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Does surgery cause cancer to spread?

The claimPhoto of a surgical operating room

Surgery causes cancer to spread to other parts of the body during a biopsy, or by exposing a tumour to air.

The truth

Surgery does not cause cancer to spread.

Sometimes, during surgery, the surgeon determines that the cancer is more advanced than doctors originally thought. The cancer was already there, but original tests did not show its extent.

There is an extremely low chance that a biopsy will cause cancer to spread. Some tumours can’t be safely biopsied without spreading cancer cells. This is sometimes referred to as seeding of tumour cells. In these cases, doctors avoid core biopsy. The tumour is completely removed without taking a biopsy.

There is no evidence that exposing a tumour to air causes it to grow more rapidly or spread to other parts of the body.

The Canadian Cancer Society is committed to sharing important information about cancer risk to Canadians and will continue to monitor research in this area.


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