Molecular imaging in diagnostics

Abstract

Prostate cancer is the most common malignancy and the second most common cause of cancer-related mortality in men. Despite the downstaging we have observed over the last 20 years with the widespread use of PSA screening, we continue to observe conflicting data regarding its effect on prostate cancer survival [1, 2]. While treatment for localized prostate cancer is highly successful, about 30-50 % of men will experience a biochemical failure within 10 years from the primary treatment, suggesting that prostate cancer can metastasize relatively early in the course of disease [3-6]. This is supported by the discovery of circulating prostate cancer cell in bone marrow biopsy of patients with apparently localized disease [7]. A portion of men with biochemical failure will develop locally recurrent disease, and as many as two-thirds will have evidence of osseous metastatic involvement [8-11]. In the study by Pound et al. after primary surgical treatment, 15 % of patients developed biochemical recurrence. The median actuarial time to metastases was 8 years from the time of PSA relapse. Once men developed metastatic disease, the median survival time to death was 5 years [12]. If men develop castrate resistant metastatic disease, the 1-year survival is about 24 % with a median survival of only 8-18 months [13]. The hormone-refractory state is believed to occur via bypassing or sensitizing the androgen receptor (AR) signaling pathway. Patients with biochemical recurrence and metastatic disease are left with imaging modalities that neither provide enough information to change management nor are able to predict patient's prognosis or evaluate patient's treatment progress. The reason is that traditional imaging techniques are focused on evaluating the anatomy rather than the function of prostate cancer. Unlike traditional structural imaging, molecular imaging takes advantage of the functionality of tumor. These imaging techniques can theoretically provide functional information regarding prostate cancer. In this chapter, we review the current literature on the potential and emerging role of molecular imaging in prostate cancer.