Subclinical peripheral neuropathy is a common finding in colorectal cancer patients prior to chemotherapy

Abstract

Purpose: Of the numerous complications associated with cancer and cancer treatment, peripheral neuropathy is a deleterious and persistent patient complaint commonly attributed to chemotherapy. The present study investigated the occurrence of subclinical peripheral neuropathy in patients with colorectal cancer before the initiation of chemotherapy.

Experimental design: Fifty-two patients underwent extensive quantitative sensory testing (QST) before receiving chemotherapy. Changes in multiple functions of primary afferent fibers were assessed and compared with a group of healthy control subjects. Skin temperature, sensorimotor function, sharpness detection, and thermal detection were measured, as was touch detection, using both conventional (von Frey monofilaments) and novel (Bumps detection test) methodology.

Results: Patients had subclinical deficits, especially in sensorimotor function, detection of thermal stimuli, and touch detection that were present before the initiation of chemotherapy. The measured impairment in touch sensation was especially pronounced when using the Bumps detection test.

Conclusions: The patients with colorectal cancer in this study exhibited deficits in sensory function before undergoing chemotherapy treatment, implicating the disease itself as a contributing factor in chemotherapy-induced peripheral neuropathy. The widespread nature of the observed deficits further indicated that cancer is affecting multiple primary afferent subtypes. Specific to the finding of impaired touch sensation, results from this study highlight the use of newly used methodology, the Bumps detection test, as a sensitive and useful tool in the early detection of peripheral neuropathy.

Figure 1

The bar graphs show the mean (and standard error) skin temperature (°C) in the volunteer (black bars) and the colo-rectal cancer patient (gray bars) groups. The site measured is noted at the bottom of the graph. *= p<0.05.

Figure 2

The bar graphs show the mean (and standard error) for the QST measures of large myelinated fiber functions in the volunteer (black bar) and colo-rectal cancer patient (gray bars) groups. The results for the vonFrey touch detection threshold (g) for each test site are labeled at the bottom of the Figure 2A. The results for the bumps detection threshold (μm) performed using the index finger of the dominant hand are shown in Figure 2B. Finally, the slotted peg board times (s) for the dominant and non-dominant hands are shown in Figure 2C. ** = p <0.01.

Figure 3

The bar graphs show the mean (and standard error) for the sharpness detection thresholds (g) for the volunteer (black bars) and the colo-rectal cancer patient (gray bars) groups. The data for each site are indicated by the labels at the bottom of the figure.

Figure 4

The upward going bar graphs show the mean (and standard error) temperatures (°C) for the detection of Peltier probe warming from baseline at 32°C (first two pairs of upward going bars in each set of 4) and then the heat pain threshold (second pair of upward going sets of 4 bars) for the volunteer (black bars) and colo-rectal cancer patient (gray bars) groups. The downward going bar graphs show the mean (and standard error) temperatures (°C) for the detection of Peltier probe cooling from a baseline at 32°C (first two pairs of downward going bars in each set of 4) and then the cold pain threshold (second pair of upward going sets of 4 bars) for the volunteer (black bars) and colo-rectal cancer patient (gray bars) groups. The test sites are indicated at the bottom of the graph. *= p<0.05; **=p<0.01.

Figure 5

The line plot shows the cumulative observations of QST measures more than 2SD from the volunteer mean for each of the volunteers (black line) and the colo-rectal cancer patients (gray line). The bar graphs show the mean out-of-range QST observations per volunteer (black bar) and colo-rectal cancer patients (black bar). ***=p<0.001.