High grade soft tissue sarcoma of the flexor fossae. Size rather than compartmental status determine prognosis

High grade soft tissue sarcoma arising in the popliteal space, axilla, and antecubital fossae (flexor fossae tumors) have by convention been classified as extracompartmental tumors by the accepted staging and grading criteria of the Musculoskeletal Tumor Society (MSTS). Advances in neoadjuvant chemotherapy and radiation therapy have made surgical resection more feasible. The hypothesis to be tested is that compartmental status may not be of prognostic significance if the tumor is adjusted for size, histologic grade, and distant metastasis after undergoing adjuvant chemotherapy and radiation.

From June 1976 to December 1992, 22 patients with high grade soft tissue sarcomas of the flexor fossae (Group A) were treated at UCLA Medical Center. The histologic subtypes were liposarcoma (five), synovial cell sarcoma (eight), malignant fibrous histiocytoma (four), leiomyosarcoma (two), angiosarcoma (two), and rhabdomyosarcoma (one). The popliteal fossa was the location in 11, the axilla in 10, and the antecubital fossa in 1. Wide resection was attempted in all patients after preoperative chemotherapy and radiation therapy. Amputation was performed in 5 patients because of repeated or extensive recurrent tumor. A group of 77 patients (Group B) with high grade soft tissue sarcoma located within an extremity compartment were chosen to test the hypothesis that survival of patients with tumors in the flexor fossae is equal to that of patients with intracompartmental tumors of similar size and grade if both are given adjuvant therapy. This group was chosen so that histologic subtype, size, sex, and location would be similar in the two groups. The authors selected thigh and calf tumors for comparison with popliteal fossa tumors and periscapular, deltoid, and arm tumors for comparison with axilla and antecubital fossae tumors. All of these patients had similar treatment and follow-up protocols. The median follow-up of survivors in Group A was 104 months and for patients in Group B was 79 months.

The 5-year cumulative survival rate (Kaplan-Meier method) of patients in Group A was 76%, and 67% for those in Group B. The difference was not significant. Three patients in Group A (14%) and 17 (22%) in Group B had local tumor recurrence. Eight patients in Group A (36%) and 27 (35%) in Group B had lung metastases. Age, sex, histologic subtype, and surgical margins did not affect survival outcomes, lung metastasis, and local recurrence. However, patients with larger tumors (maximum dimension > or = 8 cm or cross-sectional area > or = 40 cm2) had significantly poorer survival, more metastases, and local recurrences.

Flexor fossae sarcomas do not have a poorer prognosis than extremity intracompartmental tumors when adjusted for size, distant metastasis, and histologic grade when they are treated with adjuvant radiation therapy, chemotherapy, and surgery.