[Effect of high and low doses of methotrexate (MTX) on bone mass in subjects treated for osteosarcoma of the limbs].

Twenty-three patients with highly malignant localized osteosarcoma receiving neoadjuvant chemotherapy with MTX randomly administered at high (7500 mg/m2) and low (750 mg/m2) doses underwent serial densitometric controls at the start of treatment and after 18 and 36 months. Increasing BMC levels at both examination points were observed in all subjects examined over time, but, contrary to findings in the control group, this increase was not statistically significant using the paired T test. Significantly lower BMC levels in relation to the control group were only found in the group treated with high doses of MTX at MDP but not PM. Reduced density at MDP alone, a site in which trabecular bone is prevalent, shows that MTX predominantly acts at the level of the latter in line with its greater sensitivity to the action of osteopenic agents.