neuropathic pain when they directly invade local nerves or when they cause local edema that affects the nerves in the vicinity Tumor infiltrating an organ may cause ill-defined pain as the organ capsule becomes stretched Bone pain may signify a pathologic fracture from a tumor weakening the bone, as can occur with Ewing sarcoma or osteosarcoma The bones may also hurt due to tumor invading the bone marrow space Pain in the head and neck may result from increased ICP or tumor involvement of the meninges/cerebrospinal fluid (most common in hematologic malignancies) On the other hand, pain may be related to cancer treatment In these cases, the patient or family may report that this particular pain has been historically linked to a specific therapy A particularly challenging problem is the phantom pain that can occur after limb amputation In addition, oncology patients may experience pain of the mouth, GI tract, or even urethra as part of mucositis Pain could also represent a focal infection, complicating the patient’s compromised immune system Bone pain may reflect recent therapy with hematopoietic growth factors to stimulate neutrophil recovery after chemotherapy Radiation therapy can induce local tissue injury, which may be very painful Abdominal pain is a common complaint in cancer patients and can arise from several sources The differential diagnosis may be very wide including pancreatitis, hepatitis, cholecystitis, constipation, mucosal injury, intra-abdominal infection, and bowel obstruction (see “Hepatic and Gastrointestinal Complications of Cancer Treatment” section) Clinical Considerations Clinical Assessment An important first step in management is to explicitly address pain when taking the patient’s history Even patients who come to the ED for other reasons may have pain complicating their presentation Upon determining that a patient is in pain, according to the patient’s report as opposed to the clinician’s assessment, the emergency clinician must initiate immediate pain treatment The remainder of the history and physical examination should be used to identify the cause of the pain and to explore specific treatment for that cause Management Acetaminophen is a useful analgesic with minimal side effects for most patients, remembering to avoid the rectal route if the patient is neutropenic NSAIDs and aspirin may be effective as pain relievers but are generally avoided in this patient population due to their antiplatelet effect in the setting of frequent