Can rectal ultrasound detect prostate cancer? How to detect prostate cancer?

Prostate cancer is the most common cancer in men. Transrectal ultrasound has become an extension of the urologist's finger in the early detection of prostate cancer. Transrectal ultrasound is also widely used to provide brachytherapy and cryotherapy for prostate cancer.

Transrectal Ultrasound for Prostate Cancer

1. Color Doppler

Color Doppler scanning has been used to enhance the diagnosis of prostate cancer as an adjunct to transrectal ultrasonography. Some researchers have demonstrated that the addition of color Doppler improves the specificity of prostate biopsy findings. However, differentiating a focus of prostatitis from cancer is difficult. Adding power Doppler is disadvantageous.

2. Microbubble contrast agents

The use of microbubble contrast agents can enhance grayscale and Doppler imaging. Newer agents that are retained in the vascular compartment have been used for prostate imaging. Contrast-enhanced prostate ultrasonography has been evaluated by several investigators, and the addition of such contrast agents helps guide biopsies to the appropriate site; however, the additional cost of this technique may be a limiting factor to its widespread use.

3. High-intensity focused ultrasound

Using ex vivo HIFU high intensity focused ultrasound, hyperthermia can be achieved in the target tissue. The prostate can be easily treated in this way via a transrectal probe. The size of the thermal lesion can be controlled by the power and duration of the ultrasound pulse. Higher in-situ intensities can produce cavitation and bubble effects that are difficult to monitor.

4. Elasticity imaging

Elasticity imaging has been shown to be a useful tool for detecting prostate cancer. Systematic biopsy guided by color Doppler transrectal ultrasonography is the cornerstone of prostate cancer diagnosis. As mentioned previously, transrectal ultrasonography has not been proven to be a reliable imaging technique for locating cancer lesions within the prostate. Elasticity imaging is an ultrasound tool that is able to map the stiffness of prostate tissue. There are two elasticity imaging techniques: quasi-static and shear wave. The quasi-static technique involves analyzing the deformation of the prostate tissue before and after compression by the ultrasound transducer. This difference in deformation is used to estimate tissue stiffness. Reduced deformation generally indicates neoplastic tissue; furthermore, if this tissue appears hypoechoic, it may be malignant. The shear wave technique does not require compression of the rectal wall but is based on the measurement of the velocity of the shear waves propagating through the tissue.

Elastography certainly holds promise as an alternative to conventional transrectal ultrasonography, and further clinical trials are currently underway, which may provide a better understanding of the exact role of elastography in the management of prostate cancer.

Contraindications to transrectal ultrasonography-guided prostate biopsy include acute painful perianal disease and bleeding diathesis. Generally, patients should not take aspirin or nonsteroidal anti-inflammatory drugs for at least 15 days before the procedure, but recent use of these drugs should not be considered an absolute contraindication to prostate biopsy.