Incidence and prognostic impact of regional lymph node metastasis at the time of diagnosis in soft-tissue sarcoma

Aims The aim of this study was to investigate the risk factors and prognostic impact of the presence of regional lymph node metastasis at the time of presentation in patients with soft-tissue sarcoma (STS), focusing on the histological sub-types. Methods This retrospective analysis, based on a Japanese registry, included patients who were diagnosed with STS between January 2006 and December 2019. Disease-specific survival was estimated using the Kaplan-Meier method. A Cox regression model was used to identify the risk factors for regional lymphatic metastasis and prognostic factors for STS. Results Among the 10,796 patients, 440 (4.1%) had regional metastasis at the time of presentation. The significant risk factors for the presence of regional metastasis were large size of tumour (> 10 cm) (p = 0.024), retroperitonal tumour (p = 0.007), high-grade tumour (p < 0.001), distant metastasis at the time of diagnosis (p < 0.001), and histological sub-types such as clear cell sarcoma and epithelioid sarcoma. Desmoplastic small round cell tumours had a high rate of regional metastasis (80%). Although it was a poor prognostic factor, patients with isolated regional metastasis had a better disease-specific survival compared with those with distant metastasis at the time of presentation. The prognostic impact of isolated regional metastasis differed according to sub-type. Identical survival was seen in patients with isolated regional metastasis and those with no regional metastasis and distant metastasis in patients with extraskeletal myxoid chondrosarcoma, synovial sarcoma, and epithelioid sarcoma. Patients with isolated regional metastasis had significantly better survival compared with cases of distant metastasis in patients with dedifferentiated liposarcoma and undifferentiated pleomorphic sarcoma, but a significantly worse survival compared with those who had no regional metastasis and distant metastasis. Conclusion The incidence of regional lymph node metastasis in patients with STS varies according to the histological sub-type; and the size of the tumour, its location, and sub-type are risk factors for the presence of regional metastasis at the time of presentation. The impact of regional metastasis on prognosis was significantly different from that of distant metastasis, and varied among the sub-types, suggesting that prognostic evaluation in patients with isolated regional metastasis should be performed according to the histological sub-type. Cite this article: Bone Joint J 2025;107-B(11):1229–1236.