Pain medicine also known as Interventional Pain Medicine, the main objectives of this medical area are to reduce and control pain, helping the patient to improve their productivity and quality of life, aspects that are impaired in cases of chronic pain. The pain doctor can determine what are the best resources to ensure a treatment that meets the main needs and possibilities in each case.
In cancer, pain can be the first and only symptom and can be felt in all stages of the disease, depending on the type of tumor and treatment, which includes surgery, radiotherapy, and chemotherapy. According to the Brazilian Society for the Study of Pain, it is estimated that about 1/3 of cured cancer patients will have chronic pain. Therefore, besides being part of the treatment, its control is very important to ensure the patient’s quality of life.
Types of pain in oncology
Oncologic pain – Most cases of pain occur when a tumor presses on the bones, nerves, and organs of the body. Patients with advanced disease are more likely to experience pain.
Spinal cord compression – When a tumor invades the spine, it can put pressure on the spinal cord. This is called spinal cord compression. The first sign of compression is usually pain in the back of the neck or sore throat, sometimes with numbness or weakness in an arm or leg. Coughing, sneezing, or performing other movements often aggravate the pain.
Bone pain – This type of pain can happen when the disease spreads to the bones. Treatment is aimed at controlling cancer and protecting the affected bones. Radiation therapy is done to treat the affected bone. Bone pain can also occur as a side effect of medications such as growth factors or colony-stimulating factors.
Surgical pain – Surgery is performed to treat cancers that have grown as solid tumors, but other treatments such as chemotherapy or radiation therapy may also be administered concomitantly. Depending on the type of surgery, pain is to be expected. However, medications are prescribed so that the patient does not have to feel pain. Pain due to surgery can last from a few days to a few weeks, depending on the type and extent of the surgical procedure.
“Phantom” pain – This is a long lasting effect of surgery, in addition to the usual surgical pain. If you have had an arm, leg, or even a breast removed, you may still feel pain or have other unusual or unpleasant sensations that seem to be coming from the missing body part. It is not clear why this happens, but phantom pain is real, not imagination.
Pain from other cancer treatments – Some of the side effects caused by chemotherapy and radiation therapy can cause pain. Pain can even lead to treatment discontinuation if not managed well.
Peripheral neuropathy – This condition refers to pain, burning, tingling, numbness, weakness, difficulty walking, or strange sensations in the hands, arms or legs, and feet. Peripheral neuropathy can be caused by certain types of chemotherapy drugs, although it can also be due to vitamin deficiencies, cancer, and other health problems such as diabetes and infections.
Mouth sores – Chemotherapy can cause sores and pain in the mouth and throat (stomatitis or mucositis). The pain can be so severe that the patient is unable to eat or even has difficulty speaking.
Mucositis and other radiation damage – Pain from radiation treatment depends on what part of the body has been irradiated. Radiation therapy can cause skin burns, mucositis (thrush), and scarring, which can cause pain. The throat, bowel, lungs, and bladder are also susceptible to damage from radiation therapy.
Pain from procedures and tests – Some tests performed to diagnose cancer and evaluate the tumor’s response to treatment can be painful. Concern about pain should not prevent you from having the test, as it can be treated after the procedure.
The patient must have access to an individualized analgesic treatment, planned by a multidisciplinary team, in partnership with the oncologist. There are several techniques available, such as analgesic/anesthetic blocks, neurosurgery, physiotherapy, acupuncture, implantation of analgesic devices, and manufacturing of orthoses and prostheses.
On a scale, the intensity and nature of the physical suffering and its response to treatments are assessed. In patients with chronic pain, biological, psychological, spiritual, and social support can also help to cope with suffering. According to the World Health Organization (WHO) Analgesic Ladder in 1986, recommends, based on the severity of pain and the effectiveness of analgesics, the following steps should be adopted:
Step 1: Light. Use non-opiate painkillers that can generally be purchased without a prescription;
Step 2: Moderate. If the non-opioid drug does not provide relief, a weak opioid is introduced.
Step 3: Intense. If treatment with the step 2 analgesics is ineffective, strong opioid drugs should be prescribed. According to the WHO, the gold standard for the treatment of cancer pain is morphine, as it is a cheap and affordable drug.