Prostatic Carcinoma

KEY FACTS

Imaging

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Grayscale US
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  Prostate carcinoma (PCa) can appear as hypoechoic (60-70%), isoechoic/invisible (30-40%), rarely hyperechoic ± asymmetric capsular bulging or irregularity
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Color Doppler US
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  PCa may be hypervascular; however, absence does not exclude cancer, and other benign entities (e.g., prostatitis) may also be hypervascular
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Transrectal US (TRUS) is imaging of choice to guide biopsy in evaluation for PCa but performs poorly in cancer detection and staging
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Calculate prostate volume using largest cross-sectional image in transverse and mid sagittal planes: Transverse x AP x long x 0.52
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MR imaging
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  Most sensitive imaging technique for PCa diagnosis and staging
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  Peripheral zone (PZ): T2 dark lesion with restricted diffusion; transition zone (TZ): Erased charcoal sign on T2WI
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  Targeted MR-guided and MR/US fusion-guided biopsy is promising for increasing detection of high-risk prostate cancer while reducing detection of low-risk cancer compared with standard biopsy

Pathology

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Most common noncutaneous malignancy in western world, 2nd most common cause of cancer deaths among men
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95% of tumors are acinar adenocarcinoma
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Staging based on tumor-node-metastasis staging, prostate specific antigen at time of diagnosis, and Gleason score
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Location of prostate cancer: PZ: 70-80%, TZ: 20%, central zone: 1-5%

Clinical Issues

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Management is complex due to difficulty in accurate staging and in predicting speed of disease progression
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Despite having higher volumes and prostate-specific antigen values at diagnosis, TZ cancers are less likely to be associated with seminal vesicle, extraprostatic and lymphovascular invasion

Scanning Tips

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Although classically PCa is hypoechoic on grayscale US, > 30-40% PCa may be invisible on TRUS

Longitudinal graphic shows advanced prostatic carcinoma (PCa) with extracapsular spread to the adjacent pelvic structures, such as the bladder

, rectal wall

, and symphysis pubis

Transverse TRUS shows a hypoechoic left PZ lesion

with capsular bulging and nodularity extending into the adjacent fat

and left neurovascular bundle

. A smaller hypoechoic lesion is seen in the right PZ

Corresponding Doppler US shows focal hypervascularity

in the left PZ lesion. The right PZ lesion is mildly hypervascular

. Prostatectomy revealed multifocal PCa, including Gleason 5 + 5 adenocarcinoma with left extraprostatic extension and lymphovascular and perineural invasion.