The presence of secondary circulating prostate tumour cells determines the risk of biochemical relapse for patients with low- and intermediate-risk prostate cancer who are treated only with external radiotherapy

Abstract

IntroductionThe classification of patients with prostate cancer is used to determine treatments based on risk factors. The presence of secondary circulating prostate tumour cells (CPCs) detected in peripheral blood after a curative treatment has been associated with a worse prognosis. We present a prospective study of CPC detection post radiotherapy and the oncological results.Patients and methodsAll of the patients classified as low and intermediate risk that were treated with radiotherapy were included. Three months after finishing treatment, an 8-ml blood sample was taken to detect CPCs. Mononuclear cells were obtained using gel centrifugation, and CPCs were identified using immunocytochemistry with anti-prostate-specific antigen. Patients were classified as low-risk CPC positive or negative and intermediate-risk CPC positive or negative. The biochemical relapse-free survival analysis was determined based on a follow-up of up to 15 years using the Kaplan–Meier and Cox regression models. Biochemical failure was defined according to the Pheonix II criteria.ResultsOf 241 patients, 181 (75.1%) were classified as low risk and 60 (24.9%) as intermediate risk. Biochemical failure was observed in 27.1% (49/181) of the low-risk prostate cancer participants and in 53.3% (32/60) of intermediate-risk participants after 15 years of follow-up. 20.4% (37/181) of the low-risk cancer participants had detectable CPCs in comparison with 43.3% (26/60) of the intermediate-risk cancer participants (p < 0.001 overall risk 2.98, confidence interval (CI) 95% 1.59–5.56; relative risk 2.12, CI 95% 1.41–3.19). Positive CPC patients had a worse prognosis, and a shorter time period until biochemical relapse, regardless of risk group. The biochemical relapse-free survival curves show that intermediate-risk participants who were CPC negative had a higher survival rate and slower disease progression than those participants who were low risk but CPC positive.ConclusionsCPC detection is a risk factor for biochemical relapse and could be useful in identifying patients that will need additional treatment.

Clinical Impact of Circulating Tumor Cells in Patients with Localized Prostate Cancer

“…However, the latter study did not perform a longitudinal follow-up of localized PCa patients for further prognostic evaluation [53]. Murray et al took a different approach by using density gradient isolation and detection of CTC by PSA immunocytochemistry on a large cohort of localized PCa patients [59]. Importantly, the authors reported a significant correlation between CTC detection and clinical variables such as PFS after a long follow-up period of 15 years.…”

Liquid Biopsy in Diagnosis and Prognosis of Non-Metastatic Prostate Cancer

“…Thus, in the study by Miyamoto et al [ 112 ], isolated from blood CTCs were investigated via whole transcriptome amplification, which allowed to predict dissemination of the CTCs to seminal vesicles and lymph nodes In a cohort of patients at 34 subjects. Another approach for label-free isolation of PCa CTCs, gel centrifugation, was proposed by Murray et al [ 113 ]. Notably, in this study, blood was collected from patients at 3 months post-radiotherapy.…”