لخّصلي

Glossary
Oncology: Oncology is the study of tumors
Hyperplasia: increase in the number of cells of a tissue
Tumor: Abnormal mass of tissue produced by progressive, unlimited,
purposeless proliferation of cells.
Cancer: is defined as a group of diseases characterized by the abnormal
growth and spread of cells. Cell division in cancer is both abnormal and
uncontrolled.
Carcinogenesis: process of transforming normal cells into malignant cells
Metastasis: spread of cancer cells from the primary tumor to distant
sites
Thrombocytopenia: decrease in the number of circulating platelets;
associated with the potential for bleeding
Alopecia: hair loss
Classification of tumor
 Benign: not cancerous; benign tumors may grow but are unable to
spread to other areas
 Malignant: A tumor which always invades the surrounding tissues
and give metastasis.
■ Characteristics of Benign and Malignant Neoplasm
Character Benign Malignant
Shape Capsulated Not capsulated
Size Usually smaller than malignant Rapid increase in size
Degree of
differentiation
Well- differentiated Cell show variable loss of
differentiation
Mode of growth Grows by expansion, does not
infiltrate
Grows at the periphery,
infiltrate and destroy the
surrounding tissue
Rate of growth Generally slow Grow rapidly
Metastasis Absent Present
Recurrence Not recurrent Recurrent
Tissue destruction No tissue destruction Extensive tissue destruction
Effect Insignificant effect except in vital
organ
Dangerous effect
Benign tumor complications
 Pressure effect: meningioma press on brain.
 Obstruction of a hollow organ: bronchial adenoma causing
bronchus obstruction.
 Ulceration and hemorrhage.
 Infection: papilloma of bladder.
 Rupture of cyst neoplasm: cyst adenoma of ovary.
 Hormone production.
 Malignant change: adenoma of colon----adenocarcinoma.
Epidemiology of cancer
Although cancer affects every age group, most cancers occur in people
older than 65 years of age. Overall, the incidence of cancer is higher in
men than in women and higher in industrialized sectors and nations.
Development of Cancer
Carcinogenesis and oncogenesis are other names for cancer
development. The process of changing a normal cell into a cancer cell is
called malignant transformation. This process occurs through four stages:
initiation, promotion, progression and metastasis
1 - The initiation process involves carcinogens (factors that contribute
the development of cancer such as chemicals, physical factors) that alter
the genetic structure of DNA within cells.
2- During promotion, repeated exposure to carcinogens transforms the
genetic information so that cells begin to produce mutant (malformed)
cell population.
3- Progression: This stage is characterized by increased growth rate of
the tumor, increased invasiveness.
4- Metastasis is spread of the cancer to a distant site
 Etiology and risk factors
In general, tumors are not attributable to a single cause

1. Biological factors:
   ♦ Viruses: viruses play a significant role in weakening immunologic
   defenses against neoplasms e.g. papilloma virus, and hepatitis B virus.
   ♦ Genetic and familial factors:
    Abnormal chromosomal patterns have been associated with extra
   chromosomes, too few chromosomes, or translocated
   chromosomes.e.g. Leukemia, meningiomas.
    Approximately 5% to 10% of cancers of adulthood and childhood
   display a familial predisposition.


2. Chemical factors: Smoking, alcohol, uranium


3. Physical Agents
   ♦ Radiation: exposure to sunlight or Gamma and X- ray.
   ♦ Chronic irritation or inflammation.


4. Dietary Factors
   ♦ The risk for cancer increases with long-term ingestion of carcinogens or
   co-carcinogens or chronic absence of proactive substances in the diet.
   Dietary substances associated with an increased cancer risk include fats,
   alcohol, salt-cured or smoked meats and a high caloric dietary intake.
   ♦ Obesity is associated with endometrial cancer and possibly
   postmenopausal breast cancers. Obesity may also increase the risk for
   cancers of the colon, kidney, and gallbladder.


5. Hormonal Agents
   Disturbances in hormonal balance either by the body’s own
   (endogenous) hormone production or by administration of (exogenous)
   hormones.

• E.g. Cancers of the breast, prostate, and uterus are thought to depend on
  endogenous hormonal levels for growth.


• Oral contraceptives and prolonged estrogen replacement therapy.

6. Age


7. Defects of immune system. 8. Stress
    Warning signs of cancer (Caution)
    Change in bowel or bladder habits
    A sore that does not heal
    Unusual bleeding or discharge from anybody orifice
    Thickening or a lump in the breast or elsewhere
    Indigestion or difficulty in swallowing
    Obvious change in a wart or mole
    Nagging cough or hoarseness
   ■ Tumor staging
   ♦ Tumor stage describes the extent of the disease.
   ♦ Staging generally considers three important factors:
    Local size of primary tumor
    Presence or absence of lymph node involvement and its extent
    Presence or absence of distant metastases
   Staging of cancer (Clinical staging):
   The clinical staging classification system determines the extent of the
   disease process of cancer by stages:
    Stage 0: Cancer in situ.
    Stage I: Tumor limited to the tissue of origin; localized tumor growth.
    Stage II: Limited local spread.
    Stage III: Extensive local and regional spread.
    Stage IV: Metastasis
   ■ Metastatic mechanism of cancer
    Another definition: development of secondary malignant implants
   away from the primary tumor.