Cancer pain is a worldwide problem, especially in advanced cancer patients, where pain is one of the main presenting symptoms. Cancer pain treatment is an important element in cancer treatment, and being able to treat pain effectively will undoubtedly help patients adhere to complete the complete radiotherapy and chemotherapy process, and it is also the only way to end-of-life well-being and improve the quality of life for advanced patients.
I. Drug therapy
From the perspective of pharmacology, drugs for cancer pain are divided into 3 major categories.
1. non-opioid drugs, which are used for mild to moderate pain.
2.Opioid drugs, divided into 2 kinds of weak and strong, which are used to relieve moderate to severe pain respectively, with morphine as its representative drug.
3.Adjunctive drugs, including anti-inhibitors, anxiolytics, anticonvulsants and other drugs such as corticosteroids, which are effective for specific types.
II. Radiotherapy
The relief rate of radiotherapy for pain caused by cancer compression or infiltration of nerves is 70%-85%. If the primary foci are sensitive to radiotherapy, the effect is better. Especially for limited bone metastasis, local radiotherapy can not only suppress or even kill the tumor, but also greatly reduce the pain, which has its unique therapeutic effect. The indications of radiotherapy for pain relief are mainly metastatic bone tumor, spinal metastasis, compression of spinal nerve root by tumor, brain tumor, lung cancer invading brachial plexus nerve, stomach and pancreatic cancer invading posterior peritoneum, etc.
Generally speaking, if the patient is convenient, the most suitable irradiation method is tumor absorption dose of 30Gy/2W/10F. 80%-90% of the patients can get longer lasting pain relief, and more than 70% of the patients have a remission period of 3 months, and maintain a satisfactory quality of life and can basically take care of themselves. Among the patients who survive for more than 1 year, 50-60% of them have sustained pain relief until death.
3.Surgical treatment
Surgery plays an important role in the treatment of cancer pain. Surgery is a necessary and effective treatment method for obstructive pain caused by tumor compression and stimulation.
1.Anesthesia methods: There are 5 main types of anesthesia methods.
(1) peripheral nerve block.
(2) myofascial trigger point injection.
(3) Autonomic nerve block.
(4) intrathecal nerve block.
(5) Nitrous oxide drug anesthesia.
Local injection of local anesthetics to block peripheral nerve conduction can relieve limited cancer pain, which is simple and feasible. If local anesthetics are ineffective, anhydrous alcohol and phenol can be considered to destroy the nerves for the purpose of nerve destructive blockade for pain relief (anesthesia surgery). For visceral cancer pain, using abdominal ganglion conduction block is effective; for cancer pain infiltrating brachial plexus and lumbosacral plexus, and head, neck and face cancer pain, doing sympathetic ganglion conduction block is effective. Among all cancer pain patients, about 20% of them need to do nerve destructive block, whose effective pain relief time is from several hours to several months, with an average of 3-6 months. Therefore, in estimating the survival period of cancer pain patients over 6 months, it is not advocated to do nerve destructive block, otherwise it will be more difficult to deal with the pain in the future.
2.Neurosurgical methods: They can be divided into 3 major categories.
(1) nerve destruction methods.
(2) nerve stimulation methods.
(3) Excision or severance of peripheral nerves and nerve roots are used to relieve pain treatment in the felt area.
There are 3 forms of neurosurgical relief of cancer pain.
(1) implantation of drug pumps.
(2) neurectomy.
(3) neurostimulation.
Among neurectomy, percutaneous anterolateral spinal column resection is most commonly used for unilateral lower limb pain caused by rectal and pelvic tumor invasion of the nerve plexus, and survival is estimated to be ≤2-3 years. Thalamotomy to block thalamic nociceptive conduction pathway or pituitary gland removal is almost all effective for breast cancer pain. For cancer pain with systemic bone metastases, chemical pituitary resection can provide relief to 80% of patients, but it often causes complications such as uveitis and cerebral nerve palsy. Deep nerve stimulation is effective for both central and afferent nerve pain without damaging motor function, so it has certain application prospects.
3. Orthopedic approach: When the frontal and lateral radiographs show more than half of the bone cortical destruction, pathological fracture will occur in about 2/3 of patients or even if there is no serious bone cortical destruction but the long bone bone destruction is more than 3 cm, fixation (including splinting, suspension, etc.) should be given. Once pathological fracture occurs, internal or external fixation should be performed immediately. Bone tumors of the limbs can be repaired and reconstructed after resection of cancerous segments, which can restore most or partial functions of limbs, eliminate and reduce pain, reduce disability rate, prolong life and improve survival quality.
IV. Chemotherapy
Chemotherapy is mainly applied to patients with multiple bone metastases. Especially for pain caused by compression or infiltration of nerve tissue caused by chemotherapy-sensitive tumors such as lymphoma, small cell lung cancer, leukemia, etc., it can show rapid effect. For patients with intravertebral tumor metastasis, long-term use of high-dose analgesics can hardly be effective, epidural infusion of methotrexate with hypertonic saline is used to make the anti-cancer drug come into direct contact with the tumor and kill the cancer cells within minutes. neuralgia.
V. Radioisotope therapy
With the development of nuclear medicine, osteophilic radionuclides are increasingly used in the treatment of bone metastatic cancer pain relief. At present, 153Sm-EDTMP (153 samarium monoethylenediamine tetramethylphosphonic acid) is widely used clinically to treat bone metastases, especially pain caused by multiple early bone metastases, and can inhibit the development of tumor with less side effects. Satisfactory effect of bisphosphonate nucleotide in treating cancerous pain of multiple bone metastases.
VI. Cellular analgesia and gene therapy
Cellular analgesic therapy is to implant in vitro cultured autologous cells or cell lines into the body, and through these cells, which are similar to “biological micro-pumps”, they can continuously secrete analgesic substances to relieve pain or increase the pain threshold. These transplanted cells can secrete antinociceptive proteins, antinociceptive modulators, enzymes or signal transduction factors that enhance the expression of antinociceptive proteins. In pain research, there are two main aspects of gene therapy, namely upregulation of antinociceptive gene expression and downregulation of pain gene expression, which specifically interfere with the biological behavior of pain for therapeutic purposes.