Chronic pain has gone from being a symptom to a disease of great complexity, since it not only affects the physical well-being of the patient, but also interacts in a complex way with psychological and social factors. The patient not only feels the pain; the affected person suffers, sees how his or her quality of life is dramatically altered and how his or her daily activities, even the simplest ones, are disturbed. On a social level, his or her environment also suffers. In cancer pain this is compounded by the patient’s preoccupation with his or her disease.
In recent decades, we have advanced significantly in our understanding of the basic mechanisms of pain, and both pharmacological treatments with new analgesics and interventional techniques have expanded enormously. New technologies have been developed, such as radiofrequency, spinal cord stimulation or implantable systems (mechanical or electronic), which, with radiological assistance, are performed accurately and safely, increasing the number of techniques available to control pain.
Since our first publications, with the only morphine derivatives existing 30 years ago, such as Brompton Solution or controlled-release oral morphine, we have gone on to have a wide range of opioids available by all routes, such as transdermal, buccal and nasal. We also have opioids with almost immediate action for breakthrough pain and implantable systems for the continuous administration of opioids, alone or associated with other drugs such as local anesthetics or clonidine via the spinal route.
There are what we call interventional techniques, which are image-guided punctures for the infiltration of a specific medication in order to block the nerve ending causing the pain. They are very useful when pharmacological treatment fails, examples of which are the celiac plexus block in pancreatic tumors; vertebroplasty in metastatic vertebral fractures; continuous nerve blocks in plexus compression or spinal implantable systems, which allow much smaller doses of opioids to be administered directly into the spinal space, thus obtaining greater analgesia with fewer side effects.