In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 35, No. 15_suppl ( 2017-05-20), p. 5049-5049
Abstract:
5049 Background: A heterogeneous landscape of patients with metastatic castration-resistant prostate cancer (mCRPC) exists in current clinical practice. We investigated the prognostic value of CTC enumeration and dynamics, in the context of second-line endocrine therapies (i.e. abiraterone or enzalutamide). Methods: In a prospective, multicentre study blood samples were collected from patients with mCRPC at baseline (n = 147) and follow-up (n = 95/147(64.6%)). At baseline, patients were stratified in favourable ( 〈 5 CTCs/7.5mL) and unfavourable (≥5 CTCs/7.5mL) groups, whereas at follow-up, in those demonstrating a stable, in- or decreasing CTC count. PFS and OS were compared between groups. PSA changes at 10-12 weeks were evaluable in 83 patients. Results: Patients with ≥5 CTCs/7.5 mL (n = 59) at baseline had a shorter PFS (3.9 vs. 11.3 months, p 〈 0.0001) and OS (9.34 months vs. not reached, p 〈 0.0001). Patients demonstrating increasing CTCs (n = 21) on therapy had a shorter PFS (4.03 vs. 10.36 vs. 13.08 months, p 〈 0.0001) and OS (11.2 months vs. not reached, p 〈 0.0001), compared to patients with decreasing (n = 41) and stable (n = 33) CTCs, respectively. Multivariate Cox regression showed that the number of CTCs (HR (95%CI): 1.0054 (1.0006–1.010), p= 0.0260) and an increasing follow-up CTC count (HR (95%CI): 2.8987 (1.2856–6.536), p= 0.0103) were independent predictors of PFS. CTC increase was the sole independent predictor for OS (HR (95%CI): 7.3512 (1.7953–30.101), p= 0.0055). At 10-12 weeks, a PSA response of ≥30% and ≥50% was achieved in 46/83 (55.4%) and 33/83 (39.8%) patients, respectively, which was statistically different between chemo-naive or -pretreated patients (≥30%: p= 0.0395), patients with increasing, stable or decreasing CTC counts (≥30%: p= 0.0019; ≥50%: p= 0.0032), and patients with increasing or stable/decreasing CTC counts (≥30%: p= 0.0006; ≥50%: p= 0.0014). Conclusions: CTC levels are associated with PFS and OS in mCRPC patients, starting a new line of endocrine therapy. Follow-up CTC enumeration is associated with PSA response and its dynamics is an independent predictor of PFS and OS, thereby demonstrating the pharmacodynamic properties of CTCs.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2017.35.15_suppl.5049
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2017
detail.hit.zdb_id:
2005181-5
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