Introduction to Cancer
Definitions

The word “cancer” comes from the latin
word for crab.
The Greek word oncos means swelling
and where we get the word oncology or
oncologist.
 What is the Latin word for swelling?
 Tumor

Neoplasia (Gk. new growth)
“A neoplasm is an abnormal mass of
tissue, the growth of which exceeds and is
uncoordinated with that of the normal
tissues and persists in the same excessive
manner after cessation of the stimuli
which evoked the change.”
 --Dr. R. A. Willis

Benign vs. malignant
Well-differentiated - when cancer cells
resemble normal surrounding cells.
 benign
 Poorly-differentiated – when cancer cells
do not resemble normal surrounding
cells.
 malignant

benign – well-differentiated.
malignant-poorly differentiated
Benign:
grow slowly
low mitotic rate
well differentiated
not invasive; well-defined borders
remain localized; do not
metastasize
Malignant
Grow rapidly
high mitotic index
poorly differentiated
do not have a capsule
invade surrounding structures; can
metastasize
Nuclei of cells
Have an abundance of DNA and are
therefore large.
 Hyperchromatic- stain darkly

In contrast, this hepatocellular carcinoma is not as well circumscribed (note the
infiltration of tumor off to the lower right) nor as uniform in consistency. It is also
arising in a cirrhotic (nodular) liver.
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Malignant neoplasms are
also characterized by the
tendency to invade
surrounding tissues. Here, a
lung cancer is seen to be
spreading along the bronchi
into the surrounding lung.
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This is an example of metastases to the liver. Note that the tan-white masses are
multiple and irregularly sized. A primary neoplasm is more likely to be a solitary
mass. Metastasis is the best indication that a neoplasm is malignant.
Stages of cancer spread:
Stage 1 – confined to site of origin
Stage 2- cancer is locally invasive
Stage 3 – cancer has spread to
regional structures
Stage 4- cancer has spread to
distant sites
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TNM system:
tumor spread
node involvement
presence of distant metastasis
Staging may influence choice of treatment
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Staging TNM system
1.Size of tumor – T0, T1, T2,T3
2.Degree of local invasion – lymph
node involvement
3.Extent of spread – metastasis
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Patterns of spread: Metastasis
Direct or continuous extension
 By lymphatics or blood stream

◦ As clumps or as single cells
◦ Lymphatics most common
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Distribution and common sites of distant
metastases
•
often occurs in the first capillary bed
encountered
•Others show “organ tropism”
•Due to:
•Local growth factors or hormones
•Preferential adherence to the surface
•Presence of chemotactic factors
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Clinical manifestations of Cancer

Pain
◦ Usually not in early stages
◦ 60 – 80 % of terminally ill
◦ Psychogenic, cultural and physiologic
components
◦ Due to pressure, obstruction, stretching,
tissue damage or inflammation
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Clinical manifestations of Cancer
Cachexia – wasting
anorexia
early satiety
weight loss
anemia
marked weakness
taste alterations
altered metabolism
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Clinical manifestations of Cancer
Anemia
chronic bleeding
malnutrition
medical therapies
malignancy in blood forming organs
Administer erythropoietin
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Clinical manifestations of Cancer
Leukopenia and thrombocytopenia
tumor invasion of bone marrow
chemotherapy or radiation
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Cancer Treatment

Chemotherapy
◦ Cytotoxic drugs + body defenses
 Single agent
 Combination chemotherapy
Avoids single agent resistance
Can use lower dose
Better remission and cure rate
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Cancer Treatment
Radiation
targets DNA
kill tumor without damage to
surrounding tissues
tumor must be accessible
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Cancer Treatment
Surgery
method of choice
can remove entire tumor
debulking
adjuvant chemotherapy or
radiation
palliation
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