Hi Dc-9, it must be a distressing time for you and the Mrs.
Vulval cancer is rare, I had a quick search and about 1000 women per year are affected in the UK.
The purpose of the CT scan is to see is to reveal the extenct of the cancer.
On a positive note, the prognosis is good when caught early enough, and your wife has youth on her side, which will help with subseqent treatment.
You'll probably have a thousand questions to ask on Wednesday, these people are good at translating the medical babblygook to something meaningful. They should have a base in the hospital.
Cancer Care and Support Charity - Macmillan Cancer Support
Keep us updated, I know that some experts in the field browse these pages often.