Cancer Pain

What is it?

Cancer pain is pain caused by the cancer itself or by its treatment. It can start at diagnosis, during treatment or after treatment has finished, and it becomes more common as the illness advances. However, the severity of pain does not always reflect how far the disease has progressed.

Cancer pain often has more than one mechanism. Nociceptive pain, caused by tissue damage in bone, muscle or internal organs, and neuropathic pain, caused by nerve involvement, can occur together in the same person. Short, sudden flare-ups on top of constant background pain are known as breakthrough pain.

Pain is not just a physical symptom; it also affects sleep, appetite, mobility, mood and family life. Palliative care therefore approaches it as "total pain", taking in its physical, psychological, social and spiritual dimensions.

What causes it?

The main causes of cancer pain are:

• Direct effects of the tumour: pressure on, or spread into, bone, nerves, the spinal cord or internal organs.
• Bone metastases: cancer that has spread to bone can cause pain that worsens with movement, and collapse fractures in the spine.
• Treatment-related pain: persistent pain after surgery, nerve damage in the hands and feet caused by some chemotherapy drugs, tissue changes after radiotherapy, and mouth sores (mucositis).
• Associated problems: infection, constipation, immobility and muscle weakness.
• Causes unrelated to cancer: pre-existing back, neck or joint pain.

Anxiety, poor sleep and low mood do not cause pain directly, but they can make it feel worse and harder to cope with, so they are addressed as part of treatment.

How is it diagnosed?

Assessment begins with a detailed history: where the pain is, what it feels like, how severe it is, what makes it worse and how it has responded to medicines. Pain is usually scored from 0 to 10 and rechecked regularly, and the examination looks for its source and for signs of nerve involvement.

The type and stage of the cancer, current treatments, blood counts, and kidney and liver function all influence which medicines and procedures are appropriate. Existing scans are reviewed, and any new ones, such as MRI or a bone scan, are planned with the oncology team. Pain that is new or has changed in character is assessed separately, because it may signal a change in the illness or a treatment-related problem.

Treatment options

Treatment is multimodal and planned in close cooperation with the oncology team. It aims to reduce pain to a level the patient finds acceptable, protect mobility and sleep, and keep side effects to a minimum. The plan is reviewed regularly, guided by the priorities of the patient and their family.

Conservative care

• Medication: following the World Health Organization (WHO) approach, painkillers are chosen according to pain severity: paracetamol or anti-inflammatory painkillers for mild pain, and opioids such as morphine for moderate to severe pain, combined when needed. Wherever possible they are taken by mouth, at regular times rather than when pain returns, and at doses adjusted to the individual. Separate "rescue" doses are planned for breakthrough pain.
• Adjuvant medicines: for nerve pain, certain antidepressants and anti-seizure medicines, and in some situations corticosteroids, may be added (neuropathic pain).
• Preventing side effects: anyone taking opioids starts preventive treatment for constipation, and nausea and drowsiness are monitored closely.
• Cancer-directed treatment: for pain from bone metastases, radiotherapy and medicines that reduce bone breakdown can help ease pain.
• Physiotherapy and psychological support: safe movement programmes, relaxation techniques and psychological support make pain easier to cope with.

Interventional pain treatments

For selected patients whose pain is not controlled by medicines, or who cannot tolerate their side effects, procedures aimed at the source of the pain may be considered:

• Sympathetic nerve blocks: a coeliac plexus block for cancers of the pancreas and other upper abdominal organs, or a superior hypogastric plexus block for pelvic cancers, can reduce pain signals from internal organs (abdominal and pelvic pain).
• Epidural catheter: a thin catheter placed in the epidural space of the spine delivers pain medicines close to the spinal cord and nerve roots.
• Intrathecal port: pain medicines are delivered through a port under the skin and a connected catheter into the fluid around the spinal cord. This allows much smaller doses than by mouth and can reduce side effects elsewhere in the body.
• Vertebroplasty: for painful collapse fractures of the spine caused by metastases or multiple myeloma, bone cement is injected into the vertebra under imaging guidance.

Whether these methods are suitable depends on the type of pain, the patient's general health, blood clotting results, infection risk and the cancer treatment plan. In suitable patients they can provide a meaningful reduction in pain and in the need for medicines, but results vary from person to person and each procedure has its own risks.

When does palliative care come in?

Palliative care is not just for the last stage of life. It aims to protect the quality of life of patients and their families, and it can be provided alongside cancer treatment from the early stages. Pain management is a core part of this care, and the patient's comfort, dignity and own wishes stay at the centre of the plan at every stage.

When should you see a doctor?

If your pain is not well controlled, is disturbing your sleep or daily activities, or if side effects are troubling you, talk to your oncologist and consider an assessment by an algology (pain medicine) specialist. Pain treatment can accompany cancer care at every stage; you can request an appointment through our contact page.