Brain activity associated with chronic cancer pain.
BACKGROUND
The number of neuroimaging studies that examine chronic pain are relatively small, and it is clear that different chronic pain conditions activate diverse regions of the brain.


OBJECTIVE
Cancer patients presenting for diagnostic positron emission tomography (PET) imaging were asked to rate their spontaneous baseline pain score. Twenty patients with either no pain (NRS = 0) or with moderate to severe pain (NRS = 4) were invited to participate in this study to determine the difference in brain activity in cancer patients with moderate to severe chronic pain versus no pain.


METHODS
Prospective, non-randomized, observational report.


METHODS
Academic medical center.


METHODS
Patients had a 2-D PET scan with the radionuclide 18F-fluoro-2-deoxyglucose (FDG) at a dose of approximately 20 mCi. Each individual raw PET scan was coregistered and normalized to standard stereotactic space. Differences in regional glucose metabolism were then statistically compared between patients with moderate-to-severe pain and patients with no pain.


RESULTS
The NRS pain score in the patients with moderate to severe pain (n = 11) was 4.5 [4.0-6.0] (median [interquartile range]) versus 0.0 [0.0-0.0] (p < 0.001) in the group with no pain (n = 9). Compared to patients with no pain, patients with moderate to severe pain had increased glucose metabolism bilaterally in the prefrontal cortex, BA 9-11. Unilateral activation was found in the right parietal precuneus cortex, BA 7. There were no areas of the brain in which there was decreased activity due to moderate to severe pain.


CONCLUSIONS
Our results showing a preferential activation of the prefrontal cortex are consistent with results from studies showing that affective pain perception and negative emotions play an important part in the chronic pain experience.


CONCLUSIONS
This was not a randomized clinical trial. Patient medication was not controlled.
Buvanendran
Asokumar
A
Department of Anesthesiology, Rush University Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA. Asokumar@aol.com
Ali
Amjad
A
Stoub
Travis R
TR
Kroin
Jeffrey S
JS
Tuman
Kenneth J
KJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D002908:Chronic Disease; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications*; D010146:Pain / Q000000981:diagnostic imaging* / Q000209:etiology; D049268:Positron-Emission Tomography; D011868:Radioisotopes; D055815:Young Adult
D011868:Radioisotopes; D019788:Fluorodeoxyglucose F18