Class 8. Cancer Flashcards
- What are the tests performed as part of a CBC & diff
- Neutropenia is a common occurrence in childhood cancer – either from the disease itself or from the treatment. What is neutropenia and what is the ANC (how is it calculated)?
- What are common side effects of cancer treatment and how are they managed? Pay specific attention to myelosuppression.
- What is chemotherapy and how does it work? (You do not need to know the specific medications listed on pp. 995-997 & 999.)
Leukemia
Brain tumours
Rhabdomyosarcoma:
Rhabdomyosarcoma is a type of sarcoma. Sarcoma is cancer of soft tissue (such as muscle), connective tissue (such as tendon or cartilage), or bone. Rhabdomyosarcoma usually begins in muscles that are attached to bones and that help the body move, but it may begin in many places in the body
Osteogenic sarcoma
Ewing sarcoma
Wilms Tumor
Hodgkin Disease:
- a disorder of the lymphoid system, usually arises in a single lymph node or an anatomic group of lymph nodes
-
h. Neuroblastoma
Neuroblastoma is a cancer that starts in certain very early forms of nerve cells, most often found in an embryo or fetus. (The term neuro refers to nerves, while blastoma refers to a cancer that starts in immature or developing cells)
i. Retinoblastoma
.
Pediatric cancer
def: a group of chronic diseases characterized by uncontrolled growth and spread of abnormal cells which, if not treated adequately, results in the death of the child
chronic=dt length of tx & long term complications rt tx
childhood is a treatable and cure is a realistic goal!
Cancer
def: genetic, permanent mutation of DNA
-inherited mutation or caused by external toxins
causing abnormal cellular growth, altered cell begins to multiply as directed by the altered genetic structure of the DNA and the absence or inactivation of tumor suppressor gene
Etiology:
Cause of cancer (child) = unknown (most cases)
-rt peak growth periods = certain cancers are associated with certain ages
-possibly rt environmental agents
ex. chemicals, pesticides, viruses (ex EBV virus in African Burkitt’s lymphoma), electromagnetic fields (ex. high tension wires near schools)
-reassure the parents that the cancer was NOT caused by anything anyone did/failed to do
things that are abnormal rt cell growth
Lack of cell differentiation: cells remain immature and fail to do the work of a normal cell
Loss of contact inhibition: normal cells stop dividing when they come in contact with other cells, but cancer cells crowd out normal cells
Unregulated growth: cancer cells multiply out of control dt a lack of feedback mechanism that normal cells have
Cellular immortality: failure of apoptosis/intrinsic suicide program
- apoptosis is a preprogrammed proccess used to rid the body of cells that have been damaged beyond repair
Proto-Oncogenes: Proto-oncogenes normally regulate cell growth and development. When altered by a virus or other external cause, it can change to an oncogene which allows unregulated genetic activity -> tumor growth
Oncogenes: are activated thru mutation of a proto-oncogene and allow uncontrolled cell growth. Have been identified in leukemia, lymphoma, and some solid tumors
Tumor-suppressor genes: tumor-suppressor genes normally regulate the effects of oncogenes to decrease widely proliferating cancer cell growth
Arise from genes that normally suppress cancer formation but have lost their suppressor function -> uncontrolled growth.
Have been identified in osteosarcoma, rhabdomyosarcoma, leukemia, retinoblastoma, and Wilms tumor
Children at increased risk for cancer
GENETIC PREDISPOSITION
-down syndrome
-Li-Fraumeni syndrome
-retinoblastoma gene
IMMUNODEFICIENCY
-congenital/acquired ex AIDS
-treatment-related ex. immunosuppressive drugs
HX OF CANCER/PRIOR CANCER TX
-risk for second malignancy
Classification of childhood cancer
- Hematological malignancies
- Solid tumors
-within these, tumors are named based on the type of tissue and/or site that cancer develops in
hematologic cancers -> “liquid tumors” (ex. ALL, AML, lymphomas in lymph)
Tissue Classification
Developing embryo has 3 germ cell layers:
1. ectoderm (becomes hair, nails, skin, mouth, nose, anus)
2. mesoderm (becomes blood vessels)
3. Endoderm (respiratory, GI) (inner layer)
most childhood cancers arise from the ecto or mesoderm (tissues deep in the body)
vs
most adult cancers raise from epithelial cells in the endoderm (tissues exposed to the environment)
therefore don’t see skin/GI cancers in children
structures arising from the 3 embryonal tissues
- Ectoderm
-outermost
-epidermis and epidermal tissues
-CNS (brain, spine, meninges) - Mesoderm
-middle layer
-epithelial cells of blood vessels
-blood, bone, muscle, lymphatics, pleura, heart, kidneys, gonads - Endoderm
-inner layer
-epithelium
-epithelium, GI tract, thyroid
childhood cancers - ecto & meso
adult cancers - endo
common types of childhood cancer
Hematological - mesoderm
ex. leukemia (blood/marrow)
lymphoma (lymph)
Solid tumors
ex. CNS tumors (brain, spine)
neuroblastoma (SNS)
Wilms tumor (kidney)
rhabdomyosarcoma (muscle)
retinoblastoma (eye)
Ewing’s sarcoma, osteosarcoma (bone)
Leukemia
leuk = white/ emia = blood
malignancy of blood-forming tissues (malignant transformation of bone marrow progenitor cells)
ALL = acute lymphocytic or acute lymphoblastic
AML = acute myeloid (or myelogenous) leukemia
malignant cell = “blast”
blasts in leukemia:
-fail to mature
-crowd normal cells
normally, the bone marrow manufactures precursors that will form healthy RBC, WBC, and platelets.
in leukemia, the blasts fail to mature, don’t do the normal job of WBC’s, continue to divide, and crowd the bone marrow space = fail to allow production of normal precursors.
Dx occurs when blast cells move to peripheral blood
(highlighted) bone marrow involvement symptoms:
-fatigue
-fever
-petechiae
Types of childhood lymphoma
lymphatic system - germ-fighting network
- HODGKIN DISEASE
-most common 15-19 yr
-large cancerous cells called “Reed-Sternberg (RS) cells - NON-HODGKIN DISEASE
-can occur at any age
-do not have RS cells
-under these 2 categories, there are 70+ types of lymphoma
-lymphomas can affect any portion of the lymphatic system:
ex bone marrow, thymus, spleen, tonsils, lymph nodes
Symptoms of lymphoma:
-none in early stages
-large soft lymph nodes in the neck, upper chest, armpit, stomach, groin
-chills, couch, fatigue, fever
-enlarged spleen
-itchy rash
-SOB
-nigh sweats
-stomach pain
-loss of appetite
-unexplained weight loss
Brain tumors
-location determines symptoms and indicates what type the tumors is = helps predict prognosis
-brain tumors dev when normal or abnormal cells within the brain/spinal cord multiply when not needed or grow without control mechanisms
-2 main categories of brain tumors: primary & metastatic
- Primary
-arise from normal cells in the brain
-benign or malignant - Metastatic
-originate outside the CNS
-spread by hematogenous 9thru the blood) to the CNS
-always malignant
-symptoms = primary dx or relapse
-metastatic has poor prognosis
-tx is difficult for the brain because not all chemo drugs cross the blood-brain barrier
Tumor grading
Benign:
-histologically looks like typical of the cell of origin
-do not look like cancer under microscope
-minimal/no mitosis or necrosis
-slow growing /low grade
-localized (do not invade areas outside site of origin but may be considered malignant by location)
-chemo doesn’t work well because chemo targets fast-growing cells
Malignant: (for brain tumors)
-look like cancer under microscope
-greater differentiation
-greater mitosis, necrosis
-fast growing/high grade
-invades surrounding brain tissues
-may metastasize to other areas of CNS
-may metastasize to other areas of the body
Neuroblastoma
tumors arising from neural crest tissue
ex SNS
adrenal gland
dx made after metastasis
occurs in infants, toddlers, preschoolers
-cells of the tumor are primitive neuroblasts that differentiate into neuroblastoma
-originates in abd, base of spinal column or adrenal gland
-slow growing = not dx until end-stage
-very treatable is found early
-solid tumors may present with abd swelling or pain
-the younger you are = better you will do
-if found early in baby, tumor is removed, then no further chemo because body fights off cancer and goes away. NO OTHER cancer does this
-5% long term survival is found at age 3
-none service more than 10 yrs
-survival rates ~40%
-exclusively a pediatric cancer
Wilm’s Tumor
-most common primary malignant renal tumor
-(highlighted) avoid palpating abd dt risk of spreading cancerous cells
-rapidly growing, vascular, fragile gelatinous capsule
-females>males
-peak age 2-3 yr
-75% by age 5, more likely to be advanced and have unfavorable histology
-often abd tumors present with pain, increased BP (if pressing on kidneys), constipation
-if toddler stops walking = pain = disease in bone marrow
-prognosis rt whether or not it is encapsulated = DO NOT PALPATE
-usually only affects 1 kidney
-nephrectomy - if bilateral, will remove the worst one
-I-V stages
Rhabdomyosarcoma
def: malignant tumor of embryonic muscle forming mesenchyme
-characterized by ptosis and swelling (drooping of upper eyelid)
-most common soft tissue sarcoma of childhood
-arise primarily in striated muscle tissue
-because immature mesenchyme cells also normally mature into smooth muscle, fat, fibrous tissue, bone, and cartilage = these tumors can occur anywhere in the body
histologic types and incidence;
-embryonal 60%
-aveolar 20%
other 20%
Osteogenic Sarcoma (OS)
def: malignant tumor of the bone, derived from bone-forming mesenchyme (connective tissue)
-results from malignant proliferation cellular stroma causing bony destruction by producing osteoid tissue or immature bony growth
-most common sites are in large, long bones at metaphyses (ends near growth plates):
ex. distal femur
proximal tibia
proximal humerus
-often present with fracture
-Terry Fox had this type of cancer
Tx:
-chemo to shrink tumor
-surgery to remove tumor
-may need amputation or rotation plasty
(knee becomes heel with fully functioning joint)
Ewing Sarcoma
def: bone tumor infiltrating surrounding soft tissue
-tumor originates outside the bone, with or without bony involvement
-common sites:
central axis - head/neck, chest wall, spine, pelvis
extremities (middle) - femur, tibia/fibula, other
Retinoblastoma
(highlighted) def: childhood cancer that demonstrates patterns of family inheritance
-8th most common childhood cancer
-90% dx by age 5
-20-30% bilateral
-most bilateral disease dx <12 mon
-median bilateral disease dx 18-30 mon
-rare after 6 yr
-no sex/race preference
-presentation:
-leukocoria “cat’s eye reflex” white reflection in pupil
-strabismus (cross eye)
-inflamed/painful eye
-can rarely save the eye
when discussing survival statistics, doctoress use a number called the 5-year survival rate
5 year survival rate refers to the % of patients who live past 5 years after their cancer is dx
-type of cancer important in estimating
Long-term outcomes
LEARNING PROBLEMS
-radiation and chemo affect the brain
SLOWED/DELAYED GROWTH & DEVELOPMENT
HEART OR LUNG PROBLEMS
CHANGES IN SEXUAL DEVELOPMENT /FERTILITY
-males post-puberty may be offered option of sperm banking
-females may receive HRT
INCREASE RISK OF OTHER CANCERS LATER IN LIFE
-chemo, antibiotics -> hearing loss
-radiation to teeth/jaw-> teeth problems
Differences between childhood vs adult cancer
CHILDREN:
-cancer is rare
-primary site: tissues (hematopoietic, lymph tissue, bone, muscle, CNS tissue)
-stage at dx: 80% disseminated (spread)
-response to chemotherapy: very responsive
-prevention: unlikely
-outcome: >70-90% 5-year survival
-child tumors are highly chemosensitive, may tolerate higher doses of chemo and have less difficulty with acute toxicity than adults but more vulnerable to long-term consequences
-long-term consequences therefore try to AVOID RADIATION especially to brain/head
ADULT:
-cancer is common
-primary sites: organs (breast, prostate, colon, lung)
-stage at diagnosis: local or regional
-response to chemo: less responsive
-prevention: 80% are preventable
-outcome: <60% 5-year survival
