MRI/ultrasound fusion biopsy improves prostate cancer diagnosis
Prostate biopsy using the multiparametric MRI/ultrasound fusion-guided (mpMRI/US) technique improves prostate cancer diagnosis and reduces the detection of clinically insignificant cancers, according to data presented the 15th Urological Association of Asia Congress (UAA 2017) held recently in Hong Kong.
In a study conducted at the Queen Mary Hospital (QMH), Hong Kong, the mpMRI/US technique was associated with a significantly higher overall prostate cancer detection rate compared with conventional 12-core biopsy (37.3 vs 17.6 percent; p<0.0001).
“The mpMRI/US technique also resulted in more clinically significant prostate cancers being detected [23.5 percent vs 10.4 percent for 12-core biopsy], longer cancer tissue core lengths being obtained [5.1 vs 3.6 mm], and more importantly, reduced detection of clinically insignificant cancers,” reported lead author Dr Wai-Kit Ma of the Department of Surgery, The University of Hong Kong.
The study compared the diagnostic efficacy and complication outcome of 102 Chinese patients with Prostate Imaging – Reporting and Data System Version 2 (PI-RADS) 2–5 lesions of the prostate who underwent transrectal targeted biopsy plus 12-core biopsy using the semirobotic Artemis MRI/US fusion platform system (one of the two machines available in Asia), with a matched cohort of 250 patients who underwent conventional transrectal ultrasound (TRUS)-guided 12-core biopsy alone. [Asian J Androl 2017;19:1-2]
“While TRUS-guided biopsy is the current standard for prostate cancer diagnosis, it is a ‘blind’ procedure that misses up to 35 percent of clinically significant cancers. It is also reported to overdiagnose clinically insignificant cancers,” said Ma.
“There is indeed very good potential in saving patients from undergoing unnecessary biopsies as our study affirmed that PI-RADS score correlated well with cancer incidence,” said Ma. “None of the patients with a PI-RADS score of 2 were detected for cancer, while detection rates for those with PI-RADS scores of 3, 4 and 5 were 10 percent, 30.4 percent and 100 percent, respectively. Among those detected with cancer, a relatively high proportion of clinically significant cancers were detected [8.2 percent, 25 percent and 88.9 percent for PI-RADS scores of 3, 4 and 5, respectively].”
“Complication rates were low with the mpMRI/US technique, with postprocedural haematuria and sepsis occurring in 3.1 and 0.6 percent of patients vs 14 and 3.2 percent with conventional 12-core biopsy,” Ma reported. “The accuracy of the tracking mechanism, which allows very precise location of the lesion and the biopsy tract, minimizes the risk of puncture of the capsule or the urethra.”
“Our results concur with the few studies done in the region, such as the recent multicentre study on transperineal MRI/US fusion biopsy using the novel device iSR’obot Mona Lisa, as well as earlier studies done in the West,” he noted. [J Urol 2013;189:86-92; Int Urol Nephrol 2015;47:727-733; BMC Urol 2017;17:52; Eur Urol Suppl 2017;16:e2092-e2093]
“Further studies are needed to evaluate the cost-effectiveness of adopting fusion prostate biopsy as the standard of prostate cancer diagnosis in Asia, and whether it could be used in the initial biopsy setting instead of in previously-negative biopsies only, due to limited healthcare resources and experienced radiologists in our region, and the significant financial implications if biopsies were to be done on the majority of patients,” Ma concluded.