Current status of multimodal molecular imaging of prostate cancer

Prostate carcinoma is the most common life-threatening cancer affecting men in the western world. In Germany about 40 600 new cases have to be expected each year. The mortality is around 10%. The major goals of pretherapeutic imaging are to determine the local extent of prostate carcinoma in terms of intraprostate localisation, extracapsular extension (ECE), seminal vesicle invasion (SVI), tumour infiltration into neurovascular bundles, and if this has taken place, into surrounding tissues and organs in the small pelvis, detection of loco-regional metastases via the lymph nodes and if this so, of distant metastases. Exact pretherapeutic diagnosis and staging are essential, because the tumour treatment must be selected in strict dependence on clinical tumour stage and risk profile. Both anatomic and functional molecular imaging of prostate carcinoma have advanced significantly in recent years. When there are problems with diagnosis, e.g. when prostate punch biopsies are negative while the suspicion of prostate carcinoma persists, C-11/F-18 choline PET/CT and MRI/MRS may be helpful in localising the carcinoma, revealing how the carcinoma relates to the surrounding intra- and extraprostatic structures and organs, and making a targeted repeat biopsy possible. Lymphotropic contrast agents are highly promising for accurate nodal staging of prostate carcinoma, but are not yet available for routine clinical use. In these circumstances, the sensitivity of nodal staging with the widely available imaging modalities remains difficult. There has been particularly substantial progress in the localisation of local relapse, which can be imaged with contrast-enhanced C-11-choline PET/CT and MRI in most cases when PSA is considerably below 1 ng/ml. F-18-fluoride PET/CT has proved accurate in the diagnosis of skeletal metastases from prostate carcinoma. (orig.)