Comprehensive Study Notes: Oncology and Cancer Terminology

Oncology: Introduction and Overview

Definition and Scope

Oncology is the medical specialty focused on the study, diagnosis, and treatment of cancer. Unlike other specialties, oncology is not limited to a single body system, as cancer can arise in any tissue or organ. The field encompasses the anatomy and physiology of cancer cells, laboratory and diagnostic tests, medical and surgical procedures, and pharmacological treatments.

Cell Structure and Function

Structures of a Normal Cell

Cells are the smallest independently functioning units in the body, capable of reproduction through division. Each cell contains specialized structures (organelles) that perform essential functions such as nutrient uptake, energy production, protein synthesis, and defense against pathogens.

• Cell membrane: Regulates entry and exit of substances.

• Nucleus: Contains genetic material (chromosomes).

• Nucleolus: Site of ribosome synthesis.

• Mitochondrion: Produces cellular energy (ATP).

• Endoplasmic reticulum: Synthesizes proteins and lipids.

• Golgi apparatus: Modifies and packages proteins.

• Lysosome: Digests cellular waste.

• Ribosomes: Sites of protein synthesis.

• Cytoplasm: Gel-like substance containing organelles.

Genetic Material: Chromosomes, DNA, and Genes

Chromosomes are paired structures within the nucleus, each containing a long DNA molecule. Humans have 46 chromosomes (23 pairs). Genes are segments of DNA that encode instructions for making proteins, which determine cell structure and function.

Cell Division: Normal and Cancerous

Normal Cell Division

Normal cells divide by mitosis in an orderly manner, typically in response to growth signals or tissue repair needs. Suppressor genes in DNA inhibit excessive cell division, maintaining tissue homeostasis. Meiosis is a specialized division producing gametes (sperm and ova) with half the chromosome number (23), ensuring genetic diversity.

Cancer Cell Division and Growth

Cancer cells arise when normal regulatory mechanisms fail. They may lose differentiation (specialized function), revert to an immature state (anaplasia), and divide uncontrollably. Key terms include:

• Differentiation: Process by which cells become specialized.

• Undifferentiation: Loss of specialized features; cells appear immature.

• Hyperplasia: Increased number of normal cells.

• Dysplasia: Abnormal cell growth and arrangement.

• Anaplasia: Complete loss of differentiation; cells are primitive.

Causes of Cancer

Etiology

Cancer can be caused by a variety of factors, including environmental carcinogens, pathogens, and hereditary mutations. Carcinogens include chemicals, radiation, and certain drugs. Pathogens such as bacteria and viruses can also initiate cancerous changes. Inherited genetic mutations (e.g., in tumor suppressor genes) increase cancer risk.

Incidence and Epidemiology

Cancer Diagnosis Across the Lifespan

The risk of developing cancer increases with age. While cancer is rare in children and young adults, incidence rises sharply in older populations. Nearly 40% of people will be diagnosed with cancer at some point in their lives.

Medical Terminology in Oncology

Key Terms and Definitions

• Anaplasia: Condition where mature, differentiated cells become undifferentiated and cancerous.

• Carcinoid tumor: Slow-growing tumor, often in the digestive tract, rarely metastasizes.

• Carcinomatosis: Presence of cancerous tumors at multiple body sites.

• Dysplasia: Abnormal cell size, shape, or organization; not yet cancerous.

• Lymphadenopathy: Enlarged lymph nodes, often due to trapped cancer cells.

• Precancerous: Abnormal cells/tissues not yet fully cancerous.

Characteristics of Cancer Cells and Tumors

Eight Hallmarks of Cancer Cells

Cancer cells differ from normal cells in several key ways:

1. Do not contribute to normal body function.

2. Are undifferentiated and lack specialized function.

3. Are disorganized in arrangement.

4. Divide more rapidly than normal cells.

5. Form irregular, unencapsulated solid tumors.

6. Induce angiogenesis (growth of new blood vessels).

7. Are invasive, infiltrating surrounding tissues.

8. Can metastasize (spread) to distant sites via blood or lymph.

Warning Signs and Progression of Cancer

Warning Signs

• Change in bowel or bladder habits

• Non-healing sores

• Unusual bleeding or discharge

• Lumps or thickening

• Indigestion or swallowing difficulty

• Changes in warts or moles

• Persistent cough or hoarseness

• Unexplained anemia or weight loss

Progression Terms

• Neoplasm: Any new, abnormal tissue growth (benign or malignant).

• Metastasis: Spread of cancer cells to distant sites.

• Remission: Period with no cancer symptoms or signs.

• Relapse: Return of cancer after improvement.

• Palliative care: Symptom management when cure is not possible.

Classification of Cancers by Body System

Common Cancers and Their Systems

Cancer	Body System
Bladder cancer	Urinary
Brain cancer	Nervous
Breast cancer	Female genital
Colon cancer	Gastrointestinal
Leukemia	Blood
Liver cancer	Gastrointestinal
Lung cancer	Pulmonary
Lymphoma	Lymph nodes
Melanoma	Skin (melanocytes)
Osteosarcoma	Skeletal
Ovarian cancer	Female genital
Renal cell cancer	Urinary
Retinoblastoma	Eye
Rhabdomyosarcoma	Muscular
Stomach cancer	Gastrointestinal
Testicular cancer	Male genital
Thyroid cancer	Endocrine
Wilms tumor	Urinary

Types of Cancer

Cancer of Blood Cells and Lymphatic Tissue

• Leukemia: Cancer of white blood cells (leukocytes).

• Lymphoma: Cancer of lymph nodes or lymphocytes (e.g., Hodgkin and Non-Hodgkin lymphoma).

• Multiple myeloma: Cancer of plasma cells in bone marrow.

Carcinoma

Carcinomas are cancers of epithelial cells, found in skin or mucous membranes. Subtypes include:

• Adenocarcinoma: Cancer of glandular epithelial cells (e.g., breast, liver).

• Bronchogenic carcinoma: Cancer of bronchial mucous membranes.

• Endometrial carcinoma: Cancer of uterine lining.

• Small cell carcinoma: Small, round/oval lung cancer cells.

• Squamous cell carcinoma: Cancer of flat skin cells, often sun-exposed.

• Transitional cell carcinoma: Cancer of urinary tract lining.

Embryonal Cell Cancers (Children)

• Hepatoblastoma: Liver cancer in children.

• Neuroblastoma: Nerve cell cancer in children.

• Retinoblastoma: Retinal cancer in children.

• Wilms tumor: Kidney cancer in children.

Sarcoma

Sarcomas are cancers of connective tissues (muscle, bone, cartilage, fat, nerves). They grow rapidly and often metastasize via the bloodstream.

• Angiosarcoma: Blood or lymph vessel cancer.

• Chondrosarcoma: Cartilage cancer.

• Kaposi sarcoma: Skin/subcutaneous tissue cancer, common in immunocompromised patients.

• Leiomyosarcoma: Smooth muscle cancer.

• Liposarcoma: Fatty tissue cancer.

• Osteosarcoma: Bone cancer.

• Rhabdomyosarcoma: Skeletal muscle cancer.

Laboratory and Diagnostic Procedures

Blood Tests

• Alpha fetoprotein (AFP): Marker for liver, ovarian, or testicular cancer.

• BRCA1/BRCA2: Genetic tests for breast/ovarian cancer risk.

• Beta-2 microglobulin: Marker for leukemia, lymphoma, multiple myeloma.

• Cancer antigens (CA 15-3, 27-29, 125): Monitor breast/ovarian cancer treatment.

• Carcinoembryonic antigen (CEA): Marker for colon, stomach, lung, pancreas cancer.

• Complete blood count (CBC): Counts blood cell types.

• Human chorionic gonadotropin (HCG): Marker for ovarian/testicular cancer.

• Prostate-specific antigen (PSA): Marker for prostate cancer.

Cytology Tests

• Bone marrow aspiration: Diagnoses blood cancers.

• Cologuard®: DNA test for colon cancer in stool.

• Exfoliative cytology: Examines cells from secretions or tissue scrapings.

• Frozen section: Rapid intraoperative tissue diagnosis.

• Grading and staging: Classifies cancer by cell appearance and spread.

• HER2/neu: Tumor marker test for certain cancers.

• Karyotype: Chromosome analysis for abnormalities.

• Oncogenomics: Studies cancer-related gene mutations.

• Receptor assays: Measures hormone receptor status in breast cancer.

Urine Tests

• Urinalysis (UA): Detects cancer markers such as Bence Jones protein, VMA, and 5-HIAA.

Radiology and Nuclear Medicine Procedures

• Computerized axial tomography (CAT/CT): X-ray imaging for tumor location and metastasis.

• Lymphangiography: X-ray with contrast dye to visualize lymphatic system.

• Magnetic resonance imaging (MRI): Uses magnetic fields and radio waves for detailed images.

• Mammography: X-ray imaging of the breast.

• Scintigraphy: Uses radioactive drugs and gamma camera for imaging.

• Ultrasonography: Uses sound waves to distinguish cysts from solid tumors.

Cancer Treatments

Chemotherapy

Chemotherapy uses drugs to kill or inhibit cancer cells. Types include:

• Alkylating agents: Break DNA strands.

• Angiogenesis inhibitors: Block new blood vessel growth.

• Antimetabolites: Block DNA synthesis.

• Biological response modulators: Stimulate immune response.

• Enzyme drugs: Deprive cancer cells of essential amino acids.

• Demethylating agents: Inhibit abnormal DNA methylation.

• Hormonal drugs: Alter hormonal environment.

• Kinase inhibitors: Block cell division enzymes.

• Mitosis inhibitors: Disrupt cell division.

• Monoclonal antibodies: Target specific cancer cell antigens.

Radiation Therapy

Radiation therapy uses high-energy waves or particles to damage cancer cell DNA. It can be delivered externally (external beam radiotherapy) or internally (brachytherapy, intravenous radiotherapy). Some cancers are radiosensitive, while others are radioresistant.

Medical and Surgical Procedures

• Immune cell therapy: Uses patient's own immune cells to attack cancer.

• Photodynamic therapy: Uses light-activated drugs to kill cancer cells.

• Biopsy (Bx): Removal of tissue for diagnosis (core needle, excisional, fine-needle, incisional, punch, sentinel node).

• Bone marrow harvest/transplantation: Replaces destroyed marrow with donor cells.

• Cryosurgery: Freezes and destroys small tumors.

• Debulking: Removes part of a large tumor.

• Electrosurgery: Uses electrical current to destroy tumors.

• En bloc resection: Removes tumor and surrounding tissue as a block.

• Endoscopy: Visualizes and biopsies internal tissues.

• Excision: Removes all or part of a tumor.

• Exenteration: Removes tumor and nearby organs.

• Exploratory laparotomy: Opens abdomen to explore for cancer.

• PICC line insertion: For chemotherapy administration.

• Lumpectomy: Removes small breast tumor with margin.

• Lymph node dissection: Removes lymph nodes for cancer staging.

• Mohs surgery: Removes skin cancer layer by layer.

• Percutaneous radiofrequency ablation: Destroys small tumors with heat.

• Radical resection: Removes tumor, lymph nodes, and surrounding tissue.

Abbreviations in Oncology

Abbreviation	Definition
AFP	Alpha fetoprotein
BRCA	Breast cancer gene
Bx	Biopsy
CAT, CT	Computerized axial tomography
CBC	Complete blood count
CEA	Carcinoembryonic antigen
HCG	Human chorionic gonadotropin
HER2	Human epidermal growth factor receptor 2
MRI	Magnetic resonance imaging
NED	No evidence of disease
PICC	Peripherally inserted central catheter
PR	Progesterone receptor
PSA	Prostate-specific antigen
TNM	Tumor, nodes, metastases
VMA	Vanillylmandelic acid