Detection of circulating tumor cells and PTEN loss in localized prostate cancer before and after radical prostatectomy: Prognostic implications and predictors of treatment response.

e17125 Background: There is a lack of reliable biomarkers to predict the recurrence of prostate cancer following prostatectomy, which can better guide surgical treatment decisions and post-operative management strategies. Loss of PTEN (Phosphatase and Tensin Homolog) is recognized as a marker of poor prognosis in prostate cancer. Additionally, the clinical significance of circulating tumor cells (CTCs) in early-stage disease remains controversial. In this context, we aimed to evaluate the pre- and post-operative detection of CTCs, along with the status of PTEN loss, in a cohort of prostate cancer patients from the Amazon region. Methods: We prospectively identified fifty patients with localized prostate adenocarcinoma who chose prostatectomy as their definitive treatment. Inclusion criteria included confirmed prostate adenocarcinoma localized disease, with no prior treatment. Exclusion criteria encompassed confirmed metastatic disease via bone scan and prior hormonal therapy. Blood samples (7.5 mL each) were collected two days before surgery and 30 days post-operatively. CTCs were isolated using the CellSearch platform, defined as nucleated cells that stained positive for cytokeratin (CK) and negative for CD45. PTEN deletions were analyzed through fluorescence in situ hybridization (FISH). Statistical analyses were performed using RStudio, with a significance level of p < 0.05 and the non-parametric Wilcoxon test applied for comparative analyses. Results: Among the 50 patients with localized prostate cancer, loss of phosphatase and tensin homolog (PTEN) was identified in 6 patients (12%), all of whom had a clinical International Society of Urological Pathology (ISUP) grade of 2 or higher. Circulating tumor cells (CTCs) were detected in all 50 patients (100%) prior to surgery, with counts ranging from 3 to 6 CTCs per patient. Post-surgery, there was a significant reduction in CTC counts, with 88% of patients (n=44) showing a count of zero CTCs. This reduction yielded a p-value of < 0.001. Conclusions: Our results suggest that the detection of circulating tumor cells (CTCs) before and after surgery serves as a valuable predictive marker for the response to initial therapy and may indicate the risk of cancer recurrence in patients with non-metastatic prostate cancer (PCa). Furthermore, the loss of phosphatase and tensin homolog (PTEN) appears to be an early event in the progression of prostate cancer.