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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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The Bird Dogs: Pointing for the Prostate Cancer Cure

For years, Frank Sojonky hid his battle with prostate cancer from the world. But by 2004 he could hide it no longer, as the disease metastasized and began to spread. So when he learned from his oncologist, Dr. Peter Venner, that a chair in prostate cancer research was needed in Alberta, he made his personal goal to raise the funds to do it. That is how the Bird Dogs started and thanks to them and the Alberta Cancer Foundation, Dr. John Lewis and the Alberta Prostate Cancer Research Initiative are making important discoveries to improve the lives of those with prostate cancer.

Watch a video about the Bird Dogs.

- APCaRI