The management of cancer pain remains a significant clinical issue [1,2]. A systematic review and subsequent update by Deandrea et al. and Greco et al.  report that the rate of inadequate pain management has decreased from 46.6% to 31.8%. However, our assessment of patients referred to the Rapid Response Radiotherapy Program (RRRP) indicates that improvement in pain management may not be as reported [3–6].
Widely used in literature and in systematic reviews, the Pain Management Index (PMI) was a tool developed in 1994 to provide a standardized method of quantifying the adequacy of pain management . The PMI assigns an analgesic score for no pain medication, nonopioids (e.g., nonsteroidal anti-inflammatory drugs), weak opioids, and strong opioids as 0, 1, 2, and 3, respectively. Similarly, the patient's pain is scored with no pain being 0, mild pain being 1, moderate pain being 2, and severe pain being 3. The pain score is subtracted from the analgesic score, giving the PMI score as a measure of the adequacy of pain management. A negative value is interpreted as inadequate management and a value of greater or equal to 0 is considered adequate management.
Our first assessment of the adequacy of pain management in patients referred to the RRRP did not directly use the PMI tool. Instead, the study defined undertreatment as patients reporting moderate/severe pain and given weak opioids, nonopioids, or no pain medications . The study reported a decline in undermedicated patients from 1999–2001, and a subsequent increase from 2003–2006 . A retrospective analysis was later done for the same time period using the PMI tool. Because of the slight difference in the classification of inadequate pain management, the numbers cannot be compared directly. Nonetheless, an overall increase of undermedication was identified using a logistic regression analysis (P < 0.0001) . The most recent assessment of the adequacy of pain management at our center indicates a rate of undertreatment of 31% for 1999–2008 and 33% for 2009–2015 [5,6]. When comparing these two values, there is no change in the rate of inadequate pain management. Given these observations, the RRRP has not seen a decrease in patients that are inadequately medicated for their pain in the past few years.
Over the past 2 decades the PMI has become the predominant method of assessing the adequacy of pain management. However, it has its shortcomings including the inability to include analgesic dose, method, or schedule of drug administration, and the exclusion of other adjuvant medications such as steroids into its scoring system [5,6,8]. Another issue noted frequently in literature is that the PMI will assign patients with severe pain on strong opioids a score of zero [4,6,9]. This will include patients on strong opioids that have not been adequately titrated or have opioid-resistant pain. In these cases, the patients should be classified as undertreated. Because of this, it systematically reports lower rates of undertreatment . As stated by Greco, the PMI tool may be better suited for use as a process indicator given the ease in data collection and interpretation . The shortcomings of the PMI limit the conclusions that can be made on pain management when this tool is used . We suggest that there is an urgent need to focus on developing an assessment tool that will be able to accurately act as an outcome indicator to monitor the progress in cancer pain management. If we cannot accurately assess the adequacy of pain management, development of effective strategies for improving cancer pain management remains an elusive unmeasurable goal.
Financial support and funding
Conflicts of interest
There are no conflicts of interest.
1. Deandrea S, Montanari M, Moja L, Apolone G. Prevalence of undertreatment in cancer pain. A review of published literature. Ann Oncol 2008; 19:1985–1991.
2. Greco MT, Roberto A, Corli O, et al. Quality of cancer pain management: an update of a systematic review of undertreatment of patients with cancer. J Clin Oncol 2014; 32:4149–4154.
3. Kirou-Mauro AM, Hird A, Wong J, et al. Has pain management in cancer patients with bone metastases improved? a seven-year review at an outpatient palliative radiotherapy clinic. J Symptom Manage 2009; 37:77–84.
4. Mitera G, Zeiadin N, Kirou-Mauro A, et al. Retrospective assessment of cancer pain management in an outpatient palliative radiotherapy clinic using the pain management index. J Pain Symptom Manage 2010; 39:259.
5. Mitera G, Fairchild A, DeAngelis C, et al. A multicenter assessment of the adequacy of cancer pain treatment using the pain management index. J Palliat Med 2010; 13:589–593.
6. Vuong S, Pulenzas N, DeAngelis C, et al. Inadequate pain management in cancer patients attending an outpatient palliative radiotherapy clinic. Support Care Cancer 2015; 1–6.doi:10.1007/s00520-015-2858-7.
7. Cleeland CS, Gonin R, Hatfield AK, et al. Pain and its treatment in outpatients with metastatic cancer. N Engl J Med 1994; 330:592–596.
8. Mercadante S, Bruera E. Good… but bad news. J Clin Oncol 2015; 33:2119.
9. Yau V, Chow E, Davis L, et al. Pain management in cancer patients with bone metastases remains a challenge. J Pain Symptom Manage 2004; 27:1–3.
10. Greco MT, Roberto A, Coril O, et al. Reply to S. Mercadante et al. J Clin Oncol 2015; 33:2119–2120.