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how does a malignant tumour spread
Local invasion
Metastasis
Implantation
What is local invasion
Tumor invades surrounding tissue by destroying tissue so tumour can grow
Effects of local invasion
Can erode bone
Margin is ill defined and irregular
When local invasion has occurred can surgery be used
yes but with a large margin, so no tumour cells are left to regrow.
Usually followed with RT to make sure all cells are gone
If critical structures are involved then surgery may not be an option
if metastatic disease has occurred….
could make the tumour inoperable so will only be used to debulk the tumour
3 types of metastasis
Lymphatic vessels
Blood vessels
Across cavities
lymphatics metastasis process
Penetrates thin lymph wall
Travels downstream
Lodges in one or more local lymph nodes
If the cell survives, then proliferates in the node a metastasis is formed
Blood vessel metastasis proces
invade thin wall blood vessels
fragments float downstream passively
lodge in the next capillary bed - forming metastases
most common sites of blood metastasis …..
skin liver lungs brain bone
metastatic spread across cavities
Transcoelomic spread (across the peritoneal cavity) Penetrates the wall of a cavity
what is the peritoneum
serous membrane, lines the abdominal cavity
covers most organs
it is a layer of mesothelium suported by a thin layer of connective tissue
serves as a duct for blood and lymph vessels and nerves
Layers of the peritoneum
Outer = parietal (attaches to abdominal and pelvic walls)
inner is also thinner = visceral (wrapped around internal organs)
Space between the peritneum
filled with serous fluid so that the two layers can slide over each other
can tumour cells travel in the space between the perioteum
yes
what if there is not enough space in the cavity for tumour fragemtns to flow
The tumour will then bind the layers of tissue together
this will then cause a build up of fluid
