Clinician-to-Clinician Update Clinician-to-Clinician Update

MRI/Ultrasound Fusion Biopsy Reveals Advanced Cancer after Prior Negative Tests

July 2015

Contributed by Badrinath R. Konety, MD

Anterior prostate tumors account for about one-fifth of all prostate cancers. They are more difficult to diagnose and yield smaller areas of cancer on core biopsies than do posterior tumors in glands of similar weight and tumor volume.1 Here we describe the case of a 64-year-old male patient with a long history of obstructive urinary symptoms and rising PSA but whose ultrasoundguided biopsies were negative. MRI-guided biopsy with transrectal ultrasound fusion was successfully used in our center, enabling a diagnosis of advanced anterior disease and a positive surgical outcome to date.

Patient

A 64-year-old gentleman was referred in 2014 to the University of Minnesota Medical Center’s Institute for Prostate and Urologic Cancers with a rising PSA but otherwise negative prostate cancer workup. He had long history of obstructive urinary symptoms, described as a weak stream, increased frequency, and nocturia. The patient had previously been diagnosed in 2005 with benign prostatic hyperplasia, and his PSA levels had been steadily increasing since that time. Standard transrectal ultrasound-guided 12-core biopsies in 2007 and 2009 were negative for cancerous lesions. A saturation biopsy in 2013 was also negative. On presenting to the hospital, the patient’s PSA level was 22. (Most physicians consider PSA levels of 4.0 ng/mL and lower as normal.)

prostate-ultrasound Fig1-443x293
— Figure 1. Ultrasound image showing the prostate gland (outlined in red) with a mass in the anterior right central location that was highly suspicious for malignancy.

Treatment and Management

The patient opted to undergo an MRI-guided biopsy with transrectal ultrasound fusion, which revealed an anterior lesion with a Gleason score of 8 (Figures 1-2). (A system that rates the likelihood that prostate cancer tissue will spread, Gleason scores range from 2-10, with the most commonly found grades being from 6-10 and 10 marking most aggressive growth.) 

The patient underwent a robotic-assisted radical prostatectomy with bilateral pelvic lymph node dissection and recovered without sequelae. Currently there is no evidence of disease. The patient continues to receive active surveillance care with routine PSA level checks.

prostate-MRI-ultrasound-fusion Fig2-443x293
— Figure 2. MRI/ultrasound fusion 3D image of the prostate gland (red) showing the anterior lesion (green) with biopsy core targets (circled).

Discussion

Most techniques for detecting prostate cancer, such as digital rectal examination, transrectal ultrasoundguided biopsy and endorectal-coil MRI, rely on a transrectal approach for diagnosis. Because anterior prostate cancers are distant from the rectal surface, they can be difficult to detect by these means and can be a challenge to visualize and sample.2 In the hands of an experienced practitioner, MRI-guided biopsy with transrectal ultrasound fusion dramatically increases the detection of anterior zone disease. In a recent study, 499 patients with clinical suspicion of prostate cancer who had previously undergone an MRI-guided biopsy were re-biopsied using MRI/transrectal ultrasound fusion technology. The fusion biopsy revealed a total of 241 anterior lesions in 162 patients, but only 62 (25.7%) of these anterior lesions had been documented as positive for cancer on the previous MRI-guided biopsy cores.3 In the above case, the patient had undergone 2 transrectal-ultrasound guided biopsies followed by a saturation biopsy, all of which were negative. Upon referral to our center, MRI-guided biopsy with transrectal ultrasound fusion revealed advanced disease in the anterior prostate, which was to date successfully treated with radical prostatectomy.

References

1. Bott SR, Young MP, Kellett MJ, et al. Anterior prostate cancer: is it more difficult to diagnose? BJU Int. 2002;89:886-889.

2. Koppie TM, Bianco FJ, Kuroiwa K, et al. The clinical features of anterior prostate cancers. BJU Int. 2006;98:1167-1171.

3. Volkin D, Turkbey B, Hoang AN, et al. Multiparametric magnetic resonance imaging (MRI) and subsequent MRI/ultrasonography fusionguided biopsy increase the detection of anteriorly located prostate cancers. BJU Int. 2014;114:E43-49.

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