Subclinical Peripheral Neuropathy Is Common in Treatment-Naive Multiple Myeloma Patients, Correlates With Decreased Fingertip Innervation Density
In a study reported in the Journal of Clinical Oncology, Kosturakis et al found that the majority of patients with multiple myeloma had subclinical peripheral neuropathy prior to chemotherapy and that deficits corresponded with decreased fingertip innervation density.
Study Details
In the study, quantitative sensory tests were used to assess the incidence of subclinical peripheral neuropathy in 27 treatment-naive multiple myeloma patients with no history of peripheral neuropathy and 30 age- and sex-matched healthy controls. Tests included assessment of skin temperature, sensorimotor function (grooved pegboard test), and detection thresholds for temperature, sharpness, and low-threshold mechanical stimuli (von Frey monofilament and bumps detection tests). Laser reflectance confocal microscopy was used to assess Meissner’s corpuscle density in the fingertips as a measure of innervation density.
Touch Detection and Sensorimotor Function
At least one subclinical deficit was present in 81.5% of multiple myeloma patients compared with 33.3% of controls. Touch detection thresholds (a measure of Aβ fiber function) were higher in patients at the palm (thenar eminence; P = .01) and volar forearm (P < .05) but not at the fingertip using von Frey monofilaments and at the fingertip using the bumps test (P < .01). Patients had significantly impaired sensorimotor function on the slotted pegboard test, as shown by significantly slower completion times with both the dominant hand (90.6 vs 69.4 seconds, P < .01) and the nondominant hand (86.3 vs 74.3 seconds, P < .01).
Heat and Cold
There were no differences between groups with regard to sharpness detection. Baseline skin temperature was higher for multiple myeloma patients at the palm (P < .05) but not the other two sites. Multiple myeloma patients had a significantly higher threshold for heat detection at all three sites (all P < .05), with heat pain threshold being similar in the two groups. Thresholds for cold detection were similar in the groups, but multiple myeloma patients had significantly elevated cold pain thresholds at the palm and volar forearm (both P < .05).
Reduced Innervation
Confocal microscopy showed that multiple myeloma patients had a significantly decreased mean density of Meissner’s corpuscles (2.63 vs 4.88/mm2, P < .01), with a significant correlation being observed between increasing bump detection threshold and decreasing Meissner's corpuscle density (ρ = −0.69, P < .001).
The investigators concluded: “Patients with [multiple myeloma] commonly present with sensory and sensorimotor deficits before undergoing treatment, and these deficits seem to result from disease-related decreases in peripheral innervation density.”
Patrick M. Dougherty, PhD, of The University of Texas MD Anderson Cancer Center, is the corresponding author for the Journal of Clinical Oncology article.
The study was supported by grants from the National Institutes of Health and National Cancer Institute. The authors indicated no conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
