AUSTIN, TXRegardless of the type of chemotherapy administered, patients with chronic chemotherapy-induced peripheral neuropathy (CIPN) all have “stocking and glove” symptoms of tingling, numbness, burning, and sharp pain that current treatment options do not abate, leading to investigations of both cellular mechanisms and newer therapeutic modalities, according to research reported upon during the American Pain Society’s 30th Annual Scientific Meeting.

Charles Loprinzi, MD, Regis Professor of Breast Cancer Research at the Mayo Clinic, Rochester, MN, noted that previously, an acute pain syndrome following paclitaxel infusion has been called “paclitaxel-induced arthralgia or myalgia.” His research suggests, however, that the paclitaxel acute pain syndrome represents sensitization of nociceptors as the putative mechanism.

The relationship between numbness, tingling, and shooting/burning pain in patients with CIPN, as measured by the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-CIPN20 Instrument, found that 41% of patients had “quite a bit” and “very much” numbness and tingling of the hands; however, only 13% reported the same parameters for shooting/burning pain and numbness.

The North Central Cancer Treatment Group has investigated four different treatments for CIPN: IV calcium/magnesium salts for patients receiving the FOLFOX regimen for colorectal cancer; gabapentin; baclofen/amitriptyline/ketamine; and scrambler therapy. Clinical trials with IV calcium/magnesium salts and gabapentin to date have failed to reduce CIPN;, the latter two treatments are showing promise, however.

A study of baclofen found that on the sensory subscale CIPN20, absolute score changes from baseline were statistically significant compared with placebo for tingling of the feet/hands (P=0.01) and shooting/burning of the feet and hands (P=0.04). Difficulty distinguishing between hot and cold also improved compared with baseline. Baclofen also resulted in increases in absolute score changes from baseline for cramps of the hands (P=0.05), and problems holding a pen (P=0.04); other small improvements were observed in difficulty walking, difficulty with stairs, and difficulty using pedals.

The “scrambler” therapy is a patient-specific cutaneous electro-stimulation device for CIPN approved by the FDA in 2009. The therapy is noninvasive and works by creating “non-pain” information in packets of rapidly varying impulses, which are then given noninvasively using the patient’s own nerves. The 30-minute long sessions use EKG pads; patients report a stinging, then a tingling, and can adjust the device to their own tolerance. Early experience and pilot data are positive, said Dr. Loprinzi.