Dose-dependent neurotoxic chemotherapy and corneal nerve morphological changes

Area of Science:

• Ophthalmology
• Neurology
• Oncology

Background:

• Chemotherapy-induced peripheral neuropathy (CIPN) is a significant dose-limiting factor in cancer therapy.
• CIPN causes nerve fiber damage and is challenging to detect early, often diagnosed after symptom onset.
• In-vivo corneal confocal microscopy offers a potential method for early CIPN detection.

Purpose of the Study:

• To investigate if corneal nerve parameters can enable early detection of CIPN.
• To assess dose-dependent effects of neurotoxic chemotherapy on corneal nerves.
• To longitudinally monitor corneal nerve changes during and after chemotherapy treatment.

Main Methods:

• Corneal nerve imaging using in-vivo laser scanning confocal microscopy in patients receiving taxane-based or oxaliplatin chemotherapy.
• Measurements of central cornea and inferior whorl nerve fiber parameters were taken at multiple time points: baseline, mid-treatment, end-treatment, and up to 12 months post-treatment.
• Comparison of corneal nerve parameters between patients with and without persistent CIPN.

Main Results:

• A dose-dependent reduction in corneal nerves was observed with increasing doses of neurotoxic chemotherapy, particularly with taxanes (p=0.02).
• Significant changes in average corneal nerve fiber length were detected earlier in the treatment course.
• Patients with persistent CIPN showed significantly lower corneal nerve fiber length compared to those without, especially in the taxane group (p=0.02 and p=0.006).

Conclusions:

• Average corneal nerve fiber length loss is a potential early clinical marker for monitoring CIPN progression.
• Imaging a broader area of the corneal nerve plexus, including the inferior whorl, may enhance the detection of early neuropathic changes.
• Corneal nerve analysis shows promise for early and objective assessment of chemotherapy-induced nerve damage.