Neoplasm
A new abnormal growth or tumor
Oncology
Study of neoplasms (tumors) or cancer
Tumor parenchyma
The clonal neoplastic cancer cells of a tumor
Tumor stroma
Supportive tissue including connective tissue, blood vessels, and immune cells. Growth and evolution of the tumor dependent on the stroma.
Benign tumor
Localized, encapsulated, slow growing tumor that does not metastasize. Usually differentiated cells that reproduce at a higher rate than normal and can cause tissue damage (result of compression of adjacent structures).
Malignant tumor
Invasive, rapidly, growing tumor capable of metastasis and tissue destruction. Undifferentiated (Look nothing like normal healthy cells) and nonfunctional.
Key difference benign vs malignant
Benign stays localized while malignant invades and spreads
Typical benign naming rule
Cell type plus suffix -oma
Carcinoma
Malignant tumor arising from epithelial tissue (Most common)
Sarcoma
Malignant tumor arising from mesenchymal/connective tissue
Adenocarcinoma
Malignant epithelial tumor forming glandular structures
Teratoma
Tumor containing tissues from multiple germ layers: Ectoderm (nervous tissue and epithelial tissue), Mesoderm (muscle, connective tissue), and endoderm (digestive system and internal organs) (More rare)
Malignant tumor characteristics
Rapid growth, abnormal mitosis, lack of differentiation, invasion, metastasis, angiogenesis
Angiogenesis
Formation of new blood vessels to supply tumor growth
Loss of contact inhibition
Cancer cells continue growing despite touching neighboring cells
Common cancer warning signs
Unusual bleeding, persistent lump, chronic cough, unexplained weight loss, change in bowel or bladder habits, nonhealing sore, change in mole
Where cancer can arise: Epithelia
High occurrence (80% of cancer deaths); Carcinoma. Highest risk of exposure and high replacement rate (highly mitotic)
Where cancer can arise: Connective
Sarcomas (1% of tumors in clinics). Bone, cartilage, fat, muscle, blood vessels, or other connective/supportive tissues
Where cancer can arise: Blood forming (hematopoietic) tissues
Leukemia (starts in marrow and produces abnormal blood cells that enter the blood) and lymphoma (begin in cells of the immune system) (17% of cancer related deaths)
Where cancer can arise: Central and Peripheral Nervous System
Spinal cord and outlying nervous tissues. Neuroectodermal tumors (2.5% of cancer related deaths)
Local tumor effects
Pain, obstruction, tissue necrosis, bleeding, infection
Tumor obstruction effect
Compression of ducts vessels or airway impairing organ function
Systemic cancer effect cachexia
Severe weight loss and muscle wasting due to cancer metabolism
Systemic cancer anemia
Blood loss or nutritional deficiency reduces hemoglobin
Systemic cancer Severe fatigue
Caused by inflammatory changes, cachexia, anemia, stress of treatment schedule, and psychological factors
Effusion
Fluid buildup in body cavities due to inflammation
Systemic cancer Infections
Occur frequently as resistance declines
Systemic cancer Bleeding
Tumor cells may erode the blood vessels
Paraneoplastic syndrome
Systemic hormonal or neurologic effects caused by tumor secretions
Diagnostic tests
Routine screening, self-examination, blood tests, tumor markers, and genomic tumor assessment
Cancer screening and self-examination
Purpose is early detection and monitoring recurrence
Blood tests
Measure blood cell levels during treatment. May detect tumor markers.
Tumor markers
Substances, enzymes, antigens, or hormones produced by cancer cells detectable in blood
Genomic tumor assessment
Testing tumor DNA mutations to guide treatment
Imaging for cancer diagnosis
Xray, CT, MRI, ultrasound used to visualize tumor location
Biopsy
Removal of tissue sample for histologic confirmation of cancer
Histology vs cytology
Histology examines tissue structure while cytology examines individual cells
Most reliable cancer confirmation
Biopsy with histologic examination
How do cells invade and spread?
1. Altered cell adhesion (cadherins) 2. Change in interaction with stroma (loses anchors/integrins) 3. Altered synthesis of enzymes that break down basement membrane and stroma (Metallopeptidases); factors produced that help cells spread (scatter factor)
Invasion ability
Cancer cells break through basement membrane and then spread into surrounding tissue and lymphatic/vasculature channels. Malignant cells.
Metastasis
Spread of cancer cells to distant sites through lymph blood or body cavities
Primary tumor
Original site where cancer begins
Secondary tumor
Metastatic growth at distant location
Common metastasis route lymphatic
Spread through lymph nodes common for carcinomas
Common metastasis route blood
Spread through veins to lung liver brain or bone
Coelomic spread
Cancer spread through body cavity fluid such as ovarian cancer
Role of cadherins in cancer
Reduced adhesion allows tumor cells to detach and migrate
Role of integrins in cancer
Altered interaction with stroma allows invasion and movement
Matrix metalloproteinases
Enzymes that break down basement membrane to allow tumor spread
Carcinogenesis
Process of normal cells transforming into cancer cells
Initiation stage
First irreversible DNA mutation caused by carcinogen
Promotion stage
Hormones and environmental chemicals that cause further DNA changes that increase proliferation and reduce differentiation
Proto-oncogene
Normal gene regulating growth that can mutate into cancer promoting oncogene
Oncogene
Mutated gene increasing cell growth and division. Cell growth and survival increase; accelerates cell division; gas pedal. Gain of function mutation- increase activity or expression level of a gene product
Tumor suppressor gene
Gene that normally inhibits cell division or promotes apoptosis; brakes that protect cells from carcinogenesis. Loss of function mutation- gene product has lost partial or total activity or expression.
Loss of tumor suppressor function
Removes cell growth control and promotes cancer
Cancer risk factors genetic
Inherited mutations affecting growth regulation
Cancer risk factors viral
Oncoviruses that alter host DNA such as HPV or hepatitis B
Cancer risk factors radiation
UV rays, x rays, gamma radiation, cumulative exposure
Cancer risk factors chemicals
Asbestos, solvents, heavy metals, formaldehyde
Cancer risk factors lifestyle
Smoking, alcohol, diet, obesity, inactivity
Cancer prevention avoid tobacco
Eliminates major carcinogen exposure
Cancer prevention diet
High fiber fruits vegetables antioxidants reduce DNA damage
Cancer prevention vaccination
HPV and hepatitis B vaccines reduce cancer risk
Host defense tumor suppressor genes
Normal mechanisms that block carcinogenesis
Host defense immune system
Cell mediated immunity recognizes and destroys tumor cells
Cancer staging
Purpose is determine prognosis and treatment planning
In situ cancer
Cells remain in original layer and have not invaded
Invasive cancer
Cancer has penetrated basement membrane and spread locally
TNM staging
T describes tumor size N lymph node involvement M metastasis
Stage IV cancer
Most advanced cancer with distant metastasis
Cancer treatment options
Surgery, radiation, chemotherapy, immunotherapy, or combination therapy
Surgery for cancer
Removal of tumor and surrounding tissue
Radiation therapy
Uses ionizing radiation to damage DNA of rapidly dividing cancer cells
Radiation side effects
Bone marrow suppression, infection, fatigue, hair loss, infertility
Chemotherapy
Antineoplastic drugs that interfere with DNA replication or protein synthesis
Chemotherapy side effects
Bone marrow suppression, nausea, epithelial damage, hair loss, organ toxicity
Hormone blocking therapy
Drugs that block growth signals to hormone sensitive tumors
Biological response modifiers (BRMs)
Drugs that enhance immune response against cancer
Angiogenesis inhibitors
Drugs that prevent tumor blood vessel formation
Cancer nutrition issue
Many patients develop malnutrition due to treatment effects
Cancer metabolic demand
Tumors often have high glucose requirements
Remission
Period with no clinical signs of cancer
Five year survival
Common benchmark used to define cancer free status