Cancer Flashcards
most common causes of death in US
1st: heart disease
2nd: cancer
most common sites of cancer in men
- prostate
- lung and bronchus
- colon and rectum
most common sites of cancer in women
- breast
- lung and bronchus
- colon and rectum
What is cancer?
- A collection of diseases which share
common characteristics: - Uncontrolled cell proliferation
- Insensitivity to anti-growth signals
- Prevention of cells to self-destruct through apoptosis
- Limitless replicative potential
- Sustained angiogenesis
- Tissue invasion and metastasis
Cancer develops when…
a normal cell becomes abnormal
cancer often involved the malfunction of what?
- genes that control cell growth, cell division, or
cell death - Activation of proto-oncogene
- down-regulation of tumor-suppressor gene
What do Onco-genes do?
essentially put the “brakes” on apoptosis and cause normal cells to reproduce relatively unchecked
What does tumor suppressor gene provide?
- inhibitory signals that lead to the cessation of cell division and DNA transcription
- Mutations in these genes are considered a loss of function –> genomic instability and the
potential for cancer initiation
Sequence of events necessary for successful metastatic spread:
- Detachment and escape from primary tumor site
- Invasion of surrounding tissues and penetration into circulatory or lymphatic channels and survival without detection
- Invasion and colonization at a distant site.
- Once invasion of a new site occurs, persistent survival in this environment, and subsequent angiogenesis for further proliferation, require additional mechanisms and capabilities
Cancer causes - risk factors?
- Genetic factors
- physical carcinogens
- chemical carcinogens
- biological carcinogens
Genetic factors
up to 10% of all cancers can be caused by inherited genetic changes
physical carcinogens
UV and ionizing radiation
chemical carcinogens
asbestos, tobacco smoke, arsenic, aflatoxin
biological carcinogens
- Infections from certain viruses, bacteria, and parasites
- Human papilloma virus (HPV), Hepatitis B virus (HBV), Hepatitis C virus (HCV), and Helicobacter
pylori (H. pylori)
Categories of drugs used to treat cancer
- Chemotherapy
- Immunotherapy
- Target therapy
- Anti-hormonals
- Often used in combinations and come in the form of liquid or pills
- Each has a diverse target with a distinct mechanism of action (MOA)
- Many have a narrow therapeutic index (TI)
Main goal of chemotherapy
- Eliminate the cancer cells without affecting normal tissues
- Cytotoxic drugs affect both normal and cancerous cells
- Aim for a favorable therapeutic index
cost of chemotherapy
- one of the most expensive medical conditions
- patents and survivors of cancer are more likely to have financial toxicity than those without cancer
- CAR-T cell therapy is $475,000 for one treatment
What can limit the dose of chemotherapy
- Toxicity
- Poor selectivity of drugs for cancer cells versus normal cells means both healthy and cancerous cells are affected
Which tissues are often the cause of dose-limited toxicities
- Bone marrow
- GI tract (primarily the mucosal lining)
- Skin
- Germinal cells (sperm & ova)
- Hair follicles
(tissues with high growth rates)
Implications for physical therapy
- A clear understanding of the complex and ever-changing use of chemotherapeutics and supportive medications is one of the most challenging parts of working with people with cancer
- Important to understand the clinical aims, MOA, and adverse effects of antineoplastic agents to provide optimal care
- A comprehensive rehabilitation program can improve a person’s ability to tolerate
a more aggressive treatment regimen
Common Toxicities - Myelosupression
- inhibition of bone marrow cells resulting in fewer red blood cells, white cells, and/or platelets
- Neutropenia, Thrombocytopenia, Anemia
Neutropenia
- Low white bloods cell count
- Increased risk of infection
Thrombocytopenia
- Low platelet count
- Bruising, nosebleeds, and/or bleeding gums
- Malaise, fatigue, and weakness
Anemia
- Low red blood cell count
- Vague symptoms: tiredness, weakness, SOB, decreased activity tolerance
Common toxicities: GI system
- Diarrhea
- Nausea, vomiting
- Stomatitis –> Inflammation and ulceration of the oral mucosa
- Mucositis –> Painful inflammation or ulceration of the mucus membranes anywhere in the GI tract
Common Toxicities: Integumentary
Hand Foot Syndrome
What is hand foot syndrome
- Pain, redness, peeling of the skin on palms and/or soles of the feet
Treatment for hand-foot syndrome
- Adjusting does of chemotherapy or changing the drug
- May reduce efficacy of cancer treatment
Integumentary - Management
- Corticosteroid creams
- Skin moisturizers
- Pain relievers: oral or topical
- Avoid activities that cause friction on palms
or soles
Common Toxicities: Nervous System
- Chemotherapy-Induced Peripheral Neuropathy (CIPN)
- Common, potentially debilitating and dose-limiting side effect of cancer treatment that
may occur when chemotherapeutic agents damage the peripheral nerves - Pathophysiology is poorly understood
Symptoms of chemotherapy-induced peripheral neuropathy
- Begin in the hands and feet and move proximally
- Pain, burning, tingling, numbness, electric shock, pins and needles, temperature sensitivity
- Affect ADLs and QoL
- Can persist months to years after completion of chemotherapy
Chemotherapy- Induced Peripheral Neuropathy results in ….
- Deficits in sensory, motor and/or autonomic functions
- Sensory symptoms develop first – “glove and stocking” distribution –> Numbness, tingling, altered touch sensation, impaired vibration, paresthesias, dysesthesias induced by touch and warm or cool temperatures, painful sensations including spontaneous burning, shooting or electric-like pain
- Motor symptoms – less frequent than sensory –> Distal weakness, gait and balance disturbances, impaired movements