者均未复发。然而，在镜下胸膜侵袭（p2）的患者中，无论是否进行纵隔放疗，复发率都很高（纵隔放疗组为40%，15例患者中有6例；未放疗组为30%，10例患者中有3例）。对心包有镜下侵袭（c2）的患者进行术后纵隔放疗并未降低复发率。复发模式分析表明，纵隔放疗可能对预防局部复发有效，但未能控制13例复发病例中12例出现的胸膜播散。
非侵袭性胸腺瘤患者无需进行纵隔放疗。对于侵袭性胸腺瘤患者，术后纵隔放疗对p1期胸腺瘤患者预防复发有效，但对p2期或c2期肿瘤患者无效。对于p2期或c2期胸腺瘤患者，即使在完全切除后，也应进行进一步的辅助治疗以补充纵隔放疗。
