A Pilot Study To Define Chemical Coping in Cancer Patients Using the Delphi Method

Introduction

Pain is a devastating symptom in advanced cancer, and opioids have become a mainstay of pain management. ¹ However, physicians are often reluctant to prescribe opioids because of the risk of side effects and addiction.

The term “coping chemically” was first coined in 1995 with the frequency of alcoholism among cancer patients. ² A specific definition was not provided at the time, but the authors discussed that alcoholic patients were educated on “the difference between physical pain, suffering, and coping chemically.” Since then, clinicians and researchers alike have applied the term “chemical coping” heterogeneously. Specifically, some have used the terms chemical copers, aberrant behavior, and substance abusers interchangeably, while others have considered chemical coping as a distinct entity along the spectrum of opioid misuse in the chronic pain and cancer pain settings.^3–5 More recently, Del Fabbro defined chemical coping as the use of variable amounts of “opioid analgesics to cope with their psychological or spiritual distress.” ⁶

Although “chemical coping” is used by clinicians and investigators, the lack of definitional clarity poses a barrier to effective clinical care, education, and research.^7,8 A better understanding of the key features of chemical coping and definition can help us to communicate effectively among clinicians, make the proper diagnosis, and facilitate proper patient care. In this study we conducted a Delphi survey among palliative care and pain specialists internationally to identify a consensus definition for chemical coping with opioids. We also assessed warning signs for chemical coping.

Methods

An expert panel was organized consisting of 19 cancer pain specialists in Europe, the United States, South America, and Asia. This is a convenience sample selected based on the following criteria: a researcher who had published articles regarding cancer pain, opioids, addiction, and dependency or a physician who had been practicing palliative care full-time for more than three years after training and currently active in clinical practice. The survey was distributed through an e-mail with a link to an online survey system (SurveyMonkey^®).

The Delphi survey approach consisted of two rounds of questions. The first round consisted of questions related to participants' characteristics, concepts regarding the definition of chemical coping, and related warning signs. Concepts and factors reflected in the questions and response choices were drawn from previous studies.^9–11 The second round consisted of questions confirming the definition of chemical coping elicited from the results of the first survey (responses that had garnered agreement among at least 70% of the participants) and also re-asked questions that had an agreement level between 50% and 70% in the first round.

A five-point Likert scale ranging from “strongly disagree” to “strongly agree” was used to assess agreement with each proposed definition component, aberrant behavior, or warning sign. The participants were also given the opportunity to provide suggestions or comments in an open-ended question, especially in case of disagreement. These comments were taken into account to formulate the next round. The results from all respondents were collated and analyzed toward the development of consensus. Consensus in this study was defined a priori as agreement (i.e., “agree” or “strongly agree”) by a minimum of 70% of the experts. Survey results were analyzed with descriptive statistics.

Results

Discussion

The Delphi process of this study (see online Supplementary survey at www.liebertpub.com/jpm) reached the following consensus definition: “Chemical coping with opioids is the use of opioids to cope with emotional distress and is characterized by inappropriate and/or excessive opioid use.” The warning signs selected by the expert group were related to psychiatric history, substance abuse, alcoholism, and smoking history.

Chemical coping is a commonly used but ill-defined term. Several groups have tried to describe it in the context of malignant chronic pain and cancer pain.^2,12,13 The definition of chemical coping here is based on the consensus of a panel of international experts. Further research is needed to operationalize this definition and to assess its inter-rater reliability before this term can be adopted in clinical practice.

How is chemical coping related to addiction? Chemical coping is a wider concept than addiction. The American Society of Addiction Medicine defined addiction as “a primary, chronic disease of brain reward, motivation, memory and related circuitry…. This is reflected in an individual pathologically pursuing reward and/or relief by substance use and other behaviors.” Within our definition of chemical coping, it is important to recognize the spectrum of severity. In the mildest form, chemical coping denotes the occasional overuse of opioids to cope with emotional distress or suffering, without the craving, behavioral issues, and functional impairment that characterize addiction. In the most severe form, maladaptive chemical coping is essentially a component of addiction, because the lack of opioids results in severe emotional distress/dysphoria that in turn drives the excessive and inappropriate use of opioids and dysfunctional behaviors. Thus, for patients with warning signs or suspected of chemical coping, the health care team should be proactive in addressing the patients' emotional needs, providing proper education on safe opioid use, and monitoring them for aberrant behaviors.

Until now, most of the studies concerned with warning signs of chemical coping have been performed in patients with chronic noncancer pain. For cancer pain, our respondents agreed that important warning signs for chemical coping were depression (highest level of agreement), followed by psychiatric disease, history of substance abuse, positive CAGE screening, history of alcoholism, and history of smoking. We previously reported that undocumented alcoholism was frequent in patients with advanced cancer, and that it was associated with prolonged use of opioids in head and neck cancer patients after completion of chemoradiation, as well as increased pain expression and higher opioid doses.^14–19 In line with the first report of chemical coping, ² most respondents in our study agreed that alcoholism is a warning sign for chemical coping. Although there have been no reports suggesting a relationship between chemical coping and a history of smoking, respondents also suggested smoking as a warning sign for chemical coping. Psychiatric disease, which was identified as a warning sign for chemical coping in our study, also has been consistently reported as a warning sign for opioid-related problems in noncancer and cancer patients.^{14,16,20–23} Warning signs identified in our study may support further research to screen for chemical coping and develop appropriate interventions.

Our study had a relatively high response rate (first round: 14/19, 74%; second round: 12/19, 63%) and a short time interval between the first invitation and completion of the second round. However, inherent in the Delphi study design itself, this study has some limitations. ²⁴ The number of participants was small and was based on a convenient sample, which could introduce bias. ²⁴

To our knowledge, this is the first attempt to reach a consensus on definition of and warning signs for chemical coping among experts in pain management and palliative care. Once operationalized, this consensus definition may help clinicians and researchers alike to identify individuals who are misusing opioids, to communicate with each other clearly, and to devise proper management strategies for optimizing symptom control while minimizing harms associated with opioid misuse.