HNPCC

Hereditary non-polyposis colorectal cancer (HNPCC) is an inherited disorder and is one of the most prevalent cancer syndromes in humans. Although colorectal cancer is the ‘hallmark’ disease, other cancers which occur outside of the colon are also part of the syndrome. Endometrial/womb cancer is the second most common of these cancers.

The syndrome is characterised by early onset of cancers, with an average age at diagnosis of 45 years; multiple cancers can occur at various ages at different times.

Endometrial cancer is the most common gynaecological cancer in the Western world. However, the general population risk of developing it is only 3%, and it usually presents in postmenopausal women. In contrast, endometrial cancer associated with HNPCC presents in younger women, with most women experiencing the disease between 40 and 60 years of age.

A thorough family history is required to identify those at an increased risk of developing a gynaecological malignancy.

Diagnosis of HNPCC

In order to make a diagnosis of HNPCC there must be at least three relatives with an HNPCC-associated cancer (colorectal, endometrium, small bowel, ureter or renal pelvis), and all of the following criteria must be met:

• The patient should be a first degree relative of the other two
  
• At least two successive generations must be affected
  
• At least one cancer diagnosed of the 3 must have been diagnosed before the age of 50
  
• Familial polyposis must be excluded in the colorectal case (if present)
  
• The tumour must be verified by pathology
  

Genetic testing

Genetic testing has a significant role in confirming a diagnosis of HNPCC and screening of family members.

If you are concerned that you may belong to a family that fits the above criteria you could discuss this further with your GP or practice nurse. If they feel that a referral is appropriate you will receive an appointment with your local genetic department. If the genetic department feels you should be monitored on a regular basis then this will involve annual colonosopy (colorectal screening) and annual transvaginal scans (endometrial screening).