Incidence, risk factors, and prognostic impact of regional lymph node metastasis in bone sarcoma: a population-based cohort study.

Abstract

Background: This study aimed to investigate the risk factors and prognostic impact of regional lymph node metastasis (RLNM) in patients with bone sarcoma.

Methods: This retrospective study analyzed data from a Japanese registry of patients with bone sarcoma (2006-19). Disease-specific overall survival was estimated using the Kaplan-Meier method. A Cox regression model was used to identify risk factors for RLNM and prognostic factors.

Results: Among 5064 patients, 157 (3.1%) had RLNM. The incidence varied by histological subtype: 7.6% in Ewing sarcoma, 3.1% in osteosarcoma, 1.6% in chondrosarcoma, and 5.2% in undifferentiated pleomorphic sarcoma. Higher rates were observed in rare subtypes, including mesenchymal chondrosarcoma (12.9%) and dedifferentiated chondrosarcomas (10.3%). Risk factors for RLNM included older age, tumor size (>8 cm) (P = .02), distant metastasis at diagnosis (P < .0001), skip metastasis (P < .0001), and histological subtype (e.g. Ewing sarcoma and dedifferentiated chondrosarcoma). RLNM was associated with poor prognosis (HR 1.69, 95% CI: 1.35-2.1, P < .0001), with isolated RLNM conferring survival outcomes equivalent to those with distant metastasis. Among RLNM cases, skip metastasis was the only significant independent predictor of poor prognosis (HR 2.41, 95% CI: 1.35-4.30, P = .003).

Conclusions: The incidence of RLNM in bone sarcomas varies by histological subtype. Risk factors include older age, tumor size, distant metastasis, skip metastasis, and histological subtype. Isolated RLNM has a prognosis comparable to that of distant metastases, and skip metastasis is a significant negative prognostic factor.