Cancer

Cancer 150 150 Tony Guo
  • Oncofetal antigens
    • Found on tumor cell surfaces, inside tumor cells, and fetal cells
  • Examples of oncofetal antigens
    • Carcinoembryonic antigen (CEA)
      • On cancer cells of GI tract
      • Normal cells (fetal gut, liver, and pancreas)
    • α-Fetoprotein (AFP)
      • Malignant liver cells and fetal liver cells
    • CA-125 (ovarian carcinoma)
    • CA-19-9 (pancreatic and gallbladder cancer)
    • PSA (prostate cancer)
    • CA 15-3, CA 27-29, HER-2 (breast cancer)
    • kRAS (colon cancer oncogenes)
    • EGFR (lung cancer)

 

Benign vs Malignant Neoplasms

  • Tumors can be classified as benign (well differentiated) or malignant (range from well differentiated to undifferentiated.). 
  • Tumors can be classified according to 
    • Anatomic site, 
    • Histology (grading)
    • Extent of disease (staging). 
  • Tumor classification systems provide a standardized way to 
    • Communicate the status of the cancer to all members of the Interprofessional care team 
    • Assist in determining the most effective treatment plan
    • Evaluate the treatment plan
    • Predict prognosis
    • Compare like groups for statistical purposes.
  • Ability of malignant tumor cells to invade and metastasize is major difference between benign and malignant neoplasms

 

Classification of cancer

  • Tumors can be classified by
    • Anatomic site
    • Histology 
      • Grading severity
    • Extent of disease
      • Staging
  • Classification systems provide a standardized way to 
    • Communicate with health care team
    • Prepare and evaluate treatment plan
    • Determine prognosis
    • Compare groups statistically
  • Anatomic site classification
    • Identified by tissue of origin
    • Carcinomas originate from 
      • Embryonal ectoderm (skin, glands) 
      • Endoderm (mucous membrane of respiratory tract, GI and GU tracts)
    • Sarcomas originate from 
      • Embryonal mesoderm (connective tissue, muscle, bone, and fat)
    • Lymphomas and leukemias originate from 
      • Hematopoietic system
  • Four grades of abnormal cells
    • Grade I
      • Tumor limited to tissue of origin; localized tumor growth
    • Grade II
      • Limited local spread
    • Grade III
      • Extensive local and regional spread
    • Grade IV
      • Cells are immature and primitive and undifferentiated
      • Cell of origin is difficult to determine
      • Metastasis
  • TNM classification system
    • Anatomic extent of disease is based on 3 parameters:
      • Tumor size and invasiveness (T)
      • Spread to lymph nodes (N)
      • Metastasis (M)
  • Staging
    • Performed initially and at several evaluation points
      • Clinical staging
        • Done at completion of diagnostic workup to guide effective treatment selection
          • Bone and liver scans, ultrasonography, CT, MRI, PET scans
      • Surgical staging
        • Determined by surgical excision, exploration, and/or lymph node sampling
        • Exploratory surgical staging is being used less frequently

Diagnosis of cancer

  • Diagnostic plan includes
    • Comprehensive Health History 
    • Identification of risk factors
    • Physical examination
    • Specific diagnostic studies
  • Indicated diagnostic studies depend on site of cancer
    • Lab works
    • Cytology studies
    • Chest x-ray
    • Endoscopic examinations
    • Radiographic studies
    • Radioisotope scans
    • PET scan
    • Tumor markers
    • Genetic markers
    • Bone marrow examination
    • Biopsy
  • Patient may experience fear and anxiety
    • Actively listen to patient’s concerns
    • Manage your own discomfort
    • Give clear explanations; repeat if necessary
    • Give written information for reinforcement
    • Refer to oncology team when possible
  • Manage your own discomfort
    • Avoid 
      • Communication patterns that may hinder exploration of feelings
      • Use of overly technical language
    • Encourage patients to share the meaning of their experience
    • Listening is an important skill at this time
  • Prevention is key
    • The war on cancer will not be won with drugs or radiation therapy
    • A stronger emphasis on prevention is needed
    • Nurses have an essential role
  • Education is essential
    • Goals of public education
      • Motivate people to recognize and modify behaviors that may negatively affect health
      • Encourage awareness of and participation in health-promoting behaviors
    • What you would tell the patient about cancer
      • Cell proliferation, or growth, originates in the stem cell and begins when the stem cell enters the cell cycle. Normally, cells differentiate and become mature, functioning cells of a certain kind of tissue.  There is an equilibrium between cell proliferation and cell degeneration.  In cancer, cells respond differently than normal cells to the intracellular signals that regulate the state of dynamic equilibrium. Cells respond differently and divide indiscriminately and haphazardly.  When they produce more than 2 cells at the time of mitosis, there is continuous growth of a tumor mass, called the pyramid effect. 
      • Cell differentiation is normally a stable, orderly process that progresses from a state of immaturity to a state of maturity. Cancer results in malfunction in that process. 
      • Cancer involves the malfunction of genes that control differentiation and proliferation.
    • Is cancer genetically linked?
      • A common misbelief is that the development of cancer is a rapid, haphazard event. However, cancer is usually an orderly process comprising several stages and occurring over a period of time. 
      • The first stage, initiation, is a mutation in the cell’s genetic structure. 
      • Gene mutations can occur in two different ways: inherited from a parent (passed from one generation to the next) or acquired during a person’s lifetime. 
      • About 5% to 10% of all cancers or the predisposition to the cancers are inherited from one’s parents. These genetic alterations lead to a very high risk of developing a specific type of cancer. 
      • However, most cancers do not result from inherited genes but are acquired from damage to genes occurring during one’s lifetime. An acquired mutation is passed on to all cells that develop from that single cell. 
      • The damaged cell may die or repair itself. However, if cell death or repair does not occur before cell division, the cell will replicate into daughter cells, each with the same genetic alteration.
    • Role of UV light
    • UV radiation is considered a carcinogen.
    • Carcinogens may be chemical, radiation, or viral.
    • Ultraviolet (UV) radiation has long been associated with melanoma and squamous and basal cell carcinoma of the skin. 
    • Skin cancer is the most common type of cancer among whites in the United States. Of great concern is the increase in the incidence of melanoma. Although the cause of melanoma is probably multifactorial, UV radiation secondary to sunlight exposure is linked to the development of melanoma.
  • Prevention and detection of cancer
    • Cancer is a group of diseases characterized by uncontrolled and unregulated growth of cells. 
    • Cancer affects people of all ages and affects men more than women.
    • It is the second most common cause of death in the United States after heart disease.
    • More people are surviving cancer.
    • Lifestyle habits to reduce risks
      • Practice recommended cancer screenings
        • Learn and practice the recommended American Cancer Society cancer screening guidelines for breast, colon, cervical, and prostate cancer.
      • Practice self-examination
      • Know seven warning signs of cancer
      • Seek medical care if cancer is suspected
      • Avoid or reduce exposure to known or suspected carcinogens
        • Cigarette smoke, excessive sun exposure
      • Eat a balanced diet
        • Eat a balanced diet that includes vegetables and fresh fruits, whole grains, and adequate amounts of fiber. 
        • Reduce dietary fat and preservatives, including smoked and salt-cured meats containing high nitrite concentrations.
      • Limit alcohol intake
      • Exercise regularly
        • Participate in regular exercise (i.e., 30 minutes or more of moderate physical activity five times weekly).
      • Maintain a healthy weight
      • Get adequate rest
        • Obtain adequate, consistent periods of rest (at least 6 to 8 hours per night).
      • Eliminate, reduce, or cope with stress
        • Enhance the ability to effectively cope with stressors.
      • Have a regular health examination
        • Be familiar with your family history
        • Know your risk factors

 

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