By Monique Biryiana

In 2018, prostate cancer was the second most common cancer in men, with the difference in worldwide incidence reflecting the use of diagnostic testing (Rawla, 2019).

In terms of detecting prostate cancer - current methods rely on measuring the serum Prostate Specific Antigen (PSA) levels, along with additional imaging techniques such as systematic transrectal ultrasonography (TRUS) to complement the traditional biopsy procedure (De Visschere et al., 2010). However, more recently the use of multi-parametric magnetic resonance imaging (MRI) has been recently utilised as an alternative imaging tool in the identification and location of suspicious lesions – resulting in an MRI-guided biopsy procedure (Drost et al., 2019). Currently, the evidence to determine which tool to use to detect and guide these clinical decisions remains insufficient.

A review published in the Cochrane Database of Systematic Reviews, investigated the accuracy of different diagnostic methods, including using MRI alone, MRI-targeted biopsy, MRI with or without MRI-targeted biopsy (termed the “MRI pathway”) and the TRUS procedure – all in reference to a template-guided biopsy to detect clinically significant prostate cancer (Drost et al., 2019).

The investigators performed a systematic literature review using numerous databases, resulting in an in-depth analysis of 43 studies of men aged 61 to 73 years.   

Out of population of 1000 men at risk for prostate cancer (in which 300 men were confirmed with having clinically significant prostate cancer, Drost et al (2019) revealed that:

• 273 men will be correctly identified via MRI as having clinically significant prostate cancer; leaving the remaining 27 prostate cancer-men undetected. In regard to the 700 men who did not have clinically significant prostate cancer – 441 will be misclassified, and 259 men will be correctly identified as not having clinically significant prostate cancer.
• MRI-targeted biopsy will diagnose 240 men with clinically significant prostate cancer but will miss the remaining 60 men. As with the men who did not have prostate cancer – 658 men will be correctly identified, leaving 42 men with a misclassified diagnosis.
• The use of the MRI pathway, will successfully identify 216 out of 300 men with prostate cancer but will fail to identify the outstanding 84 men. In contrast, 672 men will be correctly identified as not having prostate cancer, with 28 men being classified with a false diagnosis.
• Systemic biopsies were found to successfully identify 189 out of 300 men with clinically significant prostate cancer – however, the 111 men will remain undetected. Surprisingly, this method correctly identified all 700 men with clinically significant prostate cancer.

These findings therefore demonstrate the accuracy of the MRI pathway as a preferred method to detect significant prostate cancer - especially when compared to systematic biopsy. It was reported that the MRI pathway is 12 percent more likely to make a correct diagnosis in a mixed population of men who may or may not have had a prior biopsy. However, the effective use of this clinical tool warrants further research, due to the inconsistencies in detecting significant cancer in some men. The reliability of this research is also questionable and is reduced by the limitations of the study – including the low quality of the studies included. The authors of this review noted that the addition of higher quality studies may influence these results (Drost et al., 2019).

Read the full review here.

References: 

De Visschere, P., Oosterlinck, W., De Meerleer, G. and Villeirs, G. (2010). Clinical and imaging tools in the early diagnosis of prostate cancer, a review. Journal of the Belgian Society of Radiology, 93(2), p.62.

Drost, F., Osses, D., Nieboer, D., Steyerberg, E., Bangma, C., Roobol, M. and Schoots, I. (2019). Prostate MRI, with or without MRI-targeted biopsy, and systematic biopsy for detecting prostate cancer. Cochrane Database of Systematic Reviews.

Rawla, P. (2019). Epidemiology of Prostate Cancer. World Journal of Oncology, 10(2), pp.63-89.