In a prospective single-arm clinical trial, 68Ga-PSMA-11 positron emission tomographic (PET) imaging showed high positive predictive value (PPV), detection rate, and interreader agreement for localization of recurrent prostate cancer. 635 men (median age 69 years) with biochemically recurrent prostate cancer after prostatectomy (n=262; 41%), radiation therapy (n=169; 27%), or both (n=204; 32%) underwent 68Ga-PSMA-11 PET. Presence of prostate cancer was recorded by 3 blinded readers on a per-patient and per-region base. Endpoints were PPV, detection rate, interreader reproducibility, and safety. Researchers found:
- 68Ga-PSMA-11 PET demonstrated 84% to 92% positive predictive value at 75% overall detection rate in patients with biochemically recurrent prostate cancer and median prostate-specific antigen of 2.1 ng/mL.
- Interreader reproducibility was substantial.
- There were no serious adverse events associated with 68Ga-PSMA-11 PET administration.
Fendler WP, Calais J, Eiber M, et al. Assessment of 68Ga-PSMA-11 PET accuracy in localizing recurrent prostate cancer: A prospective single-arm clinical trial. [Published online ahead of print March 28, 2019]. JAMA Oncol. doi:10.1001/jamaoncol.2019.0096.
True detection of the extent of prostate cancer is an ongoing challenge. Many current clinical studies will utilize a mix of CT and bone scan imaging to determine progression of disease in addition to PSA. A single imaging modality with a higher sensitivity and specificity than current imaging is clearly needed. The study by Fendler et al. reveals compelling results and good progress towards this goal. Results from studies comparing Fluciclovine F18 PET/CT versus 68Ga-PSMA-11 PET/CT need to mature before more definitive decisions on which imaging modality and accompanying agent should be utilized in prostate cancer patients. —Mark A. Klein, MD