Is It Normal To Have Both Invasive And Non-Invasive (In-Situ) Breast Cancer In The Same Tumor?

— -- Question: Is it normal to have both invasive and non-invasive (in-situ) breast cancer in the same tumor?

Answer: Very often, invasive breast cancer -- the kind that spreads into the surrounding tissue -- arises from pre-existing, non-invasive breast cancer. So we will commonly see DCIS, or ductal carcinoma in situ -- which is a non-invasive form of breast cancer -- with some parts of it actually turning into invasive cancer, spreading into the tissues of the breast. This is important because it's the invasive component that stands a chance of spreading to other parts of the body.

Sometimes we see invasive cancer without pre-existing, non-invasive cancer, and that's important too. The important part of all of this is that we have to remove all the cancer, whether it's invasive or non-invasive, and in doing so, we limit the chance of the cancer coming back in the breast or in other parts of the body.

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