Med-Surg: Chapter 13: Overview of Cancer Care Flashcards
Cancer
constellation of diseases involving a malignant (unregulated) transformation of cells within a specific body system
- all cancers characterized by uncontrolled growth of malignant cells that compromises the integrity and function of normal, healthy cells
- second leading cause of death
Carcinogen
cancer trigger
- internal or external exposures that predispose individuals to DNA destruction, resulting in cellular mutation that may lead to malignant transformation of cells
- exposure varies across nations for different reasons, leading to different cancer disease patterns
- most common risk factor for cancer
ex: ionizing radiation, benzene, HPV, sun exposure, and tobacco - carcinogen alone is unlikely to trigger cancer
Most Common Risk Factor for Cancer
exposure to a carcinogen
Examples of Carcinogens
- ionizing radiation
- benzene
- HPV
- sun exposure
- tobacco
Carcinogenesis
the initiation and promotion of cancer
- involves a series of other molecular changes that occur after exposure to carcinogens
- > for this reason, not all individuals with known risk factors or known exposure to a carcinogen develop the disease
Believed to Influence the Development of Cancer
- environmental, hormonal, and lifestyle factors
- infectious diseases
- medications
- immune status
- nutritional factors
Nonmodifiable Risk Factors for Cancer
factors that the individual cannot change
- age
- genetic predisposition
- advanced age increases the risk; r/t greater exposure to carcinogens over time and changes in immune function
Modifiable Risk factors for Cancer
- lifestyle; a sedentary and poor diet and/or smoking
- cancer associations with specific diseases, such as the relationship between colon cancer and inflammatory bowel disease or hepatic cancer resulting from hepatitis C infection, are modifiable but only as much as the management of the triggering disease
Pathophysiology of Carcinogenesis
cancer initiation begins with carcinogen exposure, which triggers single- or multiple-gene mutations
-an individual likely experiences multiple carcinogen exposures and genetic mutations over time; however, the immune system protects the individual by recognizing the mutation and initiating cell death
>in carcinogenesis, the mutated cells are not detected by the immune system an are therefore able to proliferate and progress into cancer
Cancer is Characterized by 2 hallmark characteristics
- Uncontrolled cell growth
- Altered cell differentiation
Uncontrolled Cell Growth
> Normal cells grow in a structured pattern, and stimulation for cell growth is tightly controlled so that the number of cells produced by the body is roughly equivalent to the number of cells lost through cell death or shedding
-Cancer cell growth and proliferation are unregulated by typical mechanisms
> Normal Cells are regulated by contact inhibition and stop growing and reproducing when they come into contact with other cells
-Cancer Cells lack contact inhibition
> A regular cell cycle that ends with programmed cell death (apoptosis), is common with normal cells
-Cancer cells do not undergo apoptosis
> Normal cells need to anchor to either neighboring cells or basement cells so that they can plug into a nutrient-rich extracellular matrix to remain viable
-Cancer cells do not have this type of anchorage dependence and can grow and flourish in atypical patterns and environments
> This uncontrolled growth can result in dysplasia , or deranged cell growth, in which cells vary in size, shape, and organization
Neoplasia (uncontrolled cell proliferation); describes a new cell-growth pattern that is characteristic of cancer
What are Cancer Cells
malignant neoplasms that grow uncontrollably and invade surrounding tissues and vessels
-have the capacity to destroy normal tissue, steal nutrition, create their own blood vessels, and survive even under anoxic or acidotic conditions
Altered Cell Differentiation
> healthy, fully developed cells are well differentiated and have specific structural and functional characteristics
- A malignant cell derives from a parent cell, such as a breast tissue cell, but no longer performs the expected functions of the parent cell, and the structure may be different as well
- when a cell loses expected structure and function, it is called anaplasia
- as cancer proliferation progresses, the cancer cell loses similarity to the parent cell
> there is a range in pathological presentation: cancer cells may be well differentiated and look similar to the parent cell
- may be undifferentiated and look nothing like the parent cell
- or somewhat in between
> Poorly differentiated cells are more difficult to treat
-these cancers often associated with more refractory and aggressive tumors, even if from the same tissue origin
Anaplasia
when a cell loses expected structure and function
-as cancer proliferation progresses, the cancer cell loses similarity to the parent cell
Tumor Grading
mechanism to classify or describe tumors
- used to plan treatment
- the extent of differentiation is an important element in grading malignant neoplasms
Metastasis
spreading of tumors
- cancer cells replicate and expand locally into masses of cells known as malignant tumors
- cancer cells spread by cell-to-cell transfer, through the lymphatic system, or through the blood (hematogenous)
- metastasize in a predictable pattern
Metastasis: Spread by cell-to-cell transfer
characterized by direct invasion into adjacent cells
Metastasis: Spreads by Lymphatic System
lymphatic spread occurs when the tumor cells migrate into the lymphatic system using lymph channels that serve the organ where the cancer originated
-once in a lymph node, the cancer cell may be destroyed, grow into a mass, remain dormant, or spread to more distant lymph nodes and potentially into the vasculature
Metastasis: Hematological Spread by cancer cells
spread through the blood system
-occurs when the cancer cell migrates into the venous system that drains the organ where the cancer originated
The Stages of Cancer Metastasis
- Cancer cells in the primary site
- Cancer cells invade surrounding tissues and blood vessels/ lymph vessels
- Cancer cells are transported by the circulatory system/ lymphatic system to distant sites
- Cancer cells reinvade and grow at a new location
Examples how Cancer Cells Metastasize in Predictable patterns
> Prostate cancer is notable for a tendency to spready by cell-to-cell transfer, so advanced disease is most likely to present with metastasis to nearby tissues, such as the rectum, pelvic floor, lower spine, or hip
> Colorectal cancer commonly metastasizes hematogenously, and b/c the blood supply in closest proximity to the colon is the portal circulation, the liver is the common site for metastasis
> when a tumor metastasizes, it often remains molecularly similar to the tumor of origin
- prostate cancer that has metastasized to the rectum has the same cellular and molecular qualities as prostate cancer; the prostate cancer cell has simply relocated to the rectum to create a prostate cancer tumor in the rectum; in other words, a rectal tumor originating from cancer of the rectum is different from a rectal tumor originating from cancer of the prostate
- the tumor in the prostate is the Primary tumor, and the tumor in the rectum is the Secondary tumor (or metastatic tumor)
Cancers are Divided into Two main Categories
- Solid-tumor malignancies
- Hematological malignancies
Solid-Tumor Malignancies
arise from specific body organs and grow into masses that invade and erode normal body tissue as they expand in size
-ex: lung cancer
Hematological Malignancies
arise form cells of the hematopoietic cell line or from secondary immune organs such as lymph nodes or spleen
-the hematopoietic stem cell gives rise to all myeloid and lymphoid cells in the body, which later develop into cells of the blood system and immune system; a hematological malignancy can therefore affect any of the blood cells in the hematopoietic cell line, including RBCs, WBCs, and Platelets
>Three major Subcategories of Hematological Malignancies
-Leukemia: cancers involving blood cells
-Lymphoma: cancers involving the lymphatic system
-Multiple myeloma: cancers involving plasma cells and immunoglobulins