Is it important to maintain high-dose intensity chemotherapy in the treatment of adults with osteosarcoma?

Neoadjuvant chemotherapy for osteosarcoma is the standard of care, but there is still confusion regarding the best chemotherapy regimen and the optimal intensity. This retrospective study intends to evaluate whether there is a clear correlation between the chemotherapy dose intensity (DI) and the percentage of tumor necrosis, the risk of tumor recurrence after surgery and patient survival. The medical records of all adult patients with localized osteosarcoma that received treatment between the years of 1998 and 2009 at the Tel Aviv Sourasky Medical Center were analyzed. We used multiple logistic/linear regression models to test the effect of the neoadjuvant chemotherapy relative DI (RDI) on histological response, recurrence and time to recurrence. A Cox regression analysis was conducted for the effects of neoadjuvant chemotherapy RDI, histological response, tumor location, gender and age on patient survival. Thirty medical records were analyzed. Survival, histological response, recurrence and time to recurrence were not affected by the chemotherapy RDI. The 5-year overall survival of the patient's population was found to be 63% with a median survival of 9.4 years. Patients with a good histological response had a longer survival than those with a bad response (mean survival times 11.0 vs. 6.6 years, log-rank test, P = 0.046). High DI is not a prognostic factor in osteosarcoma and maintaining it should not be a prime priority. Histological response is a prognostic but possibly not a reliable predictive factor, and further research is needed in order to find other reliable factors.