If a women with ovarian cancer is fit enough to have an operation, it's known that her outlook can be improved by removing as much tumour as possible in this first operation. This is true even if it's not possible to remove all of the cancer and some has to be left behind.

The majority of women with ovarian cancer are not diagnosed until the tumour is advanced and has spread beyond the ovaries. This is often because the symptoms can be quite vague and may not occur until the cancer is at an advanced stage. Ovarian cancer usually spreads in two ways. The first way is just to enlarge, and spread locally in the pelvis where the ovaries lie. The second is for cancer cells to break away from the original tumour and settle within the abdomen, where they can cause tumours to form over the surface of the bowel and other organs in the abdomen. When these tumours are large this is called bulky disease. This unique method of spread can make things difficult for the surgeon, in that the tumours can be widespread and sometimes in awkward places hindering their complete removal.

The surgeon will try to remove all the tumour that they can find, although this may not always be possible. They will then debulk the cancer, which means removing the largest tumours. There is good evidence to suggest that this initial debulking of the tumour, to leave as little as possible, is likely to increase the benefits of chemotherapy and prolong life. Certainly an operation for ovarian cancer is no small matter, but even an incomplete reduction in the bulk of cancer can help significantly. Sometimes the surgeon will find during the operation that things are too stuck down to even achieve the debulking they intended.

Occasionally ovarian cancer can spread via the bloodstream to the liver or to other organs outside the abdomen such as the lungs. In this situation debulking may not be helpful and chemotherapy is usually used on its own. But if the surgeon feels that it is possible to reduce the amount of tumour with an operation this is still usually worthwhile.