The Role of Radiotherapy in Oseosarcoma
A survey of the literature shows that the experience with radiotherapy (RT) in the local treatment of osteosarcoma (OS) is limited. This is due to various reasons: OS is a rare tumor and surgery is the treatment of choice with high local control rate, and uncertainty exists in regard to the efficacy and tolerance of radiotherapy. Publications on this topic were analyzed and will be reviewed. Furthermore, experience from the Cooperative Osteosarkomstudiengruppe (COSS)-Registry, including 100 patients (pts) treated using radiotherapy for OS, was analyzed.
The COSS-registry includes a total of 175 pts (5% of all pts) with histologically proven OS irradiated over the period of 1980−2007. 100 pts were eligible for analysis. The median age was 18 (3–66) years. Indication for RT was a primary tumor in 66, a local recurrence in 11, and metastases in 23 pts. 94 pts got external photontherapy; 2 pts, proton therapy; 2 pts, neutron therapy; and 2 pts, intraoperative RT. In addition, a group of 17 pts received bone-targeted radionuclide therapy by samarium-153-EDTMP-therapy alone or in combination with external RT. The median dose for external RT was 55.8 Gy (30–120). All the pts received chemotherapy in accordance with different COSS-protocols.
The median follow-up was 1.5 (0.2–23) years. Survival and local control rates at 5 years were calculated, and univariate and multivariate analyses performed. 41 pts are alive, 59 pts died. The overall survival rate after biopsy was 41% at 5 years, while the overall survival rates after RT for the whole group, for treatment of primary tumors, local recurrence, and metastases were 36%, 55%, 15%, and 0% respectively.
In 41 cases, local control was achieved, whereas local progression or local recurrence occurred in 59 cases, with a median time to local recurrence of 0.5 (0.1–4) years after RT. 15 pts were nonresponders to radiotherapy. Local control for the whole group was 30%. Local control rates for combined surgery and RT were significantly better than those for RT alone (48% vs. 22%, p=0.002). Local control for treatment of primary tumors, local recurrence, and metastases were 40%, 17%, and 0% respectively. Local control for pts given an addition of samarium-153-EDTMP was poor, though not statistically significant . A dose of over 60 Gy had no significant effect on local control. Prognostic factors for survival were indication for RT, RT plus surgery vs. RT alone and tumor location. Prognostic factors for local control were indication for RT, and RT plus surgery vs. RT alone.
For the majority of pts, surgery remains the local treatment of choice. Radiotherapy is an important option as local treatment of unresectable tumors, following intralesional resection, or as palliation of symptomatic metastases. Survival prognosis of such pts, however, is poor. Despite the fact that many of these pts will eventually die, they may benefit in terms of prolonged survival and prolonged local control. The combination of surgery, radiotherapy, and chemotherapy can be curative. The consistent use of full-dose chemotherapy is of importance for the response to radiotherapy. Prognostic factors for survival are indication for RT, RT plus surgery vs. RT alone and tumor location. Prognostic factors for local control are indication for RT, and RT plus surgery vs. RT alone.
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