Cancer pain should be treated with the principle of comprehensive treatment, according to the patient’s condition and physical status, effective application of analgesic treatment, sustainable and effective elimination of pain, prevention and control of adverse drug reactions, and reduction of pain and the psychological burden caused by treatment, with a view to maximizing the quality of life of patients.
Treatment methods.
The treatment methods of cancer pain include: etiological treatment, pharmacological pain relief treatment and non-pharmacological treatment.
1. Etiological treatment. Treating the causes of cancer pain. The main causes of cancer pain are cancer itself, complications and so on. Anti-cancer treatment, such as surgery, radiotherapy or chemotherapy, is given to cancer patients, which may relieve cancer pain.
2.Drug pain treatment.
(1) Principle. According to the World Health Organization (WHO) guidelines for three-step pain relief treatment for cancer pain, the five basic principles of pharmacological pain relief treatment for cancer pain are as follows.
1. Oral drug administration. Oral administration is the most common route of drug delivery. For patients who are not suitable for oral administration, other routes of drug delivery can be used, such as subcutaneous injection of morphine, patient-controlled analgesia, and more convenient methods such as transdermal patches.
2.Medication according to the step. According to the degree of pain of patients, different strength of analgesic drugs should be used in a targeted manner.
①Mild pain: non-steroidal anti-inflammatory drugs (NSAID) can be used.
②Moderate pain: weak opioids can be used, and NSAIDs can be used in combination.
③Severe pain: strong opioids can be used and NSAIDs can be used in combination.
The use of opioids together with NSAIDs can enhance the pain relief effect of opioids and reduce the dosage of opioids. Strong opioids may also be considered for mild and moderate pain if good analgesia can be achieved without serious adverse effects. If the patient is diagnosed with neuropathic pain, tricyclic antidepressants or anticonvulsants should be preferred.
3. Timely administration of medication. Refers to the regular administration of pain medication at prescribed time intervals. Timely administration helps to maintain a stable and effective blood concentration. At present, the clinical use of controlled and slow-release drugs is becoming more and more widespread, emphasizing the use of controlled and slow-release opioid drugs as the basic medication for pain relief, and the immediate release opioid drugs can be given for symptomatic treatment when titration and outbreak pain occur.
4.Individualized drug administration. It refers to the individualized medication plan according to the patient’s condition and the dose of cancer pain relief drugs. When opioids are used, there is no ideal standard dose of opioids due to individual differences, and sufficient doses of drugs should be used according to the patient’s condition so that pain can be relieved. Also, the nature of neuropathic pain should be identified and the possibility of combined medication should be considered.
5. Pay attention to specific details. Patients using painkillers should be monitored more closely, the degree of pain relief and the organism’s reaction should be observed closely, the interactions of the combined application of drugs should be noted, and the necessary measures should be taken in a timely manner to minimize the adverse drug reactions with a view to improving the quality of life of patients.
(2) Drug selection and use method. According to the degree and nature of pain, the treatment being received and the concomitant diseases, cancer patients should reasonably choose pain-relieving drugs and auxiliary drugs, individually adjust the dosage and frequency of drug administration, and prevent and control adverse reactions, in order to obtain the best pain-relieving effect and reduce the occurrence of adverse reactions.
1.Non-steroidal anti-inflammatory drugs. Different NSAIDs have similar mechanism of action and have analgesic and anti-inflammatory effects, and are often used to relieve mild pain or combined with opioids to relieve moderate and severe pain. NSAIDs commonly used in cancer pain treatment include: ibuprofen, diclofenac, acetaminophen, indomethacin, celecoxib, etc.
The common adverse reactions of NSAIDs include: peptic ulcer, gastrointestinal bleeding, platelet dysfunction, renal impairment, hepatic impairment, etc. The occurrence of their adverse reactions is related to the dose and duration of use. The daily limit doses of NSAIDs are: ibuprofen 2400mg/d, acetaminophen 2000mg/d, celecoxib 400mg/d. When using NSAIDs, the dose of medication reaches above a certain level, increasing the dose of medication does not enhance its pain-relieving effect, but the toxic reaction of medication will increase significantly. Therefore, if long-term use of non-steroidal anti-inflammatory drugs is required, or the daily dose has reached the restrictive dosage, should consider replacing it with opioid analgesics; if it is a combination, only increase the dose of opioid analgesics.
2.Opioid drugs. It is the drug of choice for moderate and severe pain treatment. At present, the short-acting opioid drugs commonly used in cancer pain treatment are morphine immediate release tablets and long-acting opioid drugs are morphine extended-release tablets, oxycodone extended-release tablets and fentanyl transdermal patches. For the treatment of chronic cancer pain, opioid agonists are recommended. For long-term use of opioid analgesics, oral route of administration is preferred, and transdermal absorption route of administration can be used when there are clear indications.
①Initial dose titration. There are large individual differences in the efficacy and safety of opioid analgesics, so it is necessary to gradually adjust the dose to obtain the best dose, which is called dose titration. For patients using opioids for pain relief for the first time, titration should be performed according to the following principles: use morphine immediate release tablets for treatment; draw up an initial fixed dose of 5-15 mg for Q4h according to the degree of pain; if the pain is not relieved or not satisfactorily relieved after medication, the titrated dose should be given after 1 hour according to the degree of pain (see Table 1), and closely observe the degree of pain and adverse reactions. After the first day of treatment, calculate the drug dose for the next day: total fixed dose for the next day = total fixed dose for the previous 24 hours + total titrated dose for the previous day. On the second day of treatment, the calculated next day’s total fixed dose is divided into 6 oral doses, and the next day’s titrated dose is 10%-20% of the previous 24 hours’ total fixed dose. Adjust the dose day by day as indicated until the pain score stabilizes at 0-3. In case of uncontrollable adverse effects and pain intensity 4, a downward adjustment of the titration dose by 25% and re-evaluation of the condition should be considered.