Cancer Pain

TOPICS:
1. How does Cancer cause Pain?
2. What types of Cancer Pain are there?
2. How is Cancer Pain Treated?
3. What are the side effects of opioids medications?
4. What happens if opioids are insufficient for reducing my pain?

How does Cancer cause Pain?
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​Cancer itself does not contain nerves and therefore, by itself does not cause pain directly. However, it can cause pain by:

• Direct Pressure: As a tumour grows, it can press on nearby organs, bones, or nerves. This pressure can irritate the tissues and cause pain. For example, a tumour in the lung can press on the pleura, the lining of the lung, which can cause sharp chest pain.
• Inflammation: Tumors can also cause inflammation in the surrounding tissues. Inflammation is the body's natural response to injury or infection, and it can cause pain, swelling, and redness.
• Bone Damage: Some cancers, such as bone cancer or cancers that have spread to the bones, can damage the bones themselves. This can cause pain, weakness, and fractures.
• Spinal Cord Compression: In some cases, tumors can press on the spinal cord. This is a serious condition that can cause pain, numbness, and weakness in the arms and legs.
  
  

Pain caused by cancer can be constant or intermittent, and it can range from mild to severe. It's important to talk to your doctor about any pain you're experiencing, so they can determine the cause and recommend treatment options.

What types of Cancer Pain are there?

Acute cancer pain refers pain that is brief. This may be due to an underlying complication of cancer (eg tumour bleeding, cancer-related bone fractures) or it may be arising from a treatment (eg. surgery or acutely following radiotherapy)

Chronic cancer pain refers to pain that lasts longer than 6-12 weeks. This pain is often a result of a tumour growing or spreading, causing inflammation, direct pressure, bone damage or spinal compression. 

Breakthrough cancer pain are flares of pain that occur on the background of chronic cancer pain. It may be triggered by the cancer, treatment and activities. Very frequently, there can be no apparent cause. 

How is Cancer Pain Treated?
The treatment of cancer pain is individualized and this is based on the severity of the pain, life-expectancy, response to treatment and underlying medical and psychological issues. As such, there is no one-size-fits-all strategy.

Cancer Pain is frequently treated with medications. These may include simple over the counter medications such as Paracetamol and Ibuprofen. However, if your pain does not respond to this, your doctor may discuss starting prescription medications for the treatment of your pain.

When the pain is severe, opioids may be required to help alleviate your pain. Opioids are narcotic medications (eg. morphine, oxycodone, tramadol and fentanyl). These medications are very effective and can help provide relief for more than 80% of patients with cancer pain.

A small proportion of patients will find their pain difficult to treat despite Opioids. Depending on the circumstances, advanced interventional pain techniques may be utilized by your Pain Specialist. Sometimes, psychological interventions can also be useful.

What are the side effects of opioids medications?
Opioids, while effective in managing pain, can also bring about a range of side effects, which can vary depending on factors such as the specific opioid used, dosage, individual sensitivity, and duration of use. Some common side effects of opioids include:

1. Constipation
2. Nausea / Vomiting
3. Drowsiness / Sedation
4. Confusion / Cognitive impairment
5. Respiratory depression
6. itching
7. Physical Dependence / Withdrawal
8. Tolerance
9. Hormonal effects
10. Increased risk of falls and fractures

However, it is important to understand that these medications, when used under a supervision of a Pain Specialist is oftentimes safe. If you are experiencing some of these side effects, it is important to report this to your prescriber. 

What happens if Opioids are inadequate?
Generally, opioids are considered inadequate if they cause:

• Excessive side effects
• Inadequate pain relief despite dose escalation

In such cases, your Pain Specialist will attempt to find out the reasons for treatment failure. The subsequent management will depend on the reason for treatment failure and the strategies include:

• Intravenous Medications
• Subcutaneous Medication
• Pain Procedures
• Surgery 
• Radiation Therapy
• Chemotherapy

Examples of Pain Procedures include:

• Destruction of nerves that supply the painful organ (eg. Celic Plexus Neurolysis)
• Infusion of medications around nerves (eg. Intrathecal pump)

Dr Christopher Liu is a Pain Specialist who treats a variety of pain conditions including Cancer Pain. He provides holistic care for patients with cancer pain. In addition, he also performs image-guided interventional procedures for selected patients with cancer pain in the operating room.
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In advanced pancreatic cancer, pain may arise from irritation of the abdominal wall by tumour deposits (metastases) or invasion of nerves that lie behind the head of the pancreas 

Most cancer pain can be treated successfully with medications. However, a small number will require more advanced pain management strategies. The photo above demonstrates needles placed next to the nerves that supply the pancreas. Destructive of these nerves can help with reducing pain from pancreatic cancer.