Pathologic fracture after radiation therapy for primary non-Hodgkin's malignant lymphoma of bone.

Between 1963 and 1981, 32 patients with biopsy proven non-Hodgkin's lymphoma involving bone were treated at the Mallinckrodt Institute of Radiology either with radiation alone or in conjunction with chemotherapy. An unexpectedly high rate of fracture at the site of the tumor was observed. Six patients were excluded because they survived less than six months after the completion of radiotherapy or were lost to follow-up within six months. There were 15 appendicular and 17 axial sites treated. Local control was achieved in 30 of 32. There were 10 patients with appendicular lesions of which seven suffered a fracture. Of the seven patients with lesions in a weight bearing bone, six suffered fractures. Twenty-six sites of involvement received less than 5000 rad. Five sites of involvement with diffuse histiocytic lymphoma (DHL) involving the appendicular skeleton received 5000 to 6000 rad. One site with DHL involving the axial skeleton received 5000 rad. Of the six patients receiving high dose, two presented with pathologic fractures of the femur requiring surgical stabilization and the remaining four patients suffered subsequent fractures 7 to 30 months after completion of therapy. Two of these six had local recurrence of disease. It appears that involvement of the appendicular skeleton by lymphoma frequently results in fracture. Doses of 5000 rad or greater do not increase the probability of local control but may contribute to the risk of fracture following radiotherapy.