It is estimated that about 75% of patients with advanced cancer require constant analgesia. In the group of patients with cancer metastases this percentage reaches 100%. The pain is caused directly by the tumor and as a result of destruction of the surrounding tissues; infiltration of nerves, soft tissues, bones and internal organs. It is often caused by dysfunctions of other organs damaged by the growing tumor. Pain can also be a consequence of the treatment of the cancer itself. An example is tissue pain, dissected during surgery, pain generated by radiation-damaged nerves, pain associated with inflammation of tissues, caused by cancer treatments used for treating cancer or pain caused by radiation changes.
Treatment of pain, in addition to administering painkillers, should be based on an assessment of its cause, and then the implementation of such a course of action, the aim of which is to eliminate or reduce this cause. It should be remembered that the pain is felt more strongly when the patient has problems sleeping, which may be caused by the pain itself, but also occur due to depression, experiencing his illness, worrying about the fate of relatives. It is then necessary to give antidepressants, sleeping pills or sedatives. The sensation of pain is accompanied by various somatic reactions, for which the stimulation of the autonomic system is responsible. The vegetative symptoms include acceleration of heart rate, increase in blood pressure, increased sweating.
In the treatment of cancer pain, end-of-dose pain is a problem in patients treated with chronic opioids – they appear with the regression of their effects, regularly, before the next dose of a painkiller. Their presence is associated with a decrease in the therapeutic concentration of the drug due to too low a dose or faster than expected drug absorption or poorly planned therapy (too long intervals between administrations exceeding the duration of action of the opioid).
Another breakthrough pain is breakthrough. This is a sudden, transient, exacerbating pain that occurs in patients whose cancer pain is controlled by the constant administration of opioid analgesics and supportive medications.
Piercing pains are very annoying. They occur suddenly, paroxysm, grow rapidly (up to 3 minutes), are short-lived (on average about 30-minute episodes), extremely strong. They “break through” above the level of normal pain sensations. Most often they appear without a clear cause, but they can also be caused by specific situations such as movement, cough, defecation, swallowing, stress and emotions. They have the same location, range and are described similarly to basic pains. An example may be paroxysmal, short-term pain with a very high potential in patients with pancreatic cancer, or an attack of bone pain in the case of secondary lesions (metastases) in the course of a neoplastic disease. In the treatment of cancer pain, an effective scheme for the so-called analgesic ladder has been developed. The diagram distinguishes three stages of treatment intensity – depending on the level of pain perception. Pharmacotherapy according to the indications of the ladder can be effective in 70-90% of patients with cancer pain.
1 – with low intensity pain – the drug of choice are non-opioid analgesics – which include: paracetamol, metamizol, non-steroidal anti-inflammatory drugs (ibuprofen, acetylsalicylic acid, diclofenac) + possibly a supportive medicine.
2 – weak opioid drug – tramadol, codeine, dihydrocodeine + optional non-opioid analgesics from the first level of the ladder + possibly a supportive drug.
3 – with very strong pains – strong opioid drug – morphine (administered subcutaneously / orally), fentanyl in the form of a transdermal patch (patch), buprenorphine, oxycodone + optional non-opioid analgesics from the first level of the ladder + possibly a supportive drug.
In the treatment of cancer pains, anti-epileptic drugs, antidepressants and other methods are also commonly used:
- palliative treatment
- oncological rehabilitation