Types of cancer pain

Pain is a defence mechanism that the body uses to signal the presence of a threat. It is a language that your nervous system uses to alert you to a problem and motivate you to take action to avoid further damage to your body. For example, if you put your hand on something hot a message provokes your immediate reaction to move your hand away.

Cancer pain is common in the early stages of the disease, occurring in 30-50% of cancer patients at this stage. Pain symptoms are a factor in 64% of all cancer diagnoses and often allow people to receive timely treatment. In advanced stages of cancer, pain affects between 70-90% of patients with advanced, metastatic or terminal disease.

Everyone experiences pain differently and the way it presents and evolves during the course of the disease is unique, manifesting itself with different frequency and intensity.
An important distinction is between chronic pain (that is continuously present) and acute pain (that arises suddenly with very high intensity).

This app was devised to track episodes of acute pain, commonly referred to by doctors as breakthrough cancer pain (abbreviated as BTcP). BTcP was first defined in a 1990 scientific article as “a transient increase in pain of more than moderate intensity (ie, an intensity of “acute” or “stabbing”), which overlaps with a moderate or less than moderate baseline pain intensity”.

BTcP is a rapid onset, temporary (average duration is 30 minutes), severe flare-up of an underlying pain for which therapy is already being taken. BTcP can be controlled with additional therapy but to identify the appropriate intervention your doctor needs to have detailed information about your BTcP episodes.

Why does cancer cause pain?

The first thing to understand is that the intensity of cancer pain is not necessarily related to the severity or progression of the disease – a small tumour in a particular location can compress a nerve, giving rise to greater pain than a larger and more severe tumour in a different position.
Physical and pharmacological interventions to cure cancer can also cause pain and many cancer survivors have pain that continues after the cancer is eradicated and treatment ends.

Pain in general – not just cancer pain – is divided into three categories: nociceptive, neuropathic, mixed pain.

Nociceptive pain: in scientific language, pain receptors are called “nociceptors”. Nociceptive pains originate from irritation of these nociceptors that are capable of picking up various stimuli, such as touch, cold or heat and also pain. Pain receptors are found in our skin, bones, joints, muscles and internal organs (except the brain and lungs).
Nociceptive pain is of two kinds: “somatic” and “visceral”.
– Somatic pain typically manifests as pulling, stinging or drilling sensations in a specific point and is caused by irritation of skin, muscular, joint or bone receptors.
– Visceral pain is caused by receptors in the organs of the chest or abdomen. They are crampy and vague, making them more difficult to locate and can radiate to other parts of the body.

Neuropathic pain: originates directly in the nerve, not from a pain receptor. The cause of the pain is due to a neuropathy (inflammation or injury of a nerve). In this case, the pain can manifest itself as a sensation of heat, burning or stabbing pain attacks, often they are not perceived at the point from which they originate but in the sector of the body innervated by that nerve. For example, pain in a lower limb caused by a herniated disc compressing a sciatic nerve root at the lumbar level.

Mixed pain: both neuropathic and nociceptive pains are contemporarily present. The treatment of this kind of pain is especially challenging as it is often difficult to understand that both types of pain are present.

Consequently, cancer pain can be nociceptive, where a tumour mass causes compression or irritation of nearby tissues or organs (bone metastases, infiltration of tissues and muscles, ulceration of skin or mucous membranes), or neuropathic, where cancer treatment causes nerve damage or the tumour itself releases chemical substances(cytokines) that induce or increase neuropathic pain. These can also cause resistance to analgesic drugs and abnormally acute perception of pain, a phenomenon known as hyperalgesia. Cancer pain can also be mixed, with both nociceptive and neuropathic causes.

Finally, as already mentioned, in some cases it is the cure (for example, surgery, radiotherapy or chemotherapy), not the cancer itself, that can cause pain.

Why you should track pain episodes

Despite the availability of effective treatments, in many cases, cancer pain is not adequately treated and controlled. But cancer pain should not be endured because lack of effective pain control can adversely affect treatment outcomes and quality of life. Furthermore, the persistence of a pain stimulus can provoke alterations in the nervous impulse, tending to strengthen it and making it less treatable.

There is also a psychological dimension to physical pain (fear, helplessness) that makes it worse and extends the consequences of acute pain beyond the minutes of each episode.
AIOM (the Italian Association of Medical Oncology) highlights the role of pain in the life of the cancer patient by introducing the concept of “total pain”. Total pain is understood as the suffering not only of the patient but also of their family in the course of the disease.

Each person and their disease are unique. Doctors are well aware that everyone experiences pain differently and that there is no common tolerance threshold. Learning to understand your pain and establishing effective ongoing communication with your doctors can contribute greatly to their ability to intervene alleviating both physical and psychological suffering.

For these reasons, it is important to ask for pain relief and actively engage in pain identification and management. The first necessary step is to know your pain and provide your doctors with all the information that allows them to understand it.

It is essential to understand that pain is not an inevitable consequence to be endured, but can be managed and controlled at every stage of the disease. There are currently many treatment options that allow pain to be controlled and make it bearable. The choice of the appropriate and most effective treatment may involve switching from one molecule to another and changing the dosage over time to follow the evolution of your condition – changes you must make in full collaboration with your doctors.

How to track pain episodes

By using this app to record each BTcP episode, you can provide precise and continuous information to your doctors allowing them to understand the evolution of your pain and keep it correctly managed.

However, this app is not a complete solution, it was designed to require minimal effort on your part and therefore collects only essential information for each BTcP episode. We prioritised the simplicity of recording a new episode to reduce the burden of recording all your episodes. In five short steps, this app helps you record: pain type, pain location, when the episode occurred, episode duration, pain intensity, medication effect time and lastly your emotions/mood.

This information is very useful for your doctors but you should also try to be aware of the following aspects of your pain. We recommend that you take notes (write things down as they occur, it’s so easy to forget otherwise) and share them with your doctors to provide them with a complete picture.

Incident pain: occurs as a direct and immediate consequence of a movement or activity. When you experience a BTcP episode try to identify a cause and whether it was:
• voluntary, caused by a voluntary act (for example, movement),
• involuntary, caused by an involuntary act (for example, coughing),
• procedural, related to a diagnostic or therapeutic intervention.

Spontaneous pain: also known as idiopathic pain occurs without any identifiable reason.

Gradual or sudden onset: how does the pain start, is it always the same or does it change?

Pain fluctuation: is the episode pain constant or does it increase or decrease?

Relief: apart from medication do you notice anything that relieves or worsens the pain (for example, standing, lying down, sitting; distracting yourself by reading, watching TV or listening to music; staying warm, etc)?

Avoidance: is there anything that you might have noticed makes an episode worse?

Functions: what repercussions do these episodes have on your daily life? Are there things you can’t do? Do episodes affect your sleep?

  • Types of cancer pain
  • Why does cancer cause pain?
  • Why you should track pain episodes
  • How to track pain episodes
  • Glossary of medical terms