Transperineal targeted biopsy (TB) with fewer systematic biopsy (SB) cores may have a comparable prostate cancer (PCa) detection rate as the recommended TB+SB approach, according to a new study.

The optimal prostate sampling scheme for limiting the incidence of biopsy complications while still achieving the highest diagnostic accuracy remains controversial. Studies have documented that complications such as infection, hemorrhage, hematuria, erectile dysfunction (ED), and acute urinary retention increase with the rising number of biopsy cores. The new study, by Hua Liu, MD, of Peking University First Hospital in Beijing, China, and colleagues prospectively compared the detection rates for PCa overall and clinically significant PCa (csPCa) with different sampling schemes in 165 men with suspicious lesions identified by magnetic resonance imaging (MRI). The investigators defined csPCa as a Gleason Score (GS) of 7 or higher. They performed transperineal TB and SB (TB+SB) for each patient as a reference. Dr Liu and colleagues compared 3 hypothetical biopsy sampling schemes: TB only, SB only, and TB followed by SB of the nontargeted sector (TB+nSB).

Of the 165 patients, 107 (64.8%) were diagnosed with PCa and 91 (55.2%) were diagnosed with csPCa via TB+SB. There were 54 (50.5%) and 42 (46.2%) MRI true-negative cases and 53 (49.5%) and 49 (53.8%) false-negative cases of nontargeted sectors among patients with PCa and csPCa, respectively, the investigators reported in Prostate Cancer and Prostatic Diseases. The number of patients diagnosed with csPCa was 91 (100%) by TB+SB, 89 (97.8%) by TB+nSB, 78 (85.7%) by SB alone, and 84 (92.3%) by TB alone. The PCa and csPCa detection rates between standard TB+SB with MRI/ultrasound fusion biopsy and TB+nSB did not differ significantly, the investigators reported.

The proportions of false-negative MRI results for men with PCa and those with csPCa suggests “that SB of the non-targeted sector is necessary and cannot be omitted,” the authors stated.


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Rosaleen B. Parsons, MD, chair of diagnostic imaging at Fox Chase Cancer Center in Philadephia, said the findings must be viewed cautiously because the authors did not provide information about gland size. Larger glands can be more difficult to biopsy, which could impact these results, Dr Parsons explained. About 30 % of PCa tumors occur in the transitional zone, an area known to be difficult to assess with prostate MRI because of underlying prostatic hypertrophy. “Benign and suspicious features frequently overlap,” Dr Parsons said. “The authors do not report how many lesions were in the transitional zone. Specifically the percentage of false positives in this area would have been interesting to review.”

She pointed out that the authors performed biopsies using MRI-ultrasound fusion software in 62% of cases. Subsequently, 38% of the biopsies were not performed with fusion software, and this could result in “missing the lesion.” This may be of particular concern for transitional zone and anterior lesions. “I think it is important to look at this issue to decrease patient morbidity and mortality by potentially reducing the number of biopsies. However, I do not believe the authors’ data support limiting the number of biopsies.” Dr Parsons said.

“It would certainly make both urologists and patients happier if we could decrease the number of biopsies and still have the same rate of detection of clinically significant prostate cancer,” said Michelle Yu, MD, a urologic oncology fellow and clinical instructor at the fellow and clinical instructor at University of Pittsburgh Medical Center in Pittsburgh, Pennsylvania. MRI can miss a portion of csPCa, so many urologists will do a standard 12-core biopsy in addition to the targeted biopsy. The authors of the new study provide evidence that only a targeted biopsy with a contralateral standard biopsy are necessary to identify clinically significant cancers, she noted.

“Many groups have attempted to study how to use MRI-detected lesions to alter the sampling scheme from the traditional 12-core sextant biopsy to reduce biopsy complications,” Dr Yu said. “There is still no consensus on where to biopsy or how many biopsies. We need to look at whether certain locations of MRI lesions are associated with different sampling requirements.”

Daniel I. Lee, MD, chief of urology and vice chief of surgery at Penn Presbyterian Medical Center and associate professor of urology in surgery at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, said the new study makes an important contribution, but is limited by its design. “It is not randomized, so that can introduce bias,” Dr Lee said.

The study does not really answer whether fewer needle biopsies provide a significant benefit, he said. “It would be nice easy to see a cost-effective analyses for transperineal biopsy,” Dr Lee said. “It takes longer and requires additional setup. So, it does add to costs. It would be nice to know what the differences are with costs. We are always looking for new and better ways of improving diagnosis.”

Reference

Liu H, Ruan M, Wang H, et al. Can fewer transperineal systematic biopsy cores have the same prostate cancer detection rate as of magnetic resonance imaging/ultrasound fusion biopsy? Prostate Cancer Prostatic Dis. Published online July 27, 2020. doi:10.1038/s41391-020-0260-0