Ciernik I F, Meier U, Lütolf U M
Department of Radiology, University Hospital, Zürich, Switzerland.
J Clin Oncol. 1994 Jul;12(7):1484-90. doi: 10.1200/JCO.1994.12.7.1484.
Stage III and stage IV thymomas with significant macroscopic infiltration to the neighboring structures are rarely completely resectable. It therefore remains unclear to what extent tumors must be surgically debulked to improve prognosis.
We reviewed the cases of 31 patients with incompletely resected invasive thymoma and residual macroscopic disease who were referred to postoperative irradiation. Survival and local tumor control were analyzed. All patients were treated between 1958 and 1990 with megavoltage irradiation at doses ranging from 42 to 66 Gy. The shortest follow-up time for living patients was more than 5 years.
The overall median 5-year survival rate was 45%. Eighteen stage III patients had a 5-year survival rate of 61% and a 10-year survival rate of 57%. Thirteen patients had stage IV disease and 5- and 10-year survival rates of 23% and 8%, respectively. Univariate and multivariate analyses confirmed a worse prognosis for stage IV disease. Epithelial or spindle-cell thymoma was associated with stage IV disease. Twenty-two percent of patients with stage III disease had epithelial or spindle-cell thymoma, versus 69% of patients with stage IV disease (P = .02 for univariate and P = .05 for multivariate analysis). Initial tumor diameter greater than 10 cm correlated with poor prognosis in the univariate analysis (P = .05). However, more importantly, debulking of tumor did not significantly improve outcome when compared with patients who received biopsy only. The median survival rate of patients with stage IVa disease did not differ from that of those with stage IVb disease. Mediastinal control was achieved in 23 patients (74%). Stage IV disease did not correlate with an increase in local treatment failure after irradiation, although epithelial or spindle-cell thymoma predisposed for local treatment failure (46% v 11%; P = .04 in univariate and P = .055 in multivariate analysis).
Tumor debulking leaving macroscopic residual thymoma, as opposed to biopsy alone, does not improve prognosis when followed by radiation. Radiation therapy for local tumor control is most effective in nonepithelial-predominant thymomas.
Ⅲ期和Ⅳ期胸腺瘤若对邻近结构存在明显的宏观浸润，则很少能完全切除。因此，尚不清楚肿瘤需在多大程度上进行手术减瘤才能改善预后。
我们回顾了31例浸润性胸腺瘤切除不完全且有肉眼可见残留病灶并接受术后放疗的患者病例。分析了生存率和局部肿瘤控制情况。所有患者在1958年至1990年间接受了42至66 Gy的兆伏级放疗。在世患者的最短随访时间超过5年。
总体5年生存率中位数为45%。18例Ⅲ期患者的5年生存率为61%，10年生存率为57%。13例患者为Ⅳ期疾病，5年和10年生存率分别为23%和8%。单因素和多因素分析均证实Ⅳ期疾病的预后较差。上皮型或梭形细胞胸腺瘤与Ⅳ期疾病相关。Ⅲ期疾病患者中有22%为上皮型或梭形细胞胸腺瘤，而Ⅳ期疾病患者中这一比例为69%（单因素分析P = 0.02，多因素分析P = 0.05）。单因素分析中，初始肿瘤直径大于10 cm与预后不良相关（P = 0.05）。然而，更重要的是，与仅接受活检的患者相比，肿瘤减瘤并未显著改善预后。Ⅳa期疾病患者的中位生存率与Ⅳb期疾病患者的中位生存率无差异。23例患者（74%）实现了纵隔控制。尽管上皮型或梭形细胞胸腺瘤易导致局部治疗失败（46%对11%；单因素分析P = 0.04，多因素分析P = 0.055），但Ⅳ期疾病与放疗后局部治疗失败的增加无关。
与单纯活检相比，术后放疗前行肿瘤减瘤但仍残留肉眼可见的胸腺瘤，并不能改善预后。局部肿瘤控制的放射治疗在非上皮为主型胸腺瘤中最有效。
