Tertiary Lymphoid Structures Correlate With Better Prognosis in Patients With Retroperitoneal Sarcoma: A Retrospective Study.

OBJECTIVE

To evaluate the prognostic impact of intratumoral tertiary lymphoid structures (TLSs) in patients with retroperitoneal sarcoma undergoing primary curative surgery, focusing on their relationship with immune microenvironment components and survival outcomes.

METHODS

We conducted a retrospective analysis of 29 patients who underwent surgical resection for retroperitoneal sarcoma at Dokkyo Medical University Hospital from 2007 to 2021. TLSs and tumor-infiltrating lymphocytes were assessed in surgical specimens using immunohistochemical staining to identify CD20-positive B, CD3-positive T, and CD8-positive T cells. Disease-specific survival was analyzed via Kaplan-Meier and Cox proportional hazards models, identifying key prognostic factors.

RESULTS

TLSs were identified in 59% of patients, with the highest density in dedifferentiated liposarcoma (DDLPS). TLS-positive patients showed significantly improved survival compared with TLS-negative patients, with the greatest survival observed in those with ≥ 10 TLSs per 100 mm. TLS density was also associated with increased CD8-positive T-cell infiltration, indicating a potentially enhanced immune response. In the subset of DDLPS cases, TLS positivity correlated with prolonged survival, underscoring its prognostic value.

CONCLUSIONS

Intratumoral TLSs are associated with improved survival in retroperitoneal sarcoma, especially DDLPS. These findings highlight the need for further studies on the role of TLS maturity and immune microenvironment dynamics in shaping prognosis and treatment outcomes in retroperitoneal sarcoma.