Cancer may lead to pain, weight loss, fatigue, or obstruction of visceral organs. Death typically occurs as a result of inanition and organ failure. Most cancer deaths are due to metastases rather than the primary cancer.
Pain in patients with cancer frequently results from bone metastases, nerve or plexus involvement, or pressure exerted by a tumor mass or effusion. Aggressive pain management Treatment of Pain Nonopioid and opioid analgesics are the main drugs used to treat pain. Antidepressants, antiseizure drugs, and other central nervous system (CNS)–active drugs may also be used for chronic or... read more is essential in the treatment of cancer and for maintenance of quality of life.
Pleural effusions Pleural Effusion Pleural effusions are accumulations of fluid within the pleural space. They have multiple causes and are usually classified as transudates or exudates. Detection is by physical examination,... read more 
should be drained if symptomatic and monitored for reaccumulation. If the effusion reaccumulates rapidly, thoracostomy tube drainage How To Do Tube and Catheter Thoracostomy Surgical tube thoracostomy is insertion of a surgical tube into the pleural space to drain air or fluid from the chest. Pneumothorax that is recurrent, persistent, traumatic, large, under tension... read more 
and sclerosing agents or repeated catheter drainage should be considered.
Spinal cord compression Spinal Cord Compression Various lesions can compress the spinal cord, causing segmental sensory, motor, reflex, and sphincter deficits. Diagnosis is by MRI. Treatment is directed at relieving compression. (See also... read more 
can result from cancer spread to the vertebrae and requires immediate surgery or radiation therapy. Symptoms may include back pain, lower extremity paresthesias, and bowel and bladder dysfunction. Diagnosis is confirmed by CT or MRI.
Venous thrombosis (clots in the veins) in the lower extremities leading to pulmonary emboli Pulmonary Embolism (PE) Pulmonary embolism (PE) is the occlusion of pulmonary arteries by thrombi that originate elsewhere, typically in the large veins of the legs or pelvis. Risk factors for pulmonary embolism are... read more 
are frequent in patients with pancreatic, lung, and other solid tumors and in patients with brain tumors. Tumors produce procoagulants, such as tissue factor, leading to excess clot formation, particularly in patients undergoing surgery.
Metabolic and immune consequences of cancer can include hypercalcemia, hyperuricemia, increased ACTH production, antibodies that produce neurologic dysfunction, hemolytic anemia, and many other paraneoplastic complications Paraneoplastic Syndromes Paraneoplastic syndromes are symptoms that occur at sites distant from a tumor or its metastasis. Although the pathogenesis remains unclear, these symptoms may be secondary to substances secreted... read more 
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