Abstract 275P
Background
In 2022, the U.S. Food and Drug Administration (FDA) approved Lutetium-177 Prostate-specific membrane antigen (Lu-177 PSMA). This approval was based on the VISION trial, in which Lu-177 PSMA demonstrated improved progression-free survival (PFS) and overall survival (OS) compared to standard therapy alone. PSMA is more strongly expressed in prostate cancer than in benign prostatic hyperplasia and correlates with Gleason Score and cancer grade. PSMA is involved in tumor growth by activating IP3K-AKT-mTOR signaling through folate metabolism. PSMA expression is suppressed by androgen receptor (AR) bound complexes with testosterone and promoted by unbound AR. In other words, inhibition of AR signaling enhances PSMA expression. These findings suggest that PSMA is involved in the mechanism of resistance to treatment in castration resistant prostate cancer (CRPC). Our previous study also showed that CRPC patients with PSMA expression in the blood circulating tumor cells (CTCs) have a shorter PFS. In this study, we aimed to determine the association between PSMA expression in CTCs and OS after the initiation of taxane-based chemotherapies in metastatic CRPC.
Methods
Forty-eight patients with metastatic CRPC treated with docetaxel followed by cabazitaxel were included in the study. PSMA expression in CTCs was analyzed over time, and the association between PSMA expression and OS was analyzed.
Results
Twenty-seven patients were positive for PSMA expression, and 21 patients were negative for PSMA expression in CTC. The analysis comparing patient backgrounds showed no significant differences with respect to Gleason Score, number of docetaxel treatments, prior ARATs administration, or metastatic site. On the other hand, patients with positive PSMA showed a longer time to acquire castration resistance. The log-rank test result showed shorter OS after initiation of docetaxel treatment in patients with positive PSMA than in those with negative PSMA (median survival at observation, PSMA-positive group: 618 days; PSMA-negative group: 1187 days; P=0.05).
Conclusions
The expression of PSMA in CTCs was associated with OS after initiation of taxane-based chemotherapy in metastatic CRPC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
26P - Subcutaneous trastuzumab versus intravenous trastuzumab for treatment of patients with HER2-positive breast cancer: A time, motion and cost-benefit assessment in a day care oncology unit in China
Presenter: Bei Sun
Session: Poster Display
Resources:
Abstract
27P - The biological characteristics of HER2-low in TNBC using mRNA profiling and molecular subtypes
Presenter: Asako Tsuruga
Session: Poster Display
Resources:
Abstract
28P - One-week ultra-hypofractionated partial breast RT in early breast cancer: 3DCRT vs IMRT
Presenter: Nurilla Zaynutdinov
Session: Poster Display
Resources:
Abstract
30P - Stereotactic body radiotherapy using cyberknife versus interstitial brachytherapy in accelerated partial breast irradiation on left-sided breast: A comparison of preliminary clinical result and dosimetric characteristics
Presenter: Ting-Na Wei
Session: Poster Display
Resources:
Abstract
31P - Prognostic implication of breast edema on preoperative breast MRI in breast cancer
Presenter: Ki-tae Hwang
Session: Poster Display
Resources:
Abstract
32P - Efficacy of olanzapine in the prophylaxis of delayed chemotherapy-induced nausea and vomiting in breast cancer patients receiving dose-dense AC with a steroid-sparing regimen: A single-center pilot study
Presenter: Manami Tada
Session: Poster Display
Resources:
Abstract
34P - Social support as the mediator of the association between unmet needs and happiness among women with early breast cancer
Presenter: Nithiya Sinarajoo
Session: Poster Display
Resources:
Abstract
35P - Prospective study assessing the efficacy and safety of a scalp cooling device for the prevention of alopecia in breast cancer patients undergoing (neo)adjuvant chemotherapy
Presenter: Winnie Yeo
Session: Poster Display
Resources:
Abstract
37P - To excise or not to excise: Preventive management of early breast cancer in atypical ductal hyperplasia patients
Presenter: Clarisse Hing
Session: Poster Display
Resources:
Abstract
38P - Exploring prognostic factors in patients achieving PCR after neoadjuvant therapy for triple-negative breast cancer: A retrospective study based on SEER data
Presenter: Lv Wenjie
Session: Poster Display
Resources:
Abstract