Department of Pathology, Mount Sinai Hospital, New York, NY, USA.
Cancer Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
Mod Pathol. 2017 Oct;30(10):1433-1442. doi: 10.1038/modpathol.2017.54. Epub 2017 Jul 21.
Solitary fibrous tumors are an uncommon sarcoma type characterized by NAB2-STAT6 gene fusion. While solitary fibrous tumors metastasize in 5-25% of cases, it has historically been challenging to determine which specific tumor and patient characteristics predict aggressive behavior. We previously reported on a novel risk stratification scheme for solitary fibrous tumors incorporating patient age, tumor size, and mitotic activity to predict risk of metastasis. Herein we validate this risk stratification scheme in an independent, lower-risk population of 79 patients with primary non-meningeal solitary fibrous tumors, and propose incorporating tumor necrosis as a fourth variable to further improve the risk score. Fifty-seven percent of cases were considered low risk, 29% intermediate risk, and 14% high risk for metastasis. Of 50 patients with sufficient clinical follow-up data, no metastases developed in the low-risk patients (n=23), while there was a 7% 10-year metastatic risk in the intermediate risk group (n=17), and a 49% 5-year metastatic risk for the high-risk patients (n=10). When tumor necrosis was added as a fourth variable to the model, predictive power was enhanced. Under the revised stratification, the proportion of tumors identified as low risk increased to 66%, with no metastasis at 10 years, intermediate risk cases comprised 24% with 10% risk of metastasis at 10 years, and high risk comprised 10% of cases with 73% risk of metastasis at 5 years. In Kaplan-Meier analysis, this fourth-variable stratification provided significant discrimination between the risk groups (P=0.0005). These findings confirmed the clinical utility of our previously published risk stratification model and support the inclusion of necrosis as a fourth variable in the model.
孤立性纤维瘤是一种罕见的肉瘤类型，其特征是存在 NAB2-STAT6 基因融合。虽然孤立性纤维瘤在 5-25%的病例中发生转移，但历史上一直难以确定哪些特定的肿瘤和患者特征预测侵袭性行为。我们之前报道了一种新的孤立性纤维瘤风险分层方案，该方案纳入了患者年龄、肿瘤大小和有丝分裂活性，以预测转移风险。在此，我们在一个独立的、风险较低的 79 例原发性非脑膜孤立性纤维瘤患者群体中验证了该风险分层方案，并提出将肿瘤坏死作为第四个变量纳入，以进一步提高风险评分。79 例患者中，57%被认为是低危，29%为中危，14%为高危。在有足够临床随访数据的 50 例患者中，低危患者（n=23）无一例发生转移，中危患者（n=17）10 年转移风险为 7%，高危患者（n=10）5 年转移风险为 49%。当肿瘤坏死作为第四个变量加入模型时，预测能力得到增强。在修订后的分层中，被确定为低危的肿瘤比例增加到 66%，10 年内无转移；中危病例占 24%，10 年内转移风险为 10%；高危病例占 10%，5 年内转移风险为 73%。在 Kaplan-Meier 分析中，这种四变量分层法在风险组之间提供了显著的区分（P=0.0005）。这些发现证实了我们之前发表的风险分层模型的临床实用性，并支持将坏死作为模型的第四个变量纳入。
