Tumor-cell heterogeneity in soft tissue sarcomas as defined by chemoradiotherapy

This report documents heterogeneous cell populations within high-grade soft tissue sarcomas in seven patients. The authors observed that, following chemoradiotherapy (five patients) or chemotherapy alone (two patients), surgically resected residual or recurrent sarcoma was found to be of low-grade histology. All chemotherapy was of Adriamycin (doxorubicin)-containing combinations. Seven other patients with regional recurrence after resection of high-grade sarcomas had high-grade recurrent tumors. Five of these patients had received no adjuvant therapy; two with extensive retroperitoneal liposarcomas and gross tumor-involved margins had received chemoradiotherapy. Follow-up ranged from 3 to 60 months (median, 12 months). These findings suggest that high-grade populations of sarcoma cells are more susceptible to chemoradiotherapy, as long as there is minimal residual disease. Low-grade clones of tumor cells may survive such therapy and present as clinical recurrence after initial treatment of low-grade or high-grade soft tissue sarcomas. Surgical resection is warranted for these recurrent lesions.