Management of Cancer Pain

By  Dr. A.J. Hilmi

 

Introduction

     The number of cancer patients in the world is increasing. According to World Health Organization (WHO) estimates, 10 million new cancer patients are diagnosed every year globally. As the majority of cancer patients are diagnosed late with advanced disease, pain management and palliative care are the only realistic treatment options for them. Pain occurs in one third of patients receiving anticancer treatment. As a result, for them, pain relief and anticancer treatment should go in hand in hand. But unfortunately, around twenty-five percent of cancer patients die without adequate pain relief in spite of the fact that adequate pain control is available. An adequate control of pain in these patients can be achieved with rigorous and aggressive measures that are quite straightforward in clinical practice.

 

Causes of Cancer Pain

     Cancer pain can be grouped into several categories depending on the cause of pain. These are,

A.   pain related to cancer itself or tumor pressure

E.g. soft tissue, visceral, bone, metastasis

B.    treatment related pain

E.g. chemotherapy related mucositis, radiation induced pain

C.    debility related pain

E.g. constipation, muscle spasm

D.   pain due to concurrent disorder

E.g. spondylosis, osteoarthritis

 

Management of Cancer Pain

     Several guidelines are in use for the treatment of cancer pain, and all these guidelines acknowledge that analgesic therapy is the cornerstone of pain management. The goal of such therapy is to achieve optimal pain relief with minimum or tolerable side effects within an acceptable time frame.

     The WHO has described a three step analgesic ladder as framework for pain management. The method described in this ladder has been shown to provide adequate analgesia to ninety percent of cancer patients and seventy-five percent of the terminally ill cancer patients. It involves a step approach based on the severity of pain (if the intensity of pain is measured on a 0 to 10 numerical rating scale).

Mild pain (Pain score 1-4)

Step 1 analgesics. E.g. NSAIDs

Mild to moderate pain (Pain score 5-6)

Step 2 analgesics. E.g. weak opioids

Moderate to severe pain (Pain score 7-10)

Step 3 analgesics. Strong opioids E.g. morphine

 

     At each step an adjuvant drugs or a modality such as radiation therapy, chemotherapy or some surgical intervention may be considered for some selected patients. (Readers are referred to Pain Management: Current Concepts Part I and other chapters of this book for more information on WHO analgesic ladder.)

     Despite published guidelines for pain management in cancer patients, many patients experience considerable pain and half of them receive inadequate analgesia. 

    In Eastern Cooperative Oncology Group (ECOG) study, close to two-thirds of the physicians reported their own reluctance to prescribe opioids. The most frequent cause for the reluctance to prescribe opioids by the doctors is the fear of developing addiction, tolerance and side effects.

     Opioids, the major class of analgesics used in the management of moderate to severe pain, are an effective and easily titrated group of drugs, and have a favorable benefit-risk ratio. Most cancer patients require fixed dosing to manage the constant pain. The treatment of cancer pain leads to addiction in less than one-percent of patients who have no history of drug addiction. But the chronic cancer pain can be psychologically devastating because, it is a constant reminder to the patient of the incurable nature of the disease. Therefore, all available measures appropriate to the patient should be explored.

     It is vital that all health care professionals have a working understanding of the principles of the WHO analgesic ladder. The ladder advocates the use of one of the cheapest analgesics available, i.e. morphine. The control of cancer pain does not have to be limited to individuals. The lack of palliative care training and experience among the doctors can leads to underutilization of morphine.  When national legislations limit the availability of morphine, it is a part of the professional responsibilities of doctors to lobby the authorities to improve its availability.

 

References

Paice JA, Bell RF, Kalso EA, Soyannwo OA, editors. Cancer Pain: From Molecules to Suffering. Seattle: IASP Press; 2010.