Prostate-specific membrane antigen positron-emission tomography/computed tomography (PSMA PET/CT) imaging may help physicians diagnose advanced disease and select the appropriate therapeutic interventions in patients aged 80 years or older with suspected prostate cancer, according to a recent study published by Kesler et al in The Journal of Nuclear Medicine. The new findings demonstrate that PSMA PET/CT imaging can potentially reduce the number of prostate biopsies and associated complications in older patients while providing accurate staging data.
Background
Gallium (Ga)-68–PSMA-11 PET/CT imaging has gained acceptance as a highly sensitive and specific imaging modality for evaluating the extent of disease in patients with prostate cancer. In general, PSMA PET/CT imaging is indicated for patients whose biopsies have been positive for intermediate- or high-risk cancer. In older patients, however, prostate biopsies may be associated with longer hospital stays and postbiopsy complications such as infections, bleeding, and urinary retention.
“[As a result of] the risks of biopsy, … [older] patients … are occasionally referred for PSMA PET/CT [imaging] without a preimaging confirming biopsy,” explained senior study author Einat Even-Sapir, MD, PhD, Professor of Imaging at Tel Aviv University and Head of the Department of Nuclear Medicine at the Tel Aviv Sourasky Medical Center. “In our study, we sought to determine the rate, clinical characteristics, and PET-based stage of [older] patients referred for PSMA PET/CT [imaging] without biopsy—and explore whether their biopsy status affected therapeutic approach,” she added.
Study Methods and Results
In the new study, investigators involved 100 patients aged 80 years or older who underwent staging with Ga-68–PSMA-11 PET/CT imaging. The investigators then documented whether preimaging biopsies were performed, the clinical characteristics, the PET-based staging parameters, and the primary therapy the patients received.
The investigators found that 34% of the patients involved in the study had not received preimaging biopsies. Compared with those who did receive preimaging biopsies, patients who forwent the biopsies tended to be older, with worse clinical status, and higher prostate-specific antigen levels. Further, all of the patients who didn’t receive preimaging biopsies were shown to have avid disease after Ga-68–PSMA-11 PET/CT imaging, with trends toward higher rates of bone metastases and overall advanced disease. Similar proportions of patients with and without preimaging biopsies were referred for hormonal therapy. In contrast, 63% of the patients who received biopsies were referred for radiotherapy after imaging vs only 8.8% of the patients who didn’t receive preimaging biopsies.
Conclusions
“The results of the current study indicate that 100% of the [older] patients who were referred for PSMA PET/CT [imaging] on the basis of clinical suspicion only were found to have avid disease. Given that positive PSMA PET/CT results usually indicate clinically significant rather than clinically insignificant prostate cancer—and together with the insignificant negative effect of radiation exposure in [older] patients—the practice of waiving the need for preimaging biopsies when the clinical suspicion is high proves to be effective and to have no apparent negative cost,” concluded Dr. Even-Sapir.
Disclosure: For full disclosures of the study authors, visit jnm.snmjournals.org.
