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Analysis of intraprostatic therapeutic effects in prostate cancer patients using [(11)C]-choline pet/ct after external-beam radiation therapy.

By:
Contributors: Melinda Wuest, PhD, Matthew Parliament, MD, FRCPC, Nawaid Usmani, MD, FRCPC
Curr Oncol. 2013 Apr;20(2):104-10. doi: 10.3747/co.20.1217.

Abstract

PURPOSE:

The objective of the present study was to analyze, with relatively high sensitivity and specificity, uptake properties of [(11)C]-choline in prostate cancer patients by means of positron-emission tomography (pet)/computed tomography (ct) imaging using objectively defined pet parameters to test for statistically significant changes before, during, and after external-beam radiation therapy (ebrt) and to identify the time points at which the changes occur.

METHODS:

The study enrolled 11 patients with intermediate-risk prostate cancer treated with ebrt, who were followed for up to 12 months after ebrt. The [(11)C]-choline pet scans were performed before treatment (baseline); at weeks 4 and 8 of ebrt; and at 1, 2, 3, 6, and 12 months after ebrt.

RESULTS:

Analysis of [(11)C]-choline uptake in prostate tissue before treatment resulted in a maximum standardized uptake value (suvmax) of 4.0 ± 0.4 (n = 11) at 40 minutes after injection. During week 8 of ebrt, the suvmax declined to 2.9 ± 0.1 (n = 10, p < 0.05). At 2 and 12 months after ebrt, suvmax values were 2.3 ± 0.3 (n = 10, p < 0.01) and 2.2 ± 0.2 (n = 11, p < 0.001) respectively, indicating that, after ebrt, maximum radiotracer uptake in the prostate was significantly reduced. Similar effects were observed when analyzing the tumour:muscle ratio (tmr). The tmr declined from 7.4 ± 0.6 (n = 11) before ebrt to 6.1 ± 0.4 (n = 11, nonsignificant) during week 8 of ebrt, to 5.6 ± 0.03 (n = 11, p < 0.05) at 2 months after ebrt, and to 4.4 ± 0.4 (n = 11, p < 0.001) at 12 months after ebrt.

CONCLUSIONS:

Our study demonstrated that intraprostatic [(11)C]-choline uptake in the 11 analyzed prostate cancer patients significantly declined during and after ebrt. The pet parameters SUVmax and tmr also declined significantly. These effects can be detected during radiation therapy and up to 1 year after therapy. The prognostic value of these early and statistically significant changes in intraprostatic [(11)C]-choline pet avidity during and after ebrt are not yet established. Future studies are indicated to correlate changes in [(11)C]-choline uptake parameters with long-term biochemical recurrence to further evaluate [(11)C]-choline pet changes as a possible, but currently unproven, biomarker of response.

 PubMed

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New platform for prostate cancer diagnosis to be presented at ISEV 2017

The Lewis Research Group will present exciting results about new blood tests for prostate cancer during 3 talks at the upcoming 2017 International Society of Extracellular Vesicles (ISEV) annual meeting in Toronto (May 18-21). ISEV is a global society of researchers studying exosomes and microvesicles, which are the exciting new focus of cancer therapy and diagnosis.

Dr. Desmond Pink will speak about “Microflow cytometry: The Apogee A50 is a sensitive standard tool for extracellular vesicle analyses in liquid biopsies”, Robert Paproski’s presentation is entitled “Using machine learning of extracellular vesicle flow cytometry to build predictive fingerprints for prostate cancer diagnosis”, and Dr. John Lewis will speak about “An extracellular vesicle blood fingerprint distinguishes between patients with indolent and aggressive prostate cancer at diagnosis”.

The team is looking forward to sharing these key advances that were made possible through the APCaRI prospective cohort.

- John Lewis