[Intractable cancer pain as a reason for referral : Analysis of pain etiology and previous drug treatment.].

Many studies have demonstrated that cancer pain can be relieved in most cases by suitable analgesic medication. Patients with a diagnosis of "intractable cancer pain", however, are referred to our pain clinic nearly every day. A retrospective study of 1140 patients was therefore performed to evaluate the pain mechanisms and whether analgesic pretreatment had been adequate. Half of the patients (53%) were suffering from pain at more than one site. The most frequent locations were the back (36% of the patients), abdomen (30%), and the thoracic (22%) region. The main pain etiologies were compression or infiltration of pain-sensitive structures by the tumor (84% of the patients), and less frequently oncological treatment (18%), debilitating disease (10%), or causes unrelated to tumor or therapy (9%). Pain could be classified with almost equal frequency as neuropathic, visceral, soft tissue-related, or bone-related. Upon admission to our pain clinic, most patients (86%) indicated pain of severe intensity. The principal causes for the inadequacy of the analgesic pretreatment were: failure to prescribe analgesics (10% of the patients), irregular intake schedule or prolonged intervals between applications (66%), underdosage of nonopioid analgesics (27%) or opioids (42%), and withholding of nonopioid analgesics (30%), strong opioids (14%), or co-analgesic drugs (17%), although their prescription was indicated. The severe pain was thus caused in many patients by simple mistakes in the prescription of analgesics. Terms like "intractable" should be used with caution when referring to cancer pain because they are often unreflected and can make patients and physicians feel helpless or insecure.