OBJECTIVETo evaluate the prognostic factors for the local recurrence of osteosarcoma in extremities treated with combined therapy.

METHODSBetween 1992 and 2001, 189 patients with non-metastatic osteosarcoma were treated. The average age at diagnosis was 18 years old. Tumors were located in the distal femur in 86 patients, proximal tibia in 52, and other locations in 51. Pathologic fracture occurred in 22 cases. One hundred and sixteen patients received combined therapy, 73 patients underwent non-combined therapy (tumor resection only or unfinished chemotherapy). In the combined therapy group, 90 patients underwent limb salvage surgery and 26 patients received amputations. In the non-combined therapy group, 42 patients underwent limb salvage surgery and 31 patients received amputations. With Chi-Square test, local recurrence rates were retrospectively evaluated in relation to gender, age, tumor site, pathologic fracture, serum level of alkaline phosphatase, protocol of chemotherapy, type of surgery, surgical margin, size of tumor, and postoperative chemotherapy. Multiple factors were analyzed by Logistic regression analysis.

RESULTSThe 5-year-survival rate was 78.5% in the combined therapy group and 35.1% in the non-combined therapy group. Local recurrence rate was 16.6% (15 cases) in limb salvage surgery with combined therapy group (90 cases) and 38.1% (16 cases) in limb salvage surgery with non-combined therapy group (42 cases) (P<0.001). Metastasis rate was 28.4% (33 cases) in the combined therapy group (116 cases) and 65.7% (48 cases) in the non-combined therapy group (73 cases) (P<0.000). The local recurrence rate was significantly related to serum level of alkaline phosphatase after preoperative chemotherapy, type of surgery, surgical margin and chemotherapy protocol. Moreover, Logistic regression revealed that surgical margin and serum level of alkaline phosphatase after preoperative chemotherapy were the key factors affecting the local recurrence.

CONCLUSIONSThe local recurrence is related to the surgical margin. The adequate surgical margin is very important for the limb salvage. The local recurrence is highly related to metastasis. The inadequate surgical treatment would damage the survival of patients with osteosarcoma.