Relationship between dose-intensity of treatment and outcome for patients with osteosarcoma of the extremity treated with neoadjuvant chemotherapy

One-hundred and forty-four patients with osteosarcoma of the extremity treated with neoadjuvant chemotherapy at the authors' institution between 1986 and 1989 were retrospectively analyzed to evaluate the relationship between the dose-intensity of chemotherapy actually received (RDI) and the prognosis. Preoperative chemotherapy consisted of high-dose methotrexate i.v., cisplatin i.a., and doxorubicin i.v. After surgery 'good responder' patients (90% or more tumor necrosis) had a 31-weeks of chemotherapy with the same drugs, while 'poor responder' patients (less than 90% tumor necrosis) received a 40 weeks treatment with ifosfamide and etoposide added to the three drugs used preoperatively. Due to delays and dose-reductions, only 17 patients (12%) received the treatment exactly as scheduled by the protocol, 66 (46%) received a dose-intensity between 90 and 99%, and 61 (42%) a dose-intensity between 63 and 89%. At a follow-up ranging between 10 and 13 years, 97 patients (67%) remained continuously free of disease, 45 relapsed, and two died of doxorubicin-induced cardiopathy. The continuos disease-free survival (CDFS) was not related to patients' gender and age, tumor histology, site and size, serum value of alkaline phosphatase, type of surgery and histologic response to chemotherapy. According to the RDI, CDFS resulted significantly higher for those 81 patients who received 90% or more of the scheduled dose-intensity than for those 61 who had less than 90% of the scheduled dose-intensity (76.5% v.s. 57.3%; p <0.02). These results seem to suggest that in neoadjuvant treatment of osteosarcoma the dose-intensity of chemotherapy is crucial for outcome, therefore every effort should be made to avoid reductions of doses and/or delays in performing the cycles of chemotherapy.