Reply to Thorsten Derlin, Matthias Eiber, Markus Schwaiger, and Frank M. Bengel's Letter to the Editor re: Lars Budäus, Sami-Ramzi Leyh-Bannurah, Georg Salomon, et al. Initial Experience of 68Ga-PSMA PET/CT Imaging in High-risk Prostate Cancer Patients Prior to Radical Prostatectomy. Eur Urol 2016;69:393–6

Autor: Thomas Steuber, Sami-Ramzi Leyh-Bannurah, Lars Budäus
Rok vydání: 2016
Předmět:
Zdroj: European Urology. 70:e39-e40
ISSN: 0302-2838
DOI: 10.1016/j.eururo.2015.07.056
Popis: When evaluating a new imaging modality, it is mandatory to consider some complex aspects which play a pivotal role in prostate cancer imaging. Firstly, the true (ie, histology proven) incidence of lymph node metastases influences the results of every validation study. Specifically, the inclusion of low and intermediate risk patients, in whom lymph node metastases are rare, automatically improves the accuracy of the analyses. To circumvent this bias, we excluded 28 low and intermediate risk patients in our study [1]. Secondly, using histologic specimens postsurgery is the gold standard for analyzing the performance of an imaging modality. Moreover, as stated in our article, Ga-prostatespecific membrane antigen (PSMA)-positron emission tomography (PET)/computed tomography were performed and analyzed in experienced imaging centers. More importantly, we are recently in the challenging situation that PSMA-imaging is already broadly established in clinical practice: Patients and surgeons rely on the final PSMA-PET report, althoughtheevidence forPSMA-imaging is predominantly based on heterogeneous patient cohorts in which histologic work up was not performed on a regular basis (eg, recurrence after radiation therapy vs prior radical prostatectomy) [2]. Interestingly, Dr. Derlin and colleagues referenced such series, comprising heterogeneous patients with biochemical recurrence or progressive disease. Moreover, the majority of these patients already underwent radical prostatectomy and the prostate was present in the remaining 10.8% (4/37) of patients. Therefore, we have concerns that these results would be applicable to patients prior to radical prostatectomy and would be suited to refute the hypothesis that presence of the primary prostate influences lymph node metastases detection by tracer depletion. Similarly, missing the PSMA signal of the primary intraprostatic tumor has been reported in a small proportion
Databáze: OpenAIRE
Externí odkaz: