In patients with a high suspicion of prostate cancer as determined by molecular imaging, avoiding biopsy prior to radical prostatectomy appeared to be feasible, and “might represent a valid option in well-counseled, selected patients,” according to German researchers.

In a case series of 25 men who underwent primary radical prostatectomy without prior biopsy after an imaging-based diagnosis via multiparametric MRI and prostate-specific membrane antigen PET (PSMA-PET), diagnoses of significant prostate cancers were confirmed on postoperative histopathology, with all patients showing International Society of Urological Pathology (ISUP) grade ≥2 prostate cancer (n=8 with ISUP grade 2; n=15/25 ISUP grade 3; n=2 ISUP grade), according to Valentin H. Meissner, MD, of the Technical University of Munich, and colleagues.

“Results illustrate the need for a prospective evaluation within an ethically approved clinical trial, and have the aim to promote a debate on this approach and about our demands for biopsies in the future,” they wrote in European Urology.

Imaging results were considered highly suspicious for prostate cancer if indicated by both MRI (Prostate Imaging Reporting and Data System [PI-RADS] score ≥4) and PSMA-PET (PET score ≥4 on a five-point Likert scale and maximum standardized uptake value ≥4.0).

On a per-patient basis, sensitivity and positive predictive value for both MRI and PSMA-PET in identifying significant prostate cancer were 100% and 100%, respectively.

Four patients had seminal vesicle invasion, six patients had extracapsular extension (ECE), and the remaining 15 patients had organ-confined disease. Lymph node invasion was found in four patients in the final pathology. PSMA-PET correctly identified one of these patients preoperatively.

The cases consisted of men with a median age 70.9 at surgery. Most of the surgeries were done in 2018 (40%). The median PSA at diagnosis was 7.3.

Suspicion of significant prostate cancer in each of the case-series patients was raised by their treating urologist based on elevated PSA and/or a digital rectal examination. After completion of both MRI and PSMA-PET, patients were informed about their high risk of prostate cancer and counseled by their treating urologist.

“All patients presented at our department with the pre-existing and explicit wish to undergo RP [radical prostatectomy] without prior biopsy based on existing imaging results including PSMA PET and mpMRI [multiparametric MRI],” Meissner’s group pointed out. Subsequently, patients were counseled about the risk of false-positive imaging results, the necessity of performing a prostate biopsy for histopathologic confirmation, as well as other possible treatment options, including active surveillance, radiotherapy, and focal therapies.

“Especially, the risk of finding ‘no cancer’ at the radical prostatectomy specimen was discussed and explained to the patient,” the authors reported. “Nonetheless, every patient wished explicitly an RP without prior biopsy despite the recommendation to perform a prior prostate biopsy according to current guidelines.”

The authors reported that both MRI and PSMA-PET correctly identified seminal vesicle invasion in all four (100%) patients, ECE in four of the six (67%) patients and locally confined disease in 13 (52%) patients, while two (8.0%) patients suspicious for ECE in MRI and PSMA-PET showed locally confined disease and two (8.0%) patients suspicious for locally confined disease showed ECE on histopathology.

In an accompanying editorial, Parth K. Modi, MD, MS, and Scott E. Eggener, MD, both of the University of Chicago, conceded that for many clinicians, the gut response to opting for prostatectomy without prior biopsy “will understandably be shock and scorn. For us, the concept is discomfiting but provocative. After digestion of the data, the strategy has become more intriguing. While it remains surprising that any man would opt for prostatectomy to forego the potential morbidity of a biopsy, the authors affirm that the patients were counseled extensively and proceeded with appropriate informed consent.”

Meissner and colleagues identified several possible benefits associated with proceeding to prostatectomy without biopsy:

• No further complications after biopsies
• Reduced time from diagnosis to treatment
• A lower psychological burden, and less anxiety in patients
• Lower health economic costs (i.e., comparing the cost of an additional PSMA-PET exam versus the cost of unnecessary biopsies)

However, Modi and Eggener suggested there is a “high bar” to be met in relying on imaging for diagnosis. For example, they noted that high-volume cohorts from experienced centers have shown PSMA-PET is imperfect in identifying clinically significant prostate cancer within the prostate. They also pointed that high-quality imaging tests such as PSMA-PET and MRI may be prohibitively expensive.

Modi and Eggener also observed that potential benefits of avoiding biopsy must be weighed against the risks associated with proceeding to prostatectomy — including the possibility of unnecessary surgery, and potential complications and side effects.

“Ultimately, we recognize that the potential morbidity of prostatectomy is the exact reason why the paradigm discussed warrants pause, critical analysis, and extensive validation before implementation outside of a clinical trial,” they wrote. “As we continue to work to improve the care for men with prostate cancer, we should remain open-minded about potential new advances but steadfast in demanding rigorous evaluation of these ideas before their widespread adoption.”

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