Introduction

At the time of diagnosis a large proportion of patients have locally advanced or metastatic disease with skeletal metastases frequently a cause of significant pain. This pain may be deep and unremitting and a cause of significant morbidity.

Prostate malignancy is described as having a biclonal composition with hormone-sensitive and hormone-resistant cell lines. Surgical (orchidectomy) and medical hormone manipulation has a role in management, often achieving rapid subjective and objective therapeutic response. A significant proportion of patients never respond to hormone manipulation and the majority of patients who do respond initially will later escape from hormonal control and later develop progressive, usually symptomatic disease.

With painful skeletal metastases, external beam radiotherapy may serve to control limited disease and analgesic (narcotic) medications have an obvious benefit. However when skeletal metastases are widespread or side effects from narcotics exceed benefit, the option of Strontium therapy should be considered a viable alternative.

Strontium - 89 is a pure beta particle emitter with negligible gamma radiation emission. Beta particles have a range of 3.5 mm in bone and 6-7 mm in soft tissues. Consequently there is targeted irradiation of metastatic lesions with minimal irradiation of healthy tissues distant to metastases.

In view of the potential myelo-suppression associated with use, repeat doses of Strontium for pain recurrence are withheld for at least 3-4 months and ideally 6 months from initial dose.

John Mulholland

North Coast Radiology. Radiologist and specialist in nuclear medicine