Background The rarity and complexity of soft tissue sarcoma (STS) make it a challenge to determine the incidence, survival, and metastasis rates. In addition, the clinicopathological risk factors for lymph node metastasis have rarely been reported. Methods Data on patients diagnosed with STS in the SEER database from 2000 to 2018 were extracted by SEER*Stat 8.3.9.1, and the incidence trend was calculated by Joinpoint 4.9 software. The KM method was used to calculate the survival curve, and the log-rank method was used to compare differences in the survival curves. The clinicopathological risk factors for lymph node metastasis were screened by logistic regression. Results Among the 35987 patients, 4299 patients (11.9%) had distant metastasis. The overall lymph node metastasis rate was 6.02%, which included patients suffering from both lymph node and distant metastasis. Considering that some lymph node metastases might be accompanying events of distant metastasis, the rate of only lymph node metastasis in STS patients decreased to 3.42% after excluding patients with distant metastasis. Patients with only lymph node metastases (N1/2M0) had a significantly worse prognosis than those without metastases (N0M0) but a better prognosis than those with only distant metastases (N0M1) (p<0.0001). In the multivariate logistic analysis, STS patients with larger tumors located in the head and neck, viscera, retroperitoneum, and certain specific pathological subtypes (compared with the liposarcoma), such as undifferentiated pleomorphic sarcoma, rhabdomyosarcoma, endometrial stromal sarcoma, gastrointestinal stromal tumor, synovial sarcoma, and angiosarcoma, had a higher risk of lymph node metastasis. Conclusions Lymph node metastasis is rare in STS, and the metastasis rate is significantly different among the different pathological types. Tumor size, location, and pathological subtype are significantly associated with the risk of lymph node metastasis. The overall survival of patients with lymph node metastasis is better than that of patients with distant metastasis, which suggests a more precise prognosis evaluation should be performed in these AJCC stage IV STS patients.

中文翻译：

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泛软组织肉瘤的发病率、生存率和转移率分析：一项以人群为基础的研究，重点关注远处转移和淋巴结转移。

背景 软组织肉瘤 (STS) 的罕见性和复杂性使得确定发病率、存活率和转移率成为一项挑战。此外，关于淋巴结转移的临床病理危险因素也鲜有报道。方法采用SEER*Stat 8.3.9.1提取SEER数据库2000-2018年诊断为STS的患者资料，采用Joinpoint 4.9软件计算发病趋势。采用KM法计算生存曲线，采用log-rank法比较生存曲线的差异。采用logistic回归筛选淋巴结转移的临床病理危险因素。结果 35987例患者中，4299例（11.9%）发生远处转移。总淋巴结转移率为6.02%，其中包括患有淋巴结和远处转移的患者。考虑到部分淋巴结转移可能伴有远处转移事件，排除远处转移患者后，STS患者仅淋巴结转移率下降至3.42%。仅有淋巴结转移的患者 (N1/2M0) 的预后明显比无转移的患者 (N0M0) 差，但比仅有远处转移的患者 (N0M1) 预后好 (p<0.0001)。在多因素logistic分析中，较大肿瘤位于头颈部、内脏、腹膜后以及某些特定病理亚型（与脂肪肉瘤相比）的STS患者，如未分化多形性肉瘤、横纹肌肉瘤、子宫内膜间质肉瘤、胃肠道间质瘤、滑膜肉瘤，和血管肉瘤，淋巴结转移的风险更高。结论 STS淋巴结转移少见，不同病理类型间淋巴结转移率存在显着差异。肿瘤大小、位置和病理亚型与淋巴结转移的风险显着相关。淋巴结转移患者的总生存期优于远处转移患者，提示对这些 AJCC IV 期 STS 患者应进行更精确的预后评估。