Why Is Management of Cancer Pain Still a Problem?
Authors: Martin R. Stockler, Nicholas R.C. Wilcken
Journal: Journal of Clinical Oncology (2012)

What is the probability that your next patient will have pain that warrants analgesia, and that you will manage it adequately? Much of our knowledge about the prevalence, burden, and heterogeneous management of cancer pain is based on the seminal study that was reported in 1994 by Cleeland et al from the Eastern Cooperative Oncology Group (ECOG). Their report showed that two thirds of medical oncology outpatients with advanced cancer required or used analgesics, and that analgesic prescribing was inadequate for approximately 40% of these patients. Numerous evidence-based guidelines and initiatives to improve oncologists’ management of cancer pain were released after this report. Is it reasonable to expect that pain management in cancer care has therefore improved? Maybe it should not surprise us that Fisch et al have again found, 18 years later, that two thirds of surveyed medical oncology outpatients required or used analgesics. However, it should definitely surprise and disappoint us that analgesic prescribing was still inadequate in 33% of these patients. The results were almost identical when the same patients were assessed 1 month later. The odds of inadequate analgesic prescribing were doubled in patients from minority groups. Typical reactions to this implied collective criticism might be to look for faults in the research that would make the results look worse than they should, or to assume that the results are applicable to others’ practices, but not to our own. Appraisal of this study’s methods provides no comfort or reassurance: if anything, its inherent biases strengthen the findings and conclusions. The study was limited to patients with one of the four most common cancers, but the findings are unlikely to be better in other malignancies. Clinicians interested enough to participate in this study were unlikely to have performed worse than their peers, especially knowing that their analgesic prescribing was being assessed. Patients rated their pain “at its worst over the last 24 hours” on a scale from 0 (none) to 10 (as bad as you can imagine). Analgesic prescribing was deemed adequate for mild pain (score of 1 to 4) if any analgesic was prescribed, adequate for moderate pain (score of 5 or 6 of 10) if any opioid was prescribed, and adequate for severe pain (score of 7 to 10) if a strong opioid was prescribed. This classification is conservative and ignores deficiencies that might result from insufficient doses and/or frequency of dosing. The findings of Fisch et al, 2 like those of Cleeland et al 18 years earlier, are likely to represent a best-case scenario for medical oncologists’ recognition and management of pain. A recent survey and accompanying editorial reinforce the observation that efforts to improve the management of cancer-related pain have had little effect on medical oncologists’ attitudes and practice. The barriers to pain management that were rated as most significant in these recent articles were almost exactly the same 20 years ago: poor assessment, patients’ reluctance to take opioids, and patients’ reluctance to report pain. In addition, only one in six responding medical oncologists reported frequent referrals to specialists in either pain or palliative care. Most discouraging was that scarcely one third of those who were approached completed the survey. Clearly more work is needed, perhaps in medical school, but certainly in residency and fellowship programs. More encouraging is that since the year 2000, Journal of Clinical Oncology has published more than 20 randomized trials, systematic reviews, or evidencebased guidelines of interventions aimed at improving pain associated with cancer and its treatment. Bone pain is common after treatment with granulocyte colonystimulating factors (GCSFs). Kirshner et al previously reported that two thirds of patients receiving chemotherapy that was supported by GCSFs reported some pain, and one quarter rated the pain with a score of 5 or more of 10. The randomized, placebo-controlled trial by Kirshner et al that was reported in the article that accompanies this editorial shows that naproxen 500 mg twice daily for 5 to 8 days reduced the proportion of patients who reported any pain by 10% (71% v 61%; P .02), and severe pain by 8% (27% v 19%; P .05), probably a real effect, albeit a modest one. The main strengths of this trial are its randomized, placebocontrolled design, daily assessment of pain, and appropriate statistical analysis. Its main limitation is the absence of information about the possible adverse effects of naproxen used prophylactically over multiple cycles of chemotherapy. Patients were observed for only one cycle, and the evaluation of safety was based only on reported serious adverse events (a total of 12 in 510 patients). The adverse effects of naproxen and similar nonsteroidal anti-inflammatory drugs are well known and include the consequences of gastro-esophageal toxicity (nausea, dyspepsia, reflux, abdominal pain, and upper GI bleeding) and renal toxicity (renal impairment and fluid retention, especially when used with antihypertensive drugs that affect angiotensin signaling). Many of these problems can occur during chemotherapy without naproxen. The absence of randomized data about the frequency and severity of these problems in patients undergoing chemotherapy with and JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 30 NUMBER 16 JUNE 1 2012