Recently reported data from  the National Cancer Institute Surveillance, Epidemiology, and End Results Program (SEER) demonstrate that approximately 90% of patients, regardless of race, were diagnosed with localized prostate cancer between 1995 and 2000. Currently, in the Las Vegas area, I have noticed a trend of diagnosis with more advanced disease (this is my observation). Likely, this multifactorial problem is because too often patients are referred after a significant prostate rise has been detected.

 

Regardless, various forms of noninvasive imaging have been used to evaluate patient who have prostate cancer, but the clinical utility of standard cross sectional imaging is limited because a relatively large volume of disease is generally required for detection.

 

Transrectal ultrasound is the most common modality. Mostly it is used almost for staging and biopsies. The higher frequency transducers improved prostate images. Typically, the hypoechoic lesions were thought to be more likely to be cancerous. However, the isoechoic surrounding lesions frequently contain cancer cells. 80% of hypoechoic prostate cancer do not reprensent prostate cancer. 50% of nonpalpable prostate cancers are not visulized by sonography.

 

Color Doppler and power doppler, which are based on the premise of increased or altered microvessel blood blow within cancerous areas, have been inconclusive for cancer detection within the glans. Flurocarbon microbubble sonographic contrast agents have been evaluated as a method to increase the amplitude of a reflected signal in the blood pool. There seems to be a greater (2-3x) chance of detecting cancer, however,  whether this modality has utility for detection of locally advanced disease has not been determined.

 

We recently looked into the use or MRI at our local hospital for the detection of cancerous lesions. The use of an endorectal coil is mandatory (we do not have one). It is interesting to see lesions visible because of their high density of blood vessels by MRI. It is a detection modality that is best suited for high risk patients at centers capable of using this technology. It should be a few years before it becomes reliable.

 

Bone scans are the mainstay to detect cancer involvement within the skeleton. A normal x-ray will detect changes secondary to cancer after 50% has been changed. A scintigraphy can detect changes after only 10% has been changed.  Nowadays, prostate cancer is detected at earlier stages, bone scans are recommended only when the PSA is greater than 10.

 

Positron emission tomography measures metabolism of a radio-labeled analog in tissue where where the higher metabolic rate of neoplasia registers an increased signal, which is especially noted in rapidly progressive tumors. Although the most commonly used radiotracer for PET is FDG, this analog is not particularly useful to evaluate prostate cancer.

 

Manyak M, Javitt, et al. Evolution of Imaging in Advanced Prostate Cancer, 2007. Urology Clinics 2007; 33:133-146.