Assessment of 68Ga-PSMA-11 PET positivity predictive factors in prostate cancer.

Abstract

Positron emission tomography (PET) studies with 68Ga-PSMA-11 (68Ga-HBED-CC-PSMA) have earned the attention of researchers, due to overexpression of PSMA in the tumoral tissues of prostate cancer. Our aim was to analyse the potential benefit of this radiotracer in the biochemical relapse of prostate cancer. This retrospective analysis included 53 studies, performed on 50 male prostate cancer patients referred due to biochemical recurrence. In all cases, previous imaging techniques were negative or inconclusive. Of the 53 studies, 36 (68%) were positive. Significant differences were found between the positive and negative PET groups in Gleason's scale, PSA levels, PSAdt, late acquisition and the administration of androgen deprivation therapy during treatment (P<.05). Regarding PSA levels, 10 (48%) of the 21 patients with PSA<1ng/ml, obtained a pathological PET result. When the PSAdt was below six months, 86.7% of the patients obtained an abnormal PET. In the multivariate analysis, only Gleason's scale was associated independently with an abnormal PET result. 68Ga-PSMA-11 PET shows a high disease detection rate in patients where other techniques showed negative or doubtful images. Almost 50% of patients with prostate cancer biochemical recurrence and low PSA levels (<1ng/ml) have active disease on 68Ga-PSMA-11 PET, precisely where other radiotracers lack sensitivity.