Editor's Commentary - A pilot study of endorectal magnetic resonance imaging and magnetic resonance spectroscopic imaging changes with dutasteride in patients with low risk prostate cancer

BERKELEY, CA (UroToday.com) - MRI and magnetic resonance spectroscopic imaging (MRSI) are non-invasive instruments to measure prostate size and metabolism.

MRI alone can detect prostate cancer (CaP) by a decrease in signal intensity on T2-weighted images. MRSI measures chemical compound in the tissue with high levels of citrate and low levels of choline in healthy prostate tissue and low citrate and high choline in malignant tissue. This pilot study sought to evaluate the effects of dutasteride on CaP in men with low-risk, untreated CaP using serial MRI and MRSI combined with serum and QOL assessments.

Ten patients with low risk CaP were studied. All had MRSI scans that demonstrated measurable spectroscopic malignancy in their prostate glands. They were on active surveillance or considering prostate shrinkage prior to brachytherapy. The measurable disease was defined as the presence of at least 3 contiguous voxels with a score of 4 or 5. Patients had either an IPSS of 8 or 0-7 with the intention of commencing on pre-brachytherapy prostate reduction. The dose of dutasteride used was 3.5mg, higher than the recommended BPH dose. Patients were assessed at 3-month intervals with serum PSA, DHT, and testosterone levels and they completed an IIEF-5 and QOL questionnaires. MR images were obtained at baseline and 1, 3, and 6 months after the start of dutasteride. On MRSI, the peripheral zone spectra were labeled as malignant if choline was higher than creatine based upon established criteria for labeling MR spectra for untreated patients.

They found that changes in MRSI-measured CaP volumes did not reach statistical significance. This may in part be due to the low volume of CaP in this patient cohort. Dutasteride use correlated with a decrease in citrate, thus appearing more similar to CaP. At 6 months the median value of MRSI voxels classified as malignant compared with baseline was 200%. When the number of MRSI voxels classified as malignant was compared with 1-month values, the 6-month median CaP volume did not change from the 1-month value. Three of nine patients had a decrease in CaP volume at 6-months vs. baseline. One patient discontinued dutasteride due to development of a rash at 3 months. At 6 months, the PSA decreased by 47%, DHT decreased by 92%and testosterone increased by 44%. Prostate volumes decreased by 25%. There were no significant improvements in QOL indices.

Chung HT, Noworolski SM, Kurhanewicz J, Weinberg V, Roach Iii M

 

BJU Int. 2011 Mar 24. Epub ahead of print.
10.1111/j.1464-410X.2010.10061.x

PubMed Abstract
PMID: 21435153

UroToday.com Prostate Cancer Section

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