Unsealed source therapy of painful bone metastases: an update

Pain in patients with cancer metastatic to bone is a significant cause of morbidity and of referrals from general practice and specialist physicians. Management typically utilizes radiation therapy and the graduated use of opiate analgesics. Bone-seeking radiopharmaceuticals have provided a new option to these management strategies, which is effective and cost effective. Strontium 89 is now in routine clinical use, while rhenium 186 hydroxyethylidene diphosphonate (HEDP) and samarium 153 ethylenediaminetetramethylene phosphonate (EDTMP) are in Phase III trials and tin 117m (4+) diethylene triaminepentacetic acid (DTPA) is in Phase I trials. Evidence taken primarily from the Strontium 89 trial, shows unsealed source therapy with these bone-seeking radiopharmaceuticals to be effective in palliating pain, improving quality of life, reducing the rate at which new painful sites develop, reducing requirements for additional radiation therapy, and reducing lifetime management costs. Indications and contraindications to therapy have now been defined, and retreatment is an option with all radiopharmaceuticals.