OBJECTIVETo investigate the effects of primary tumor excision on osteosarcoma angiogenesis and pulmonary metastasis, and explore its possible mechanism and clinical significance.

METHODSThe tumor-bearing nude mice were constructed by injection of human osteosarcoma cell suspension, and divided into primary tumor resection, amputation and normal groups. The level of VEGF and endostatin was examined by ELISA assay. The hemoglobin content in Matrigel pellets was measured with HiCN method. Pulmonary metastasis was detected with dilated-squash technique and immunohistochemical staining.

RESULTSThe serum VEGF and endostatin level was significantly decreased in the primary tumor excision group compared with that in the normal and control groups after operation, but endostatin decreased more prominently [VEGF: (71.43 +/- 9.15) pg/ml vs. (115.81 +/- 4.38) pg/ml, (111.68 +/- 12.26) pg/ml, P < 0.01; ES: (40.77 +/- 5.41) ng/ml vs. (123.18 +/- 5.94) ng/ml, (128.06 +/- 4.52) ng/ml, P < 0.01]. The HB contents in Matrigel pellets increased in the primary tumor excision group compared with that in normal and control groups [(36.55 +/- 2.35) g/L vs. (16.84 +/- 1.15) g/L, (16.29 +/- 1.10) g/L, P < 0.01]. The rate of pulmonary metastasis in tumor excision group was much higher than that in the un-excised groups (80.0% vs. 40.0% and 35.0%, P < 0.05).

CONCLUSIONThe excision of primary tumor can promote osteosarcoma angiogenesis and pulmonary metastasis, so anti-angiogenic treatment after operation has instructive clinical significance in preventing tumor metastasis.