Oncology Nursing: Cancer Overview

Week 15 - Oncology Nursing: Cancer

• Cancer is a complex of diseases where normal cells mutate into abnormal cells, harming and destroying the host.
• Key characteristics of cancer include uncontrolled growth and spread of abnormal cells, proliferation (rapid cell division), and metastasis (spread to other organs).
• Oncology is the branch of medicine that studies, detects, treats, and manages cancer and neoplasia.
• Neoplasia involves uncontrolled growth of abnormal cells; benign tumors are well-differentiated, slow-growing, encapsulated, and non-invasive; malignant tumors are undifferentiated, show erratic growth, are invasive, and metastasize.
• Benign tumors have a low malignant potential and are difficult to detect.
• Malignant tumors are characterized by anaplasia (hallmark of neoplasm), meaning abnormal or non-functional cells).

Tumor Naming & Classifcation

• Tumors are named according to their origin (cell type) and structure. Naming suffixes are used (e.g., -oma, -carcinoma, -sarcomas), used for benign or malignant tumors.
• Examples: hepatoma (liver), osteoma (bone), myoma (muscle).

The Cell Cycle

• Cells grow and divide in a cyclic manner
• amount of time required for a cell to go from one mitosis to another is called the Cell Cycle Time
• cells have different characteristics throughout the cycle (labiles, stable, permanent), the time for the cell to double is called doubling time.

Cancer Theories

• Cellular transformation and derangement: Normal cells can be transformed into cancer cells due to exposure to different external factors such as chemical, viruses, radiation, or other environmental hazards.

• Specifically, other malignant transformations result from activation of oncogenes or inactivation of tumor suppressor genes.

Fundamental Changes in Malignancy

• Self-sufficiency in growth signals: Tumors can proliferate without external stimuli and produce growth factors.
• Insensitivity to growth inhibitory signals: Tumor suppressor genes do not inhibit cell growth effectively, allowing uncontrolled growth.
• Evasion of apoptosis: Cancer cells can avoid programmed cell death.
• Defects in DNA repair: Errors in DNA repair mechanisms can result in DNA damage or instability.
• Limitless replication potential: Cancer cells have the ability to divide continuously, despite normal cells only dividing a certain number of times.

How Cancer Spreads

• Most common routes include lymphatic, hematogenous, and direct spread.
• Malignant tumors can metastasize by invading nearby tissues or spreading through the bloodstream or lymph (metastasis cascade).

Cancer Warning Signs

• Unusual bleeding or discharge, Lumps, thickening, or changes in moles/warts, indigestion, difficulty in swallowing, hoarseness, unexplained anemia, or weight loss.