How Cancer Spreads.

Think of London as an overcrowded uncontrolled population of humans. Humans are like the cells that make up a cancer. Think of London as a primary cancer. I think of it as being an aggressive prostate cancer that wishes to progress but it could be any type of cancer. During the 1700’s and 1800’s, boats set sail across the oceans to find new lands to conquer. Initially, the journey provided many hazards to prevent these boats reaching their destination just in the same way that our blood stream and lymphatic channels have defences that destroy cancer cells as they enter into the circulation. Over time, new skills were acquired such as better boats, better sailing practices and the ability to fight journey related diseases such as scurvy. In a similar way, cancer cells entering into the circulation develop new skills to overcome the defence mechanisms in the circulation by mutations and are eventually able to reach their destination afar. 

Once the boats reached their destination, Sydney in Australia being a perfect example, there were local challenges to be overcome in order to survive and grow. These included food and water supply as well as battling a hostile indigenous population. This is a similar situation to when cancer cells attempt to implant at a place distant to their primary location after surviving and travelling throughout the circulation. When prostate cancer arrives in bone, the immediate instinct of bone is to mount an attack against the foreign invaders.  In a similar way to acquiring the skills to survive and travel through the circulation, the cells must now acquire the skills to overcome the local host defence mechanisms.  When this occurs, the cells are able to set up a colony and expand and gradually consume the host organ as they had done to the primary organ. 

When we look at the population of humans under the microscope during the period of British colonisation, the humans in London look the same as in Sydney.  When we look at cancer cells from the primary and compare them to the ones seen in the secondary or metastasis, they likewise look the same. 

To recap the British colonisation model for metastasis, London is the primary cancer, the oceans the circulation, and Sydney a secondary cancer or in other words a metastasis of London.