Cancer

Malignant neoplasms represent a constellation of diseases arising from accumulated genetic mutations that disrupt normal cellular regulation and proliferation. The pathophysiology extends beyond the tumor itself to encompass profound systemic effects from both the disease process and its therapeutic interventions. Chemotherapeutic agents carry substantial organ toxicity that directly influences anesthetic management: anthracyclines cause dose-dependent cardiotoxicity with risk of dysrhythmias and cardiomyopathy requiring baseline echocardiography; bleomycin produces irreversible pulmonary fibrosis exacerbated by high intraoperative oxygen concentrations, necessitating careful titration to maintain saturations between 90 and 92 percent; platinum-based compounds and methotrexate compromise renal function; and vinca alkaloids trigger peripheral and autonomic neuropathy that alters neuromuscular physiology. Radiation therapy to specific anatomic regions creates additional hazards including mediastinal fibrosis with accelerated coronary disease, head and neck tissue fibrosis limiting mouth opening and causing tracheal stenosis, and thoracic radiation leading to interstitial lung disease. Paraneoplastic syndromes, occurring in approximately 8 percent of cancer patients, manifest as cross-reactive autoimmune phenomena such as Lambert-Eaton myasthenic syndrome associated with small cell lung cancer, myasthenia gravis linked to thymoma, and endocrine disturbances including syndrome of inappropriate antidiuretic hormone, ectopic Cushing syndrome, and malignancy-related hypercalcemia. Local mass effects create mechanical emergencies such as superior vena cava syndrome, spinal cord compression, and increased intracranial pressure. Preoperative assessment must evaluate immunosuppression, potential adrenal insufficiency from corticosteroid exposure, tumor lysis syndrome risk following chemotherapy initiation, and toxicities from prior treatments. Specific malignancies warrant individualized consideration: lung cancer requires pulmonary function testing with FEV1 greater than 2 liters and DLCO greater than 80 percent predicting favorable postoperative outcomes; breast cancer patients with axillary dissection face lymphedema risk necessitating avoidance of ipsilateral venous access; multiple myeloma demands careful management of hypercalcemia and prevention of pathologic fractures; and hematopoietic stem cell transplant recipients face graft-versus-host disease with multisystem involvement. Cancer pain management follows a multimodal framework incorporating acetaminophen, nonsteroidal agents particularly for osseous metastases, opioid analgesics with rotation strategies, gabapentin and tricyclic antidepressants for neuropathic components, and interventional techniques including neurolytic blockade with consideration of sympathomimetic effects.