Use of samarium Sm 153 lexidronam for the treatment of dogs with primary tumors of the skull: 20 cases (1986-2006).

Objective: To evaluate samarium Sm 153 lexidronam ((153)Sm-EDTMP) as a treatment option for dogs with bony tumors of the skull.

Design: Retrospective case series.

Animals: Dogs with multilobular osteochondrosarcoma (MLO) or osteosarcoma (OSA) of the skull.

Procedures: Veterinary Medical Teaching Hospital records from the Universities of Missouri and Florida from 1986 to 2006 were searched for dogs with primary skull tumors treated with (153)Sm-EDTMP.

Results: 25 dogs were initially evaluated, with 5 dogs subsequently excluded because of inadequate follow-up or unrelated death. Seven OSAs and 13 MLOs were diagnosed. Tumors involved the occipital and frontal bones (n = 10), zygomatic arch and maxilla region (6), palate (3), and mandible (1). No clinically important adverse effects related to (153)Sm-EDTMP treatment were documented. Of the 20 dogs evaluated 21 days after injection with (153)Sm-EDTMP, 4 had subjective improvement, 13 had progressive disease, and 3 had insufficient follow-up. On the basis of radiographic findings, metastasis was suspected in 1 dog; 16 dogs had no metastasis evident, and medical records were insufficient for 3 dogs. Survival time, defined as the (153)Sm-EDTMP injection date to the date of death, ranged from 3 to 1,314 days (median, 144 days).

Conclusions And Clinical Relevance: The subjective improvement in 4 patients and lack of clinical evidence of adverse effects suggested that (153)Sm-EDTMP injection may be an option for the treatment of dogs with MLO or OSA of the skull when other treatments have failed or surgery is not possible.