Introduction

Nuclear medicine is a highly sensitive technique for detecting metastatic disease at sites throughout the body using radiotracers as biomarkers of cancer biology. Radioactive signals from these radiotracers are detected by sophisticated radioactivity-detector imaging systems including single-photon-emission computerized tomography (SPECT) and positron-emission tomography (PET). In this way nuclear medicine imaging is an example of “functional” or “molecular imaging” in which the imaging itself is based on a biochemical or physiologic property of the imaged tissue. For the patient with prostate cancer, nuclear medicine techniques, when used judiciously, are an important part of optimized cancer care; for example, bone scans are very commonly used to detect and follow up skeletal metastatic disease.

The clinical states model of Scher and Heller provides a useful guide to the possible progression of prostate cancer from a localized disease to widely spread tumor [1,2, 3] (Figure 11.1).

From the standpoint of natural history and chance of progression in the individual patient, prostate cancer is one of the most variable of all tumors. The cancer itself may behave in a highly indolent matter and be localized in the prostate gland for years, with the patient's death being due to other diseases. Then again, a localized tumor may rapidly progress, become widely metastatic within a short time and lead to death.

Fortunately, clinical trials are now resolving key management questions based on objective features of cancer histology and biochemistry.