Resumen
Opioids, such as morphine, are strong pain killing medicines. Patients with cancer often need opioids to manage their pain. Although they might be helpful for pain control, opioids have side effects. Some of these side effects are obvious such as constipation and confusion. Other side effects are less overt, such as effects on the immune system and other effects on cancer growth. There have been studies in patients with advanced cancer which show that patients taking opioids have a shorter survival than patients not taking opioids. There are other differences in these groups of patients which might also account for the differences in survival. These include the possibility that patients needing opioids might have more aggressive cancers which cause more pain, which is why this group of patients take more opioids. It is also possible that the more aggressive cancer is what shortens survival. Future studies are needed to understand the cause of the effects of the underlying cancer type, pain, specific opioids, and survival. Until this is better understood, opioids should continue to be used to control pain in patients with cancer.