CANCER PATHOPHYSIOLOGY

Cancer is a complex and heterogeneous group of diseases characterized by uncontrolled cell proliferation, invasion of surrounding tissues, and potential metastasis to distant organs. This chapter provides an in-depth overview of cancer pathophysiology, emphasizing the cellular and molecular mechanisms that drive tumor initiation, progression, and dissemination. Topics covered include the breakdown of normal cell cycle regulation, genetic and epigenetic mutations, the role of the tumor microenvironment, angiogenesis, and metastatic pathways. Tumor classification, grading, and staging systems are examined to illustrate their importance in treatment planning and prognosis. Major cancer treatment modalities—including chemotherapy, targeted therapies, and emerging immunotherapies—are discussed along with common complications and supportive care interventions. Oncology care extends beyond tumor destruction to encompass symptom management, psychosocial support, patient education, and palliative care. A comprehensive understanding of cancer biology is essential for clinicians to recognize disease patterns, implement evidence-based therapies, and provide holistic and compassionate care to patients throughout the cancer trajectory.