JRSM >
Volume 96, Number 8 >
Pp. 379-383
Department of Palliative Care and Policy, GKT School of Medicine, King's
College London
1 National Hospital for Neurology and Neurosurgery
2 Hammersmith Hospitals NHS Trust, London, UK
Correspondence to: Dr Jean Potter, Department of Palliative Care and Policy, GKT School of Medicine, King's College London, Weston Education Centre, Cutcombe Road, London SE5 9RJ, UK E-mail: jean.potter{at}kcl.ac.uk
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Of 130 patients approached, 125 took part. 25 (20%) of these had cancer related pain, mean score on an 11 point numerical rating scale 6.3 (median 6.0, range 3-10). Average age was 60 years (median 60, range 27-84); 56% were male. LANSS completion time was about five minutes, and the procedure was acceptable to all patients. The pain specialist diagnosed neuropathic pain in 14/25 patients, in 13 of whom the neuropathic pain was part of a mixed pain picture. The LANSS correctly identified 11 of these cases (sensitivity 79%; specificity 100%). The patient-completed section alone had a sensitivity of 86% and a specificity of 91%.
The LANSS is a simple and suitable screening test for neuropathic pain in patients with head and neck cancer related pain, although some modifications might improve it.
| INTRODUCTION |
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TOPSUMMARYINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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The Leeds Assessment of Neuropathic Symptoms and Signs Scale (LANSS) is a standardized bedside test to identify patients in whom neuropathic pain mechanisms predominate.5 This tool has two parts—a patient-completed section and a brief physical assessment. Five questions in the patient-completed section (maximum score 16) identify those who are experiencing phenomena associated with neuropathic pain: ‘pins and needles’ (paraesthesia); ‘red skin’ (autonomic changes); ‘sensitive skin’ (evoked dysaesthesia); ‘electric shock pain’; and ‘burning pain’ (spontaneous dysaesthesia). The physical assessment (maximum score 8) is designed to identify allodynia by stroking cotton wool over the painful and the anatomically equivalent non-painful area, and altered pinprick threshold (PPT) by use of a 23 gauge needle to assess perception of pinprick in the same areas. The LANSS identifies patients with neuropathic pain by combining the scores of a patient's verbal description of pain and the results of neurological examination. A cut-off score of 12 points or more (out of a total of 24), when compared with expert opinion, had a sensitivity of 83% and a specificity of 87%.5
Pain affects 40-90% of patients with malignant disease,6 and neuropathic pain occurs in about one-third of patients with cancer-related pain.7 It is usually a mixed nociceptive-neuropathic pain phenomenon.6,8 The LANSS tool was developed and validated by assessing patients with pure neuropathic pain of largely non-malignant origin. A simple and quick test to identify patients with neuropathic pain in the general oncology clinic would be an important first step in improved pain control. However, the diagnostic capabilities of the LANSS in cancer-related mixed-pathophysiology pain is unknown.
Although only around 5% of all cancers arise in the head and neck,9 their highly erosive nature, the rich innervation of the head and neck and the intensive treatment regimens instigated mean that they are a common cause of pain,7,10-11 and neuropathic pain in particular.7,12-13 Between 25% and 60% of patients with pain from head and neck cancer experience neuropathic pain.7,12-14
We therefore aimed to assess the acceptability and understanding of the LANSS by patients with head and neck cancer, and to calculate the sensitivity and specificity of the LANSS by comparison with medical expert opinion in these patients. In busy clinics a screening tool may be most useful when unaided patients can complete all parts; therefore the patient-completed subscores were also analysed separately to calculate a cut-off score with the highest sensitivity and specificity.
| METHODS |
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Patients were included in the study if they were over the age of 18, were able to understand and speak English, and had head and neck cancer. Those patients with head and neck cancer with small-volume disease (staged at T1N0M0) and those who received only minor treatment (local excision and/or brachytherapy) were excluded.
The study was approved by the local hospital research ethics committee. Written informed consent was obtained from all patients.
Measures and procedures
A single investigator, JP, collected all data. Demographic and medical data
(regarding disease severity, sequelae and treatments) were collected on all
surveyed patients from their medical notes, by use of standardized
proformas.
Initially all patients who agreed to take part completed the LANSS questions unaided. The investigator then reviewed the questions with each patient to verify patient understanding. If this review revealed questions that had initially been misunderstood by the patient, then the investigator clarified the answer with the patient and scores were amended accordingly. Where the question could not be answered by the patient either alone or in conjunction with the doctor, then the default answer was no (no score). Again this led in some cases to amended LANSS scores.
The investigator, using a standardized format, took a medical history and conducted a neurological examination including the sensory assessment component of the LANSS. Sensation (fine touch, pinprick and allodynia), power and appropriate tendon reflexes were assessed in all patients.
A pain specialist (JWS) who was blinded to the LANSS scores reviewed medical details of each case (demographic and medical data plus clinical assessment findings). The expert opinion of this pain specialist was used as the gold standard for identifying neuropathic pain in these patients.
Analysis
Acceptability to patients was expressed as a percentage:
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The sensitivity and specificity of the LANSS in these patients, compared
with expert opinion, were calculated by use of the cut-off score of 12
suggested in the original validation
study.5 The
individual components of the LANSS were assessed by 
2 tests to
identify which components were chosen more often by patients with neuropathic
pain than those with non-neuropathic pain. Fisher's exact test was used to
assess any association between two categorical variables when expected counts
calculated for 2 were below 5. The LANSS patient-completed
section alone was analysed to calculate a cut-off score with the highest
sensitivity and specificity.
Analysis was conducted with the Statistical Package for the Social Sciences version 10.1.
| RESULTS |
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TOPSUMMARYINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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Acceptability and understanding by patients
The LANSS was completed by all patients who were invited to do so.
Completion time was about five minutes, including the sensory assessment. The
full assessment could be conducted with the patient fully clothed in most
cases. 6 patients (24%) required help with the patient-completed section. Nine
answers were amended on review of these 6 patients. In total, 25 patients
answered five questions each. Amendment was necessary in 11 patients (9%)
(Table 2).
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Diagnosis of neuropathic pain
Expert opinion diagnosed neuropathic pain in 14/25 patients (56%). In 13/14
cases neuropathic pain was part of a mixed pain picture. Each pain quality
assessed by the LANSS was experienced more often by patients with neuropathic
pain than by those with non-neuropathic pain, but this reached statistical
significance only for items related to ‘sensitive skin’,
‘electric shock pain’, allodynia and altered PPT
(Table 3).
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With the suggested cut-off score of 12, the LANSS correctly identified 11/14 cases of neuropathic pain (sensitivity 79%; specificity 100%). Amendment of responses changed the total LANSS scores of 6 patients, but this had no effect on the sensitivity or specificity.
A cut-off score of 6 or more, with data from the unaided patient-completed section, gave sensitivity and specificity scores of 86% and 82%, respectively. When the amended patient-completed scores were used the sensitivity was unchanged but the specificity rose to 91%.
| DISCUSSION |
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TOPSUMMARYINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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Some of the LANSS questions were difficult for patients to complete accurately. For example, skin redness was associated with either pain or treatment. Patients with damaged mucous membranes experienced sensitive skin and burning sensations but these were not, on medical assessment, related to neuropathic pain mechanisms. Despite these drawbacks, a cut-off score of 6 (maximum 16) on the patient-completed subscore alone had a sensitivity and specificity of 86% and 82%, respectively. Amendment of patients' answers by giving no score to questions regarding sensitive skin and burning sensations in patients with damaged mucous membranes, and by asking whether skin colour change occurred only when pain was particularly severe, had no effect on the sensitivity but improved the specificity.
In this study, 1 in 5 patients attending a head and neck outpatient clinic had pain, and over half of these had neuropathic pain. Similar prevalence values have been found by others.2,7,12-14,16-19 The total LANSS score correctly identified 86% of these patients, and the patient-completed data offered the same sensitivity with only slight loss of specificity. Identification of patients with neuropathic pain is an important first step towards control of this difficult symptom. A shortened version of the LANSS, comprising a modified patient-completed section alone, could be used as a screening tool for neuropathic pain in the waiting area of busy oncology clinics.
| Acknowledgments |
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