New Tool Suggests Dominance of Non-Painful Symptoms in Peripheral Neuropathy

Although other PROs have been developed to assess neuropathy, they fail to adequately capture the distinction between neuropathic pain and neuropathy, a problem that is also found in the pain literature, Dr. Mendoza added.

“Pain has been overemphasized as the hallmark of neuropathy and this is reflected in many pain questionnaires such as the Brief Pain Inventory, McGill Pain Questionnaire and Neuropathic Pain Scale, among others that were used in neuropathic studies,” Dr. Mendoza stated.

Numbness/Tingling Rated More Severe Than Pains

The TNAS questionnaire allows patients to rate the severity of their neuropathy-related symptoms in the last 24 hours, and takes less than 2 minutes to complete. It includes both sensory (10 items) and motor (3 items) aspects of CIPN, each rated on a severity scale of 0 to 10.

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The instrument was validated in 573 patients from 4 cohorts: 2 cohorts of MM patients receiving bortezomib targeted therapy, and 2 of patients with colorectal cancer (CRC) receiving oxaliplatin-based chemotherapy; both are known to induce peripheral neuropathy. Cross-sectional and longitudinal cohorts were included for each indication to enhance the psychometric evaluation of TNAS with respect to reliability/validity, as well as sensitivity to accumulating treatment dose.

Results showed that patients in both the MM and CRC cohorts rated the severity of their numbness or tingling to be significantly higher than the severity of their pain, as evaluated by the general pain item from the MD Anderson Symptom Inventory (MDASI; 4.6 ± 2.5 vs 3.6 ± 3.0 and 4.1 ± 2.7 vs 2.2 ± 2.9, respectively; P < .001 for both comparisons.

Other key symptoms reported in the MM and CRC cohorts included cramps in the hands/feet (2.38 ± 3.26 vs 1.36 ± 2.29,P < .05), sensations of pins/needles in the arms/legs (2.36 ± 2.86 vs 1.23 ± 2.34, P < .05), and trouble walking (2.35 ± 3.05 vs 1.17 ± 2.35, P < .05). Most TNAS items were more severe at follow-up, demonstrating the instrument’s sensitivity to accumulating dose.

The notion that nonpainful components of CIPN tend to be more prominent than pain is supported by previous research, Deidre Pachman, MD, pointed out in an interview with Clinical Pain Advisor, citing a study published in Supportive Care in Cancer in 2012. The findings showed that a majority of patients reported having “quite a bit” to “very much” numbness or tingling, while a smaller percent had this level of symptoms from shooting/burning pain.2