PSMA PET/CT may replace need for prostate biopsy in staging older patients

Recent findings indicate that prostate-specific membrane antigen (PSMA) PET/CT can sufficiently detect advanced prostate cancer and guide therapeutic approach, suggesting that older patients with prostate cancer may be able to avoid pre-imaging biopsy and undergo staging with PET/CT alone.^1,2

Referral for hormonal therapy was similar between patients who underwent biopsy compared with those who did not.

“Due to the risks of biopsy for elderly patients, they are occasionally referred for PSMA PET/CT without a pre-imaging confirming biopsy. In our study we sought to determine the rate, clinical characteristics, and PET-based stage of elderly patients referred for PSMA PET/CT without biopsy and explore whether their biopsy status affected therapeutic approach,” said senior author Einat Even-Sapir, MD, PhD, in a news release on the findings.² Even-Sapir is the head of the department of nuclear medicine at Tel Aviv Sourasky Medical Center and professor of imaging at Tel Aviv University in Tel Aviv, Israel.

In total, 100 patients aged 80 and older were included in the study. Each patient underwent primary staging with 68Ga-PSMA-11 PET/CT between January 2016 and September 2021.

Data showed that among all participants, 34% had no pre-imaging biopsy conducted. Patients who did not undergo pre-imaging biopsy were more likely to be older (P < .01), have worse clinical status (P < .01), and have higher PSA levels (P < .01) compared with those who underwent biopsy.

All patients who did not undergo biopsy were found to have avid disease on 68Ga-PSMA-11 PET/CT. Data showed that 47.1% of those who did not undergo biopsy were found to have bone metastases, compared with 28.8% of those who received pre-imaging biopsy. Further, advanced disease was found among 50% of patients who did not undergo biopsy vs 33.3% in patients who underwent biopsy.

Referral for hormonal therapy was similar between patients who underwent biopsy compared with those who did not (81.8% versus 73.5%, respectively, P = .34). Conversely, 63% of patients who underwent biopsy were referred for radiotherapy, compared with only 8.8% of patients who did not receive pre-imaging biopsy (P < .01).

Further, patients who did not undergo biopsy and had localized (n = 36) or locally advanced disease (n = 25) were less likely to be referred for definitive therapies compared with patients who did undergo biopsy (P < .01). Those who were not referred for definitive therapies were more likely to be older, have worst performance status, or have a higher PSA level.

Even-Sapir concluded in the news release,² “The results of the current study indicate that 100% of the elderly patients who were referred for PSMA PET/CT 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 elderly patients, the practice of waiving the need for pre-imaging biopsy when the clinical suspicion is high proves to be effective and to have no apparent negative cost.”

The authors indicate that larger studies are still needed to validate their findings.

References

1. Kesler M, Cohen D, Levine C, Sarid D, Keisman D, Yossepowitch O, Even-Sapir E. Staging prostate cancer with 68Ga-PSMA-11 PET/CT in the elderly: Is preimaging biopsy imperative?. J Nucl Med. 2023;64(7):1030-1035. doi:10.2967/jnumed.122.265371

2. PSMA PET/CT waives the need for pre-imaging biopsy in elderly patients. News release. Society of Nuclear Medicine & Molecular Imaging. August 14, 2023. Accessed August 15, 2023. http://www.snmmi.org/NewsPublications/NewsDetail.aspx?ItemNumber=44455