News at Medicine - July 2012 - The impact of screening in families with Lynch Syndrome


The impact of screening in families with Lynch Syndrome
July 24, 2012

Lynch Syndrome is an infrequent but important cause of colorectal cancer and of gynecologic cancer because it is an inherited condition caused by mutations in mis-match repair genes. Susan Stuckless, a PhD candidate supervised by Drs. Patrick Parfrey and Jane Green, has recently published two papers in the journal Clinical Genetics, in which she examined the impact of screening for these two cancers.
 

 

First degree family members of patients with Lynch Syndrome are at 50 per cent of inheriting the mutation, and those who inherit the mutation are at substantially increased life-time risk of developing colorectal cancer and specific cancers outside the colon, particularly gynecologic cancer in females.

The papers authored by Ms. Stuckless examine the impact of colonoscopic screening in preventing colorectal cancer by polyp removal, and of gynecologic screening in diagnosing endometrial or ovarian cancer at an early stage, in 322 mutation carriers among multiple large families with Lynch Syndrome.

In unscreened male carriers, 50 per cent had developed colorectal cancer by age 47 years, and 50 per cent had died by age 62. However, in males who entered a screening colonoscopy program, the age of diagnosis of colorectal cancer was delayed by 11 years and survival improved by four years. 

In females the results were even better. In unscreened females 50 per cent had developed colorectal cancer by age 57 years and 50 per cent had died by age 63 years, whereas in screened females age of diagnosis of colorectal cancer was delayed by over 20 years, and average survival was 80 years. Gynecologic screening did not result in earlier detection of gynecologic cancer.

It was concluded that colonoscopic screening in mutation carriers reduced cancer risk and improved survival, particularly in females, and that gynecologic screening did not result in earlier gynecologic cancer detection. Despite screening some young women died from ovarian cancer suggesting that prophylactic hysterectomy with bilateral Salpingo-oophorectomy be considered in female mutation carriers who have completed childbearing.