Neoplasms and Cancer Notes

Terminology

• Differentiation
  • Each cell type differentiates and carries out particular functions.
  • The structure reflects the function of the tissue.
• Mitosis
  • Part of the cell cycle.
  • Requires genetic control—DNA and RNA.
• Mutation
  • If DNA in parent cell is altered and passed on, offspring cells will carry the mutation.
• Apoptosis
  • Programmed cell death.
  • Controlled by genetic elements.

Neoplasms

• Neoplasm or tumor
  • Cellular growth that no longer responds to normal genetic controls.
  • Cell continues to reproduce, without need for them to reproduce.
  • Deprives other cells of nutrition.
  • Neoplasms may consist of atypical or immature cells.
  • Characteristics of each tumor depend on:
    • Type of cell from which the tumor arises.
    • Unique structure and growth pattern.

Nomenclature

• Benign tumors have tissue name plus the suffix -oma (e.g., adenoma).
• Malignant tumors (cancers) have the tissue name plus the suffix -carcinoma (e.g., adenocarcinoma).
• Tumors of connective tissue are usually termed sarcomas and are often malignant.
• Several malignant tumors have unique names:
  • Hodgkin’s disease
  • Wilms’ tumor
  • Leukemia

Table of Tumor Nomenclature

Benign and Malignant Tumors

• Benign tumors
  • Usually differentiated cells that reproduce at a higher rate than normal.
  • Encapsulated.
  • Tissue damage.
    • This is a result of compression of adjacent structures.
    • It can be life-threatening in the brain.
• Malignant tumors
  • Undifferentiated, nonfunctional cells.
  • Rapid reproduction—abnormal mitotic figures.
  • Infiltrate or spread into surrounding tissue.
  • Spread to distant sites.

Table of Characteristics of Benign and Malignant Tumors

Characteristics of Benign and Malignant Tumors Visualized

• Benign Tumor
  • Slowly expanding mass
  • Relatively normal cells
  • Capsule
• Malignant Tumor
  • Irregular shape and surface
  • Abnormal cells, Irregular size and shape
  • Tissue invasion, Necrosis, Invasion of blood vessels

Malignant Tumors: Cancer

• Lack control of mitosis and do not undergo apoptosis.
• No normal organization or differentiation.
• No contact inhibition.
• Abnormal cell membranes.
• Altered surface antigens.
• Do not adhere to each other.
• Often break loose from mass.
• Invade other tissues and may spread to distant sites.
• Mass compresses blood vessels.
  • Leads to necrosis and inflammation around tumor.
• Tumor cells may secrete enzymes or hormones.
  • Break down of proteins and cells
  • Systemic effects, such as altered calcium levels.
• Inflammation and loss of normal cells
  • Lead to progressive reduction in organ integrity and function.
• Angiogenesis
  • Some tumor cells secrete growth factors.
  • Stimulate the development of new capillaries in the tumor.

Warning Signs of Cancer

1. Unusual bleeding or discharge anywhere in the body
2. Change in bowel or bladder habits (e.g., prolonged diarrhea or discomfort)
3. A change in a wart or mole (i.e., color, size, or shape).
4. A sore that does not heal (on the skin or in the mouth, anywhere)
5. Unexplained weight loss
6. Anemia or low hemoglobin, and persistent fatigue
7. Persistent cough or hoarseness without reason
8. A solid lump, often painless, in the breast or testes or anywhere on the body.

Local Effects of Tumors

• Pain
  • May be absent until very late stages.
  • Occurs when tumor is well advanced.
  • Severity depends on the type of tumor.
• Obstruction
  • Occurs when tumor compresses a duct or passageway.
  • Blood supply or lymphatic flow may be restricted
  • Digestive tract
  • Airflow in bronchi
• Tissue necrosis and ulceration
  • May lead to bleeding or infection around the tumor

Diagnostic Tests

• Routine screening
  • Essential for early detection.
  • Following treatment to detect any further tumors.
• Self-examination
  • Early detection if done consistently.
  • Breast, testicular, and skin examinations are important.
• Blood tests
  • Measure blood cell levels during treatment.
  • May detect tumor markers (e.g., PSA test)
• Radiographic, ultrasound, MRI, CT
  • Methods of visualizing changes in tissues or organs
• Cytological tests require biopsy or cell sample
  • Histological and cytological examinations to determine degree of differentiation and tumor type
  • May be tested for growth promoter sensitivities, (e.g., estrogen- dependent tumors)
  • Most dependable confirmation of malignancy
• Genomic Tumor Assessment identifies genetic mutations that are independent of heredity but only occur with the disease itself.

Spread of Malignant Tumors

• Invasion
  • Local spread
  • Tumor cells grow into adjacent tissues.
  • Example: Uterine carcinoma invades the vagina.
• Metastasis
  • Spread to distant sites
  • Via blood or lymph or other body fluids
  • Example: Carcinoma of the colon spreads to the liver.

Staging Cancer

• Essential to standardize comparative studies of treatments and outcomes.
• Used to estimate prognosis.
• Most common system used is the TMN system:
  • Size of primary tumor (T)
  • Involvement of regional lymph nodes (N)
  • Spread (metastasis) of tumor (M)

Carcinogenesis

• Process whereby normal cells are transformed into cancer cells.
• Process varies greatly with respect to time.
• Cancer is thought to be a multifactorial disease because of:
  • Environmental effects
  • Change in gene expression (heredity)
  • Infection in some cases (e.g., cervical and hepatic cancers)
• Some cancers have well-established risk factors.

Prognosis

• Cancer-free state generally defined as 5-year survival without recurrence
• Some cancers such as childhood leukemias can be considered cured after a 10- year, cancer-free period.
• Remission—no clinical signs of cancer
  • Client may experience several remissions.
• Life expectancy and death rates for specific cancers vary.