Tin-117m(4+)-DTPA for palliation of pain from osseous metastases: a pilot study

The physical and biological attributes of 117mSn(4+)-DTPA indicate that it should be an effective agent for palliative therapy of painful bony metastatic disease. The aim of this study was to evaluate whether or not this agent could effectively reduce pain while sparing the hemopoietic marrow from adverse effects.

Fifteen patients (10 males and 5 females) with painful bony metastases from various primary cancers were included in the study. Seven patients received 1.22 to 3.11 MBq/kg of 117mSn intravenously (Group 1) and eight patients received 4.85 to 5.77 MBq/kg (Group 2). All but one were treated as outpatients and followed for a minimum of 2 mo.

In the first group, pain relief was non-assessable in four patients because of death or additional treatment of soft-tissue disease by another modality. One patient had no relief of pain, one had complete relief of pain and one had transient relief of pain. No myelotoxicity was observed. For Group 2, three patients achieved complete relief of pain, two good relief, two partial relief and one began to experience pain relief when he suffered a pathological fracture 2 mo post-treatment. None of these patients had myelotoxicity.

Tin-117m(4+)-DTPA can reduce pain from metastatic disease to bone without inducing adverse reactions related to bone marrow. Further studies are needed to assess tolerance levels for the bone marrow and to evaluate response rates and duration of effect.