The real #Movember for #ScienceSunday .

Most of you probably know that the pink ribbon in October means, breast cancer awareness month. I disagree with the commercialization of the pink ribbon and attempts to trademark it, but that’s another story. I want to talk about Movember. You’ve seen the mustaches and the hashtag. How many of you know it is for men’s health awareness? Specifically prostate and testicular cancer. I’m going to focus on prostate cancer.

PSA about PSA

Public service announcement about prostate-specific antigen screening: For many years, PSA testing was suggested to start at age 40. The current recommendation:

The American Cancer Society recommends that men discuss the possible risks and benefits of prostate cancer screening with their doctor before deciding whether to be screened. The discussion about screening should take place starting at age 50 for men who are at average risk of prostate cancer and expect to live at least 10 more years. It should take place at age 45 for men who are at higher risk, including African-American men and men who have a father or brother diagnosed with prostate cancer, and at age 40 for men at even higher risk.

For many years researchers in the trenches were finding that PSA screening often led to false positives. There’s too much variability in the PSA screening method.

Ex vivo MRI

The purpose of the study that I’m presenting was to take advantage of higher resolution MRI, using ex vivo samples in a pre-clinical high field MRI scanner (9.4T vs. 1.5T clinical MRI). Histology is orders of magnitude higher resolution even compared to the pre-clinical scanner. The idea was that better MRI images could be correlated with histology. Ultimately decisions are made based on histology, typically via biopsy. Identifying which features in MRI correlate with histology could set up a feed back loop to improve the in vivo MRI images. What’s shown below is an early proof of concept study.

I don’t know the PSA scores for the patients in the study below, but I’m sure they were high enough to justify biopsies. We were blinded to patient names and a lot of their health records for both privacy reasons and to remove bias. There are risks and side effects associated with getting a prostate biopsy. That’s part of the reason for changing the PSA screening recommendations. If you are curious what a human prostate looks like, there’s one pictured below. It’s about the size of the palm of your hand (at least my hand).

The other two figures show what the prostate looks like using MRI (panel A, C, and D) and histology (panel B). Panel A is a T2-weighted spin echo image. Panel C is a T2 map, i.e. a display of the actual T2 values. Panel D is an apparent diffusion coefficient (ADC) map. You can review the MRI terminology in the link below.

The first figure, which outlines the cancer with a dotted line in the histology image is from a 71-year-old patient. The second is from a 63-year-old patient without malignant cancer. In the examples below it isn’t obvious which MRI parameter best correlates with cancer. In the 71-year-old patient, the low T2 values along with low ADC values appears to correlate well with the tumor outlined in the histology slide. However, the 63-year-old patient also displays  low ADC values, whereas the T2 values are higher. Overall, with 9 patients, the T2 values were about 10 msec longer (P < 0.03) and the average ADC values were about 1.4 times larger (P < 0.002) when comparing normal peripheral zones vs. cancerous peripheral zones. With a larger sample size we hope to improve the correlation between both the in vivo and ex vivo MRI with histology.

References:

Medical Imaging 101 pt 3: MRI from my #CHMedicalImagingSeries

http://goo.gl/UVbiU

High-resolution MRI of excised human prostate specimens acquired with 9.4T in detection and identification of cancers: validation of a technique.

J Magn Reson Imaging. 2011 Oct;34(4):956-61. doi: 10.1002/jmri.22745.

Fan X, Haney CR, Agrawal G, Pelizzari CA, Antic T, Eggener SE, Sethi I, River JN, Zamora M, Karczmar GS, Oto A.

http://www.ncbi.nlm.nih.gov/pubmed/21928309

Doctors’ Associations Release New Recommendations for Prostate Cancer Screening

http://goo.gl/nieEIL

http://us.movember.com/faq