Unit I - Oncology Flashcards
neoplasia
new growth - tumor
benign tumor
have a capsule and push surrounding tissue aside but do not invade surrounding tissue
malignant tumor
- Ill defined edges, no capsule, locally invasive by direct extension
- usually larger than benign tumors because of autonomous growth
- metastasize, which means that cells break off from the parent tumor and move to a distant organ
mechanisms of metastasis
hematogenous spread (blood vascular system) lymphogenous spread (lymphatic system)
neuroblastomas
usually in peripheral nervous system and may drive from nerve tissue in adrenal medulla
common in young children
glioblastomas
glial cells, CNS tumors
grade I - mildly agressive
grade IV - very aggressive (glioblastoma multiforme)
factors contributing to the metastatic quality of malignant cells
- lack of adhesiveness (cells do not adhere to each other)
- lack of contact inhibition (cells behavior is not governed by surrounding cells)
- increased motility (cells are active)
- lack of contact guidance (cell growth is independent of surrounding cells)
morphologic qualities of malignant cells - dysplasia
cells have an abnormal appearance, such as irregular shape or nucleus
morphologic qualities of malignant cells - early form of dysplasia
metaplasia - benign and potentially reversible change in which an adult cell changes from one type into another
morphologic qualities of malignant cells - pleomorphism
cells have different sizes and shapes
morphologic qualities of malignant cells - anaplasia
cells resemble embryonic cells, lack differentiation, and have a high reproductive rate
cancer staging
process of describing the extent of the disease or the spread of the cancer from the site of origin
- essential in determining the choice of therapy and assessing prognosis
stage of cancer is determined by
primary tumor’s size and location in the body, and whether or not it has spread to other areas of the body
summary of cancer staging
- in situ - cancer cells are present only in the layer of cells they developed in and have not spread to other parts of the body
- invasion of local tissue - cancer cells have spread beyond original layer of tissue
- invasion of regional lymph nodes
- distant metastasis - cancer cells have spread to other organs in the body
TNM staging system
assesses tumors in 3 ways:
- extent of primary tumor (T)
- absence or presence of regional lymph node involvement (N)
- absence or presence of distance metastasis (M)
once the T,N,M are determined, a “stage” of I, II, II, or IV is assigned
staging by cell type of origin
- low grade (localized) - cell types resemble normal, fully differentiated cells
- high grade (metastatic) - cell types are poorly differentiated and tend to metastasize early to distant organ sites
endogenous cancers
show a familial or hereditary pattern
exogenous cancers
from an external cause - environmental or behavioral factors that cause malignant mutations in cells
pathogenesis
tumors form when there is an increased mitotic rate, DNA mutation, and hyperplasia
oncogenes
porto-oncogenes: normal genes that can become oncogenes due to mutation
anti-oncogenes: suppressors, block cancer cells from forming (BRCA)
cancer cells can spread to local tissue by
direct extension
metastasis
cells break off from each other and travel to distant organ sites
seeding
metastatic tumor cells depositing in highly vascular organs
s/s of malignant neoplasm
pathologic fractures, pressure on tissue causing obstruction, erosion, bleeding, infection, anemia, hormones/metabloic disturbances, cachexia, palpable enlargement, migatory thrombophlebitis, pananeoplastic syndrome
