Editorial Comment: 68Ga-Prostate-specific membrane antigen (PSMA) positron emission tomography (pet) in prostate cancer: a systematic review and meta-analysis

Abstract

Matushita and colleagues performed a comprehensive review and meta-analysis about the role of 68 Ga PSMA PET in the diagnostic and in re staging of prostate cancer based on the final selection of 35 studies with more than 3900 patients in this issue publication: Ga-Prostate-specific membrane antigen (psma) positron emission tomography (pet) in prostate cancer: a systematic review and meta--analysis (1). The evaluated series were heterogeneous, since the review encompassed, as patients submitted to prostate biopsy (diagnostic), as patients underwent radical prostatectomy, radiotherapy or lymphadenectomy, and some series including MRI in combination with 68 GA PSMA PET, also.The use of ASTRO 1996 definition in this review, seems at first sight an interesting choice, since the lower PSA cut-off for relapse (three consecutives PSA elevations >0.2 ng/mL), when compared with Phoenix Definition (nadir plus 2.0 ng/mL), could result, in early anatomic diagnostics of the recurrence sites by this nuclear scan, which could result in early precise salvage treatments. However, an ASTRO consensus, in 2006, has recommend by the limitation use of ASTRO definition only for patients undergone exclusive external beam radiotherapy, since this failure definition perform poorly in patients which received hormonal therapy (2).The review manuscript corroborated the high sensitivity and positivity from 68 Ga PSMA at diagnostic. It is really interesting mainly in when focal therapy is planned, being as tool option for exclusion of some non-diagnosticated contralateral lesion after an anatomopathological test revealing only unilateral cancer.On the other hand, for bilateral tumors, evolving the whole gland, in the era of fusion biopsy, probably 68 Ga PSMA PET might be less ordered, because in this moment, anatomopathological tests must not be excluded or replaced by functional image methods. In this scenario, perhaps patients with high suspicion for prostate malignancies with previous negative biopsies, can be benefited by the use of 68 Ga PSMA (combined or not with MRI).A great daily clinical practice challenge, is the re-staging of recurrent prostate cancer, with was well discussed in the paper. We must reinforce that authors shown that in the biochemical recurrence studies, a quarter of cases, the 68 Ga PET CT are negatives. Although it could sound unfavorable, in a