Neoplasia - Methods of spreading

Question 1

What are the methods of spreading?

Answer 1

1. Local
2. Seeding
3. Metastasis

Question 2

Local spreading?

Answer 2

Invades only the immediately surrounding tissue

Invasion & extension

Question 3

Seeding spread?

Answer 3

Distant spread that occurs only within body cavities

Question 4

Metastasis?

Answer 4

Distant spread (“true spreading”) through lymph or blood channels

Question 5

Explain how metastasis spreads?

Answer 5

As tumor advances, it makes contact with surrounding structures as well as vessels. It will go into blood or lymph. It will travel with blood/lymph until it reaches an area with resistance. (For example, if blood, it will attach to epithelium) Once cells attach, they send out mediators. It will grow or die depending on the environment

Question 6

What kind of spread is the following an example of?:

Tumor in stomach, drops through pores, land on other organs

Answer 6

Seeding

Question 7

What kind of spread is the following an example of?:

If tumor was in the lungs, there is a probability of the malignant cells dropping and landing on the diaphragm

Answer 7

Seeding

Question 8

Definition of metastasis?

Answer 8

Spread of malignant cells from primary to secondary site through blood and lymph.

Question 9

What do malignant neoplasms continue to do until they can make contact with lymph or blood channels?

Answer 9

Divide and grow

Question 10

Primary site (metastasis)?

Answer 10

Where the tumor was first formed, origin of cancer

Question 11

Secondary site (metastasis)?

Answer 11

Where the CA cells spread to and proliferate

Question 12

Sentinel lymph node?

Answer 12

first lymph node affected by cancerous cells

Question 13

Does the tissue on the secondary site (metastasized site) become malignant?

Answer 13

No, but it is invaded by malignant cells from the primary site and gives them an area to grow and divide.

Question 14

Where do malignant cells usually metastasize to?

Answer 14

Liver, lungs, bone, brain (vital organs)

Question 15

In a nut shell, what occurs in Stage 1?

Answer 15

Malignant cells secrete enzymes -> destruction

Question 16

Explain in detail what occurs in Stage 1?

Answer 16

Malignant cells begin to proliferate in local tissue [as they secrete enzymes that break up the cementing material between normal cells to make room for further proliferation]. Groups of malignant cells (emboli) enter blood or lymph vessels. Turbulence of blood distributes the cancer cells within the vessel. Defense cells attack cancer cells but approximately 1 out of every 10 000 cancer cells survive.

Question 17

What distributes the cancer cells within a blood vessel?

Answer 17

Turbulence of blood

Question 18

What aids survival of cancer cells?

Answer 18

Our own platelets, that cover the cancer cells and protect them from defenses.

Question 19

Why do malignant cells typically have a poor survival in stage 1?

Answer 19

1. Poor probability because it is getting into circulation. They encounter defense cells right away and are targeted.
2. Turbulences
3. If they go into a lymph vessel -> they go into a lump node (survival is very poor)

Question 20

In a nut shell, what occurs in Stage 2?

Answer 20

Some emboli have entered / attachment & growth at secondary site.

Question 21

Explain in detail what occurs in Stage 2?

Answer 21

Cancer spreads via. blood or lymph. Malignant cells arrive at a suitable secondary site. Cytokines help determine suitability and assist in growth. Once a suitable site is established, malignant cells use cytokines and growth factors to invade the tissue. Cells @ secondary site do not become malignant but they provide a safe space for the invading malignant cells to grow.

Question 22

To be a suitable secondary site (metastasis), what must it provide?

Answer 22

1. resources for growth and division
2. protection from defenses
3. room to grow

Question 23

What is the role of cytokines in stage 2?

Answer 23

They help determine suitability and assist in growth (area of resistance)

Question 24

Scenario: Cancer in lung -> Epithelial cells are malignant. If the cancer spreads to the liver, what occurs to the hepatocytes?

Answer 24

They do no become malignant however, that site provides and area for the epithelial cells to proliferate.

Question 25

In a nut shell, what occurs in Stage 3?

Answer 25

Cells grow & cause angiogenesis in host

Question 26

Explain in detail what occurs in Stage 3?

Answer 26

Angiogenesis occurs in host. Cancer cells need blood supply and resources to ensure survival and cell growth @ the secondary sites so they create their own blood vessels.

Question 27

What is the difference between thrombosis and embolism?

Answer 27

Thrombosis is a blood clot in vessels that is stationary. Embolism is a piece of thrombosis that breaks off and moves with blood. (Embolism is not supposed to be here but moves with blood)

Question 28

When does the secondary site become the preferred site (metastasis)?

Answer 28

If it is 1. Large

2. Richly vascularized

Question 29

What makes suitable secondary sites?

Answer 29

Lungs, liver, bone (skeleton), brain [because they are all large and have vast blood supply]