PSMA PET-CT Versus Conventional Imaging for Aggressive Prostate Cancer
Posted: Monday, June 29, 2020
Prostate-specific membrane antigen (PSMA) PET-CT imaging appears to detect high-risk prostate cancers with a 27% greater accuracy than conventional CT and bone scans, according to Michael S. Hofman, MBBS, of Peter MacCallum Cancer Centre, Melbourne, and colleagues. The authors of this study, which was published in The Lancet, recommended this molecular imaging be incorporated into clinical practice to ensure proper diagnosis of men with aggressive prostate cancers.
“[Relapse after surgery or radiotherapy occurs] partly because current medical imaging techniques often fail to detect when the cancer has spread, which means some men are not given the additional treatments they need,” senior author Declan G. Murphy, MBBCh, commented in a press release. “Our findings suggest PSMA PET-CT could help identify these men sooner, so they get the most appropriate care.”
Briefly, PSMA PET-CT imaging employs PSMA-targeted radiotracers, followed by PET/CT scanning. A total of 300 patients with histologically confirmed high-risk prostate cancer underwent first-line imaging procedures. To be enrolled, patients were required to have a prostate-specific antigen (PSA) concentration of at least 20 ng/mL, International Society of Uropathology grade group 3 to 5, or a tumor of clinical stage T3 or worse. The patients were randomly assigned to receive either PSMA PET-CT or conventional CT and bone scan as first-line imaging. After 14 days, 291 patients underwent second-line scans using the alternative imaging arm.
Conventional imaging demonstrated lower sensitivity (38% vs. 85%) and specificity (91% vs. 98%) than PSMA PET-CT imaging. PSMA PET-CT was also superior to conventional imaging for patients with distant metastases (AUC = 95% vs. 74%) and for patients with pelvic nodal metastases (AUC = 91% vs. 59%). Treatment plans were changed for 27% of patients who received second-line PSMA PET-CT imaging. However, second-line conventional imaging resulted in a change of treatment plan for just 5% of patients. Of note, conventional imaging exposed patients to significantly higher amounts of radiation (P < .001).
Disclosure: For full disclosures of the study authors, visit www.thelancet.com.