IMPACT OF NEOADJUVANT IFOSFAMIDE-BASED REGIMENS ON THE CLINICAL AND HISTOLOGIC RESPONSE OF CHILDHOOD OSTEOSARCOMA

Osteosarcoma is the most common malignant bone tumor in children and a dolescents. Chemotherapy has significantly improved the disease-free s urvival in these patients, but still nearly 40% succumb to the disease . In an attempt to improve the rate of cure of osteosarcoma, other age nts such as ifosfamide are being evaluated. Clinical progression durin g neoadjuvant chemotherapy is an obvious sign of lack of sensitivity o f the tumor to the agents used. It has also been documented that the p ercentage of tumor necrosis after presurgical chemotherapy is an indic ator of the tumor's sensitivity to chemotherapy and has important prog nostic significance. To examine the impact of ifosfamide-containing re gimens on the clinical and histologic response of osteosarcomas to neo adjuvant therapy, we reviewed the medical records and pathology report s of 50 patients with osteosarcoma treated with neoadjuvant chemothera py between March 1981 and February 1995. Eighteen patients received ne oadjuvant regimens containing ifosfamide; 32 patients were treated wit h neoadjuvant regimens without ifosfamide. Clinical characteristics we re similar for the two groups. Of 9 patients whose tumors clinically p rogressed during neoadjuvant therapy, none had been treated with ifosf amide-containing regimens. A good response (90% or greater tumor necro sis) occurred in 12 of 18 patients (67%) treated with ifosfamide-conta ining regimens and 10 of 32 patients (31%) treated with regimens witho ut ifosfamide (p < .05). Overall disease-free survival was 73% for pat ients treated with neoadjuvant ifosfamide and 53% for patients treated with neoadjuvant regimens without ifosfamide. Our results indicate th at neoadjuvant ifosfamide-containing regimens improve the clinical and histologic response in patients with osteosarcoma compared with stand ard neoadjuvant regimens without ifosfamide.