Positive results on PSMA PET/CT scans predict more aggressive disease progression in men with prostate cancer (PCa) who experience biochemical recurrence (BCR) after radical prostatectomy (RP), according to investigators presenting at the European Association of Urology 2020 virtual congress.
Of 113 patients who received a gallium-68 positron emission tomography-computed tomography scan (68Ga-PSMA PET/CT) at the onset of BCR (median 24 months after RP; 2 PSA values of 0.2 ng/mL or higher), 67 had a positive and 48 had a negative scan result. PSA at the time of the PSMA PET/CT scan (median 0.6 ng/mL) was the sole significant predictor of positive findings.
The group with positive scans were treated more aggressively after PSMA PET/CT, with 51%, 57%, and 21% of the positive-scan group group undergoing salvage radiation therapy, salvage hormone therapy, and salvage lymph node dissection compared with 30%, 26%, and 2% of the negative-scan group, respectively. The 2-year progression-free survival rate was significantly lower for the group with a positive scan at BCR: 65% vs 95%, Daniele Robesti, MD, of IRCCS Ospedale San Raffaele, Milan, Italy, reported. On multivariable analyses, a positive PSMA PET/CT scan was significantly associated with a 4.5-fold higher adjusted risk for disease progression than a negative scan, he highlighted.
According to Dr Robesti’s team, a positive 68Ga-PSMA PET/CT scan predicts disease progression, whereas a negative scan indicates a low likelihood of progression at 2 years of follow-up, even in the absence of salvage therapies.
“This indirectly supports the use of intense salvage approaches for men with positive PSMA PET/CT given the high risk of disease progression,” they concluded during a webcast.
Overall, 41% of patients had grade group 4 to 5 and 24% had pN1 disease at RP. Half of patients received RT and 29% androgen deprivation therapy before PSMA PET/CT. At a median follow-up of 18 months after imaging, 23% of patients experienced disease progression.
Robesti D, Gandaglia G, Fossati N, et al. A positive PSMA PET/CT predicts more aggressive disease progression in patients with biochemical recurrence after radical prostatectomy [webcast]. Presented at: EAU20 Virtual Congress; July 17 to 19, 2020. Poster PT028.