Standard Cancer Pain Scale Scores Often Fall Short

Modifying pain intensity scales to include frequency as well as intensity of pain may be a more accurate and efficient way of screening cancer patients for pain in the outpatient setting, according to findings from a recent study.

Researchers asked 452 cancer patients in an ambulatory clinic to assess their pain on a numeric scale according to intensity and frequency, and then compared those results to the way patients described their pain to providers during audio-recorded clinic visits. They found that patients, regardless of disease stage or type of cancer, were much more likely to discuss relevant pain during clinic visits than to report it on questionnaires, suggesting that commonly used screening tools may be insufficient to detect significant pain issues. The results are published in the Journal of Oncology Practice.

“This result raises interesting questions about the use of commonly accepted pain scales and our reliance on them to identify patients experiencing distressing pain,” the authors noted. “The Symptom Distress Scale and Pain Intensity Numeric Scale (PINS) may favor specificity over sensitivity, detecting patients who do not have pain better than identifying those who do. Clinically, this translates into potential missed opportunities to help patients who are experiencing relevant pain.”

PINS, which asks patients to rank the intensity of their pain on a scale of 1 to 10, is the most commonly used screening tool in the United States, the authors said. Although 4 is a common threshold or cutoff point indicating the need for follow-up, patients in the study who ranked their pain at 2 or 3 on questionnaires brought up relevant pain issues when talking with their providers. 

However, the accuracy of pain scale ratings improved after researchers modified the screening tool to include a question about pain frequency. For example, in addition to the standard question, “What is your pain level now?” a revised questionnaire might ask, “During the last week, how frequently has pain been a problem for you?”

“Using this combination of simple screening questions may be an extremely effective, efficient, and practical method of accurately identifying more patients with cancer whose quality of life is being negatively affected by distressing pain,” the authors wrote.

The study also highlighted the importance of assessing for pain early, as patients at all stages of disease discussed relevant pain in the clinic that was not reported on questionnaires.

“Certainly, patients with stage IV cancer are at high risk for pain, but our findings provide an important reminder that clinicians must remain attuned to relevant pain in patients with earlier stage disease, which may be a result of the effects of treatment or other etiologies,” the authors noted. “Future research should explore pain outcomes when lower PINS threshold scores and frequency screening questions are used in the ambulatory oncology setting.”