‘Superior’ detection of biochemical recurrence with PSMA PET–CT
medwireNews: 68Ga-prostate-specific membrane antigen (PSMA)-11 should be the “tracer of choice” for positron emission tomography–computed tomography (PET–CT) to detect the postoperative biochemical recurrence of prostate cancer, say researchers who conducted a comparative imaging trial.
As reported in The Lancet Oncology, the primary endpoint of the biochemical recurrence detection rate was significantly higher with PSMA PET–CT than with 18F-fluciclovine PET–CT, at 56% versus 26%, equating to a patient-level odds ratio (OR) of 4.8 in favor of PSMA PET–CT.
The study authors explain that 18F-fluciclovine is the tracer recommended by the US National Comprehensive Cancer Network, while the European Association of Urology guidelines support the use of PSMA.
They add that in light of the “superior detection rates” with PSMA PET–CT, this “should become the standard of care” in men with biochemical recurrence and low serum levels of prostate-specific antigen (PSA).
Specifically, the 50 trial participants had PSA levels ranging from 0.2 to 2.0 ng/mL following radical prostatectomy, and all underwent paired PSMA and 18F-fluciclovine PET–CT imaging within a maximum of 15 days of each other.
PSMA PET–CT also proved to be significantly better than 18F-fluciclovine PET–CT for the detection of recurrence in the pelvic lymph node region (30 vs 8%) and for extrapelvic lesions (16 vs 0%); the respective ORs were 12.0 and inestimable.
Jeremie Calais (University of California Los Angeles, USA) and co-authors acknowledge, however, that they were unable to determine the sensitivity and specificity of the imaging techniques as PET–CT findings were validated by a reference standard in less than a third of the participants.
They write that “[l]arger cohorts would be required to formally address this question.”
The researchers also highlight the need for additional research “to investigate whether higher detection rates translate into improved oncological outcomes,” noting that this is being addressed in several ongoing phase III randomized clinical trials.
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