If cancer hates oxygen why does it seem to spread once an operation begins?

The notion that cancer hates oxygen and spreads when exposed to it is a misconception. While some types of cancer cells can grow faster in hypoxic (low-oxygen) environments, most cancers actually thrive in the presence of oxygen.

During surgery, the disruption of tissues and blood vessels can lead to the release of growth factors and inflammatory mediators that promote cancer cell proliferation and migration. This can result in the appearance of increased cancer spread after an operation. However, it's important to note that this does not mean that the cancer was not present before the surgery.

The spread of cancer is a complex process influenced by various factors, including the type of cancer, genetic mutations, angiogenesis (the formation of new blood vessels), and the immune system's response. While the exact mechanisms are still being studied, it is generally understood that cancer cells can spread through the bloodstream (hematogenous metastasis) or the lymphatic system (lymphatic metastasis).