Oncology and Hematologic Cancers Study Guide

Overview and Key Terminology

  • Benign Neoplasms

    • These consist of well-differentiated cells that resemble the cells in the tissue of origin.

    • They are usually clustered together in a single mass.

    • They normally do not cause cell death, although their size may interfere with the function of surrounding organs.

    • They are slow-growing and remain contained within their origin site.

    • They are usually encapsulated and grow by expansion without invading surrounding tissues.

  • Malignant Neoplasms

    • These consist of poorly differentiated or undifferentiated cells, often exhibiting anaplasia and atypical structures that bear little resemblance to the tissue of origin.

    • They possess the ability to break loose from the primary site and enter the circulatory or lymphatic system.

    • They form secondary malignant tumors at other sites in the body.

    • Their growth is uncontrolled and uncontained.

    • Examples of growth mechanisms include infiltration, invasion, and penetration of surrounding tissues.

    • The rate of growth is variable and depends on the level of differentiation; generally, the more undifferentiated the cells, the more rapid the growth rate.

  • Metastasis

    • Defined as the detachment of cells from the original (primary) tumor and their spread to other sites via blood and lymph channels.

    • This results in the formation of a secondary tumor in a location other than the primary site.

  • Specific Cancer Classifications

    • Solid Tumor: A tumor confined to a specific tissue or organ (e.g., lung cancer).

    • Hematologic Cancers: Cancers that involve the blood (e.g., leukemia).

    • Squamous Cell Carcinoma: Cancer arising from squamous cells.

    • Adenocarcinoma: Cancer originating in glandular tissue.

    • Adenoma: A benign tumor of glandular epithelial tissue.

Common Sites of Cancer Metastasis

Based on findings from the National Cancer Institute, specific primary cancers tend to metastasize to consistent secondary sites:

  • Breast: Lung, liver, and bones.

  • Colon: Liver, peritoneum, and lung.

  • Kidney: Lung, liver, and bones.

  • Lung: Adrenal gland, liver, and lung.

  • Melanoma: Skin, muscle, and liver.

  • Ovary: Liver, peritoneum, and lung.

  • Pancreas: Liver, lung, and peritoneum.

  • Prostrate: Lung, liver, and bones. (Note: Transcript spelling preserved).

  • Rectum: Liver, peritoneum, and adrenal gland.

  • Stomach: Liver, peritoneum, and lung.

  • Thyroid: Lung, liver, and bones.

  • Uterus: Liver, peritoneum, and lung.

Risk Factors and Carcinogenesis

  • Genetic Factors

    • Cancer is driven by genetic damage, mutations, and translocations.

    • It involves the suppression of suppressor genes.

    • It results from damage to pathways that control normal DNA function and repair.

    • Oncogenes: Genes that exhibit over-activity, promoting cancer cell growth.

    • Tumor Suppressor Genes: Genes that exhibit under-activity, failing to stop uncontrolled cell division.

  • Carcinogenesis

    • The process by which carcinogenic agents transform a normal cell into a cancer cell.

    • These chemical, physical, or biologic agents produce irreversible changes to the DNA of normal cells.

  • Additional Risk Factors

    • Heredity: An inherited predisposition that increases the risk for developing certain types of cancers.

    • Hormones: Certain tumors are hormone-responsive and increase in size or growth rate in the presence of specific hormones.

    • Immunologic Mechanisms: A normal immune system protects against cancer development; states of suppressed or altered immune function (e.g., HIV/AIDS, immunosuppression, or advanced age) increase risk.

    • Chemical Carcinogens: Agents that cause cancer, such as smoking, chewing tobacco, other tobacco products, dietary factors, and ETOH. Effects are dose-dependent (larger dose/exposure equals greater risk).

    • Radiation: Includes ionizing radiation (industrial exposures, high-dose x-ray) and ultraviolet radiation.

    • Oncogenic Viruses: Viruses that enter a host and use host DNA to replicate, such as HPV and Hepatitis B.

Clinical Manifestations and Symptoms

  • Tissue Integrity: Ulceration, necrosis, bleeding, abnormal healing, and effusions.

  • Anorexia and Cachexia

    • Anorexia: Reduced food intake and altered taste.

    • Cachexia: Physical wasting involving loss of weight in both fat and skeletal muscle. This is not responsive to nutritional support and involves altered metabolism.

  • Fatigue and Sleep Disorders: Descriptions include tiredness, weakness, and lack of energy. This fatigue is often unrelieved by rest and may be associated with the treatment process.

  • Anemia: Caused by blood loss, hemolysis, impaired RBC production, or treatment effects. It may be linked to nutritional deficits and bone marrow failure.

  • Pain: A common symptom associated with cancer and its progression.

Cancer Treatment Approaches

  • Surgery

    • Used for diagnosis, staging, tumor removal, and palliation (relief of symptoms).

  • Radiation

    • Utilizes high-energy particles or waves to destroy or damage cancer cells.

    • It negatively affects normal tissue that rapidly proliferates; tissues within the treatment field are most severely impacted.

    • Adverse effects include fatigue and bone marrow suppression.

  • Chemotherapy

    • Employs lethal action targeting processes that prevent cell growth and replication.

    • Common side effects include the death of rapidly dividing normal cells (e.g., skin, hair, and GI tract).

  • Hormone Therapy

    • Alters hormone levels to treat hormone-sensitive tumors.

  • Biotherapy (Immunotherapy)

    • Alters the natural immune response to improve the control of cancer growth.

    • Uses biologic response modifiers such as cytokines and interferons.

Focus on Hematologic Cancers

  • Leukemia: Starts in the bone marrow and involves the over-proliferation of leukocytes (WBCs).

  • Lymphoma: Starts in the lymphatic system and involves the over-proliferation of lymphocytes.

  • Multiple Myeloma: Starts in the plasma cells, which are cells required for antibody production.

  • Key Considerations for Hematologic Cancers:

    1. Impact on bone marrow function.

    2. Risk for immune system dysfunction.

    3. Potential requirement for bone marrow transplant.

Detailed Profile: Leukemia

  • Pathophysiology

    • Cancer of the blood cells, usually leukocytes.

    • Immature Blast Stage: Cells cannot mature and they divide rapidly.

    • These cells drain the resources within the bone marrow.

  • Classification and Types

    • Acute Leukemia:

      • Acute Myelogenous Leukemia (AML): Associated with infection and bleeding.

      • Acute Lymphocytic Leukemia (ALL): Primarily affects children.

    • Chronic Leukemia:

      • Chronic Myelogenous Leukemia (CML).

      • Chronic Lymphocytic Leukemia (CLL).

  • Signs and Symptoms

    • Low RBC count, low Hgb (Hemoglobin), and low Hct (Hematocrit).

    • Low Platelets and resultant bruising.

    • Weakness and bone pain.

    • Intermittent fever with no other specific findings.

  • Complications

    • Neutropenia, Anemia, Bleeding, and Fungal infections.

  • Treatment

    • Chemotherapy and Radiation.

    • Targeted Immune Therapy.

    • Bone Marrow Transplant.

    • Supportive care.

Detailed Profile: Lymphoma

  • Classification

    • Hodgkin Lymphoma:

      • Linked to the Epstein Barr Virus, genetic factors, and environmental factors.

      • Known as one of the most curable forms of cancer.

    • Non-Hodgkin Lymphoma (NHL):

      • Linked to chromosomal translocations, infections, environmental factors, AIDS, chemotherapy, and radiation.

      • The more common type of lymphoma.

      • Risk increases with advanced age.

  • Clinical Manifestations

    • Swollen lymph nodes in the axilla, neck, and groin.

    • Fever and night sweats.

    • Unexplained weight loss and fatigue.

  • Treatment

    • Chemotherapy and Radiation.

    • Immunotherapy (specifically for NHL).

Detailed Profile: Multiple Myeloma

  • Pathophysiology

    • Cancer of the plasma cells.

    • Characterized by bone marrow and skeleton tumors.

    • Malignant plasma cells penetrate the bone marrow (BM) to form tumors.

  • Signs and Symptoms

    • Bone pain, specifically in the spine and chest.

    • Pain or numbness in the legs.

    • Fatigue, weight loss, and decreased appetite.

  • Complications

    • Infection.

    • Brittle bones.

    • Anemia of chronic disease.

    • Kidney failure.

  • Treatment

    • Treatment depends on severity.

    • Chemotherapy, Bisphosphonates, and Radiation.

    • This condition is rarely cured, but treatment may provide pain relief.

Hematopoietic and Lymphoid Tissues

  • WBC Formation

    • White blood cells (WBCs) are formed from hematopoietic stem cells.

    • These differentiate into committed progenitor cells, which develop into:

      1. Myelocytic lineages.

      2. Lymphocytic lineages.

    • These lineages are essential for forming different WBC types.

  • Biological Constraints

    • The lifespan of a WBC is relatively short, necessitating constant renewal to maintain normal blood levels.

    • Any condition that decreases the availability of stem cells or hematopoietic growth factors causes a decrease in WBC count.

Neutropenia (Agranulocytosis)

  • Definition and Role

    • Neutrophils are the most abundant WBC.

    • They are essential for infection management.

    • Low levels (neutropenia) lead to an increased risk for infection and increased severity of infections.

  • Management

    • Neutropenic Precautions: Procedures implemented to protect the patient from infection.

  • Causes

    • Congenital: Present from birth.

    • Acquired: Developed over time.

    • Autoimmune: The body attacks its own neutrophils.

    • Infection: Certain infections deplete neutrophils.

    • Cancer Chemotherapeutic Drugs: A major cause of acquired neutropenia.