Leslie A. Colvin

Incidence, prevalence, and predictors of chemotherapy-induced peripheral neuropathy: A systematic review and meta-analysis

ABSTRACT Chemotherapy‐induced peripheral neuropathy (CIPN) is a disabling pain condition resulting from chemotherapy for cancer. Severe acute CIPN may require chemotherapy dose reduction or cessation. There is no effective CIPN prevention strategy; treatment of established chronic CIPN is limited, and the prevalence of CIPN is not known. Here we used a systematic review to identify studies reporting the prevalence of CIPN. We searched Embase, Medline, CAB Abstracts, CINAHL, PubMed central, Cochrane Library, and Web of Knowledge for relevant references and used random‐effects meta‐regression to estimate overall prevalence. We assessed study quality using the CONSORT and STROBE guidelines, and we report findings according to Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidance. We provide a qualitative summary of factors reported to alter the risk of CIPN. We included 31 studies with data from 4179 patients in our analysis. CIPN prevalence was 68.1% (57.7–78.4) when measured in the first month after chemotherapy, 60.0% (36.4–81.6) at 3 months and 30.0% (6.4–53.5) at 6 months or more. Different chemotherapy drugs were associated with differences in CIPN prevalence, and there was some evidence of publication bias. Genetic risk factors were reported in 4 studies. Clinical risk factors, identified in 4 of 31 studies, included neuropathy at baseline, smoking, abnormal creatinine clearance, and specific sensory changes during chemotherapy. Although CIPN prevalence decreases with time, at 6 months 30% of patients continue to suffer from CIPN. Routine CIPN surveillance during post‐chemotherapy follow‐up is needed. A number of genetic and clinical risk factors were identified that require further study.

The effect of conduction block on the spinal release of immunoreactive-neuropeptide Y (ir-NPY) in the neuropathic rat.

&NA; Peripheral nerve injury may result in significant changes in neuropeptide production and the development of neuropathic pain behaviour. Rats with a chronic constriction injury of one sciatic nerve were used to study the spinal release of immunoreactive neuropeptide Y (ir‐NPY), using the antibody‐coated microprobe technique. Previous work has shown an increase in NPY synthesis by large to medium‐sized primary afferent neurones, as well as a new area of ir‐NPY release in the deep dorsal horn on the side of nerve injury, when compared to uninjured rats. The stimulus for spontaneous ir‐NPY release was unclear, but may have been due to ectopic neuronal discharges developing after nerve injury. This study used local anaesthetic to block all electrical input from the injured nerve. No change was found in the new zone of spontaneous release of ir‐NPY in the deep dorsal horn ipsilateral to nerve injury. It appears therefore, that ir‐NPY is released from the central termination of primary afferent neurones, without regulation from neuronal activity in the primary afferent neurones themselves.

IV. Managing chronic pain: a clinical challenge: new SIGN guidelines provide a practical evidence-based approach and identify research gaps

Chronic pain is common, with around 20% of the adult population suffering from moderate-to-severe chronic pain. 12 Chronic pain has been recognized as a long-term condition in its own right, rather than just a symptom, with evidence to support this from neuroimaging studies. 34 Like other longterm conditions, chronic pain has a significant impact on quality of life for sufferers and their families. It also has a much wider impact on society, with financial implications being very much greater than healthcare costs alone. 56 The majority of patients with chronic pain present are managed outside the specialist setting, mainly in primary care, although patients will make a variety of choices for self-management of their pain. 7 There is some evidence that current management is less than optimal, with around 60 –70% of patients being unhappy with their treatment. 1 Neuropathic pain can be especially difficult to diagnose, with resultant delay in starting appropriate therapy. 8 We need to develop approaches to managing chronic pain that are accessible and underpinned by current evidence and understanding of mechanisms, not just in specialist pain services, where a small minority of patients are seen, but also in the non-specialist and primary care settings. 91 0 Particularly for non-specialists, keeping up with the latest evidence in a variety of areas, and having the knowledge to critically assess new findings in specialist areas, such as chronic pain, can be difficult: hence the need for good quality, evidence -based clinical guidelines. There is also an urgent need to ensure that research priorities are directed towards the areas of clinical need where there is a lack of good quality evidence to underpin clinical practice.