Outcome of re-excision for intralesionally treated parosteal osteosarcoma.

BACKGROUND: The purpose of this study is to evaluate the risk of subsequent local recurrence (LR) and survival of parosteal osteosarcoma (POS) patients who underwent re-excision after intralesional excision.

METHODS: We analyzed clinical outcomes of 11 POS patients referred after intralesional excision. Average follow-up was 86 months (range: 37-190 months). There were 9 Stage IB lesions and 2 Stage IIB lesions. Tumors were located in the femur (3) and in other locations (8). Seven patients showing recurrent tumor at referral received entire segmental excision while remaining four patients without LR underwent hemi-cortical excision.

RESULTS: The 5-year metastasis free survival rate of 11 patients was 81.8%. Patients without evident tumor mass did not show further recurrence after re-excision. However, 5 (71.4%) of the 7 patients with recurrent tumor relapsed despite segmental re-excision, and their median interval to subsequent LR was 18.8 months (range: 4-9 months). Two of five patients with re-recurrence developed metastases which were unresponsive to chemotherapy.

CONCLUSIONS: Following inadvertent intralesional procedure, re-excision should be liberally applied before there is an evidence of recurrence. In patients presenting with gross LR, amputation should not be spared unless wide surgical margin can be achieved.