Enhancing PSMA-uptake with androgen deprivation therapy - a new way to detect prostate cancer metastases?

ABSTRACT Purpose: 68Ga-PSMA PET/CT imaging is a promising modality for the staging of recurrent prostate cancer (PCa). Current evidence suggests limited diagnostic value of the 68Ga-PSMA PET/CT in PSA-levels ≤0.3ng/mL. Experimental data have demonstrated an increase in PSMA-expression in PCa metastases by androgen deprivation in vitro. The aim of the current study was to investigate a possible enhancing effect of PSMA with low-dose androgen deprivation in patients with BCR and low PSA-levels. Materials and Methods: Five patients with PCa and BCR, following radical prostatectomy, underwent 68Ga-PSMA PET/CT. A consecutive 68Ga-PSMA PET/CT was performed 6 to 11 days after injection of 80mg of Degarelix (Firmagon®). We recorded PSA and testosterone serum-levels and changes of PSMA-uptake in 68Ga-PSMA PET/CT images. Results: Median PSA prior 68Ga-PSMA PET/CT was 0.27ng/mL. All patients had a decrease in testosterone serum levels from median 2.95μg/l to 0.16μg/l following Degarelix injection. We observed an increase in the standardized uptake value (SUV) in PSMA-positive lymphogenous and osseous lesions in two patients following androgen deprivation. In another two patients, no PSMA positive signals were detected in either the first or the second scan. Conclusion: Our preliminary results of this feasibility assessment indicate a possible enhancing effect of PSMA-imaging induced by low-dose ADT. Despite several limitations and the small number of patients, this could be a new approach to improve staging by 68Ga-PSMA PET/CT in PCa patients with BCR after primary therapy. Further prospective studies with larger number of patients are needed to validate our findings.

Long-term clinical outcome in patients with stage-i nonseminomatous germ cell cancer: a critical review of own treatment modalities in a retrospective study

PURPOSE: The optimal management of patients with clinical stage I non-seminomatous germ cell testicular cancer (NSGCT I) was considered controversial until the European Germ Cell Cancer Consensus Group determined unambiguous treatment strategies. In order to assess the long-term outcome we evaluated the data of patients with NSGCT I. MATERIALS AND METHODS: In a retrospective evaluation, we included 52 patients with a mean age of 26 years (range 15-58) who were treated with different modalities at our department between 1989 and 2003. Mean follow-up was 5.9 years (range 2-14 years). After orchiectomy, 39 patients were treated with chemotherapy, 7 patients underwent retroperitoneal lymph node dissection and 6 men were managed using a surveillance strategy. Survival, recurrence rate and time of recurrence were evaluated. The histological staging and treatment modality was related to the relapse. RESULTS: Tumor specific overall mortality was 3.8 percent. The mortality and relapse rate of the surveillance strategy, retroperitoneal lymph node dissection and chemotherapy was 16.7 percent / 50 percent, 14.3 percent / 14.3 percent and 0 percent / 2.5 percent respectively. All relapsed patients in the surveillance group as well as in the RPLND group had at least one risk factor for developing metastatic disease. CONCLUSIONS: Following the European consensus on diagnosis and treatment of germ cell cancer in patients with NSGCT Stage I any treatment decision must be individually related to the patient according to prognostic factors and care capacity of the treating centre. In case of doubt, adjuvant chemotherapy should be the treatment of choice, as it provides the lowest risk of relapse or tumor related death.