Abstract
OBJECTIVE: Clear cell sarcoma (CCS) and epithelioid sarcoma (ES) are typical examples of soft tissue sarcoma subtypes that cause lymph node metastasis (LNM). However, the role of primary regional lymph node dissection remains unclear, especially when radiological evidence of LNM is absent preoperatively. We retrospectively investigated the significance of regional lymph node dissection in patients with CCS and ES. METHODS: Forty-one patients (CCS, n = 13; ES, n = 28) with no distant metastasis and with or without radiologically obvious regional LNM were enrolled in this study. Among these patients, cases without obvious LNM on imaging findings were categorized into 2 groups: the "with dissection (WD)" group and the "no dissection (ND)" group. Overall survival (OS), lymph node metastasis-free survival (LNMFS), disease-free survival (DFS), and the postoperative LNM rate were evaluated and compared between the 2 groups. RESULTS: In total, 9 patients were suspected to have LNM based on preoperative radiological examinations. All of these patients underwent regional lymph node dissection performed simultaneously with resection of the primary tumor. Histopathological examinations confirmed the presence of regional LNMs in 4 of the 9 patients. Of the remaining 32 patients without preoperative evidence of LNM, 17 belonged to the WD group and 15 belonged to the ND group. Six of the 17 patients (35.3%) in the WD group were positive for LNM in a histopathological examination. The OS (P = 0.03), LNMFS (p < 0.01), and DFS (p < 0.01) were significantly better in the WD group. The postoperative LNM rate was significantly lower in the WD group (P = 0.03). In terms of histology, there were no significant differences in OS, LNMFS, or DFS between the CCS and ES groups. CONCLUSION: Even when preoperative radiology suggested no evidence, LNM was present in > 30% of all cases. Regional lymph node dissection performed simultaneously with resection of the primary tumor showed a statistically significant prognostic improvement. LEVEL OF EVIDENCE: Prognostic studies, Level III. See Instructions for Authors for a complete description of levels of evidence.