Kate Middleton has cancer undergoing 'preventative chemotherapy' - but what does it mean?

Very concerning news from the Princess of Wales was announced today. It's very brave of her to share this publicly. It must be hard enough to deal with the physical and emotional distress of a diagnosis of cancer without having to cope with media speculation and innuendo.

It takes time to digest a diagnosis of cancer and it's completely understandable that Kate wanted to make sure her children heard it from her and, no doubt, Prince William, first and when they knew what they were dealing with.

As an oncologist, working in a multidisciplinary team (MDT), I often have to explain it takes time (often weeks) to establish a plan of management. The Princess would have had to have undergone numerous investigations such as CT scans, PET scans and blood test to see if there is evidence of spread and to establish a stage (how advanced it is).

The cancer specimen would have been scrutinised, in detail, by the histopathologist to determine the particular type of cancer, the grade (how aggressive it is) and what specific mutations the cancer DNA has developed - all of these factors combined would help determine the next treatment options and the choice of drugs.

When all this information is gathered, and the details are discussed by the whole MDT, a management plan is determined. Only after that, this would have been discussed with the Princess and her family.

We have not been told what type of cancer Kate has but it must be quite serious if she has been advised chemotherapy. The most likely cancers would be those arising from the bowel, ovary or uterus, in that order.

The reassuring news is that Kate has announced she is receiving preventative chemotherapy. Another name for this is adjuvant which means it is given in addition to the main treatment - in this case her surgery.

The surgeon, therefore, must be relieved that he or she has removed all the visible tumour and there is no evidence of distant spread. This tells us that Kate must be on the curable pathway.

Adjuvant or preventable chemotherapy then aims to improve the odds of the cancer not coming back in the future. It works by mopping up (killing) small clusters of cancer cells which may have spread in the months before surgical removal.

In general the more advanced and more aggressive the tumour, the more likely preventative chemotherapy or other biological therapies are necessary. Likewise, these factors determine the odds of relapse of the cancer returning after cancer treatments are finished.

Chemotherapy is not an easy treatment to receive, has many risks and side effects. The fact that she is previously fit and exercises regularly is certainly in her favour - We hope it goes as well as can be expected.