It is now well demonstrated that cancer surgery can promote the growth and spread of the tumour. There is data emerging however, showing that surgery increases the risk of cancer in people without clinical cancer.
Many of us have undetectable microscopic cancers. They are called occult tumours and are very common in the general population. They are maintained in a dormant state by a healthy immune system and a delicate balance between cell proliferation and cell death. They can remain undetected and dormant for a considerable amount of time, even for a lifetime. Most tumours are thought to arise from microscopic tumours that break out of dormancy. Angiogenesis seems to be a critical factor. Tumours cannot grow beyond 1-2 mm in size without initiating angiogenesis.
Surgery is a severe trauma that creates an abrupt and severe metabolic alarm response. The levels of noradrenalin and adrenalin surge activating β2-adrenergic receptors which increase vascular endothelial growth factor. This can initiate tumour angiogenesis and is called the angiogenic switch. Animal studies show occult tumour growth inititation with surgery can be blocked with drugs that block the β2-adrenergic receptors. This alone can end tumour dormancy.
The catecholamine surge is also accompanied by high coritsol which can persist for several days. The combination of these impairs cell-mediated immunity at a crucial time and allows the tumour to both break dormancy and also to travel in the blood causing micrometastases. It is an interesting concept that tumours require an abrupt change to break dormancy. It is called the Spike Hypothesis. A search for Tumour Dormancy or the Spike Hypothesis brings up quite a few good articles.
Takeaway: Several implications. One is that we can’t take surgery too lightly. It is associated with many risks however tumour risk is not often considered. Also, other traumas will create the same conditions for initiation. Presurgical care to support immune activity and enable appropriate HPA response may reduce these and other complications.
Others references;
Almog N. Molecular mechanisms underlying tumor dormancy. Cancer Lett. 2010 Aug 28;294(2):139-46
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Fascinating and scary stuff. I might have to reconsider plastic surgery! (Just kidding).
I’ve missed your articles Brendan.