The Latest on Lynch Syndrome

Briefly Noted:

AGA Guidelines on Diagnosis and Management of Lynch Syndrome: JH Rubenstein et al. Gastroenterol 2015; 149: 777-82. Technical Review 783-813. Patient Guideline Summary 814-14.

MB Yurgelun et al. Gastroenterol 2015; 149: 604-13.  Multigene panel testing from 1260 individuals with clinical Lynch syndrome.  9% had Lynch syndrome mutations identified, 5.6% had other cancer predisposing genes (eg. BRCA1) identified, and 479 had variants of uncertain clinical significance.

Related blog post:

 

Updated Guidelines on Genetic Testing/Management for Hereditary GI Cancer Syndromes

Here’s a link to abstract: Updated Guidelines on Genetic Testing/Management for Hereditary GI Cancer Syndromes (The American Journal of Gastroenterology 110, 223-262 (February 2015) | doi:10.1038/ajg.2014.435).  This ACG guideline specifically discusses genetic testing and management of Lynch syndrome, familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (AFAP), MUTYH-associated polyposis (MAP), Peutz–Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, serrated (hyperplastic) polyposis syndrome, hereditary pancreatic cancer, and hereditary gastric cancer.

I glanced at the guideline –it is about 40 pages in length.  It provides a lot of in-depth information on these infrequent disorders.

Some online resources for similar information:

Are you familiar with CMMR-D?

In a recent review, CMMR-D and Lynch syndrome are reviewed (JPGN 2014; 58: 144-52). The term CMMR-D refers to constitutional mismatch repair deficiency.  This occurs when an individual inherits two MMR gene defects (rather than one gene defect in Lynch syndrome). CMMR-D can occur when a different mutation is inherited from each parent. MMR genes include MLH1, MSH2, MSH6 and PMS2.

Unlike Lynch syndrome when screening for colorectal cancer (CRC) usually starts at age 20 years or 5 years before first CRC in family, with CMMR-D screening recommendations include yearly endoscopic evaluation beginning at age 3 years or at diagnosis.  Complete management guidelines are listed in Table 4.

More bad news for smokers

Add two more cancer risks for tobacco smoke (Gastroenterology 2012: 142: 233-40, 242-47).  There is now evidence linking tobacco smoke to 18 different cancers and tobacco smoke is probably the most preventable cause of death in the world.

In the first study, the investigators examined 3167 patients with Barrett’s esophagus.  This retrospective study followed patients for 7.5 years.  Patients who were current smokers (any form of tobacco) had double the risk of developing high-grade dysplasia or cancer compared to those who had never smoked.  Former cigarette smokers had a hazard ratio of 1.53.

In the second study, 386 patients with Lynch syndrome were analyzed during a 10 month period.  The hazard ratio for developing colorectal adenomas was 6.13 for current smokers and 3.03 for former smokers compared with patients who never smoked.  In addition, the authors identified a trend for developing adenomas based on pack-years.

Two more reasons to quit smoking.  On a side note, my grandmother said quitting smoking was the easiest thing that she ever did.  So easy, she did it a thousand times.

Additional references:

  • -Gastroenterolgy 2005; 129: 1825-31.  1.6% incidence of BE in adult Swedish population. Alcohol & smoking increase risk.
  • -NEJM 2011; 365: 1222. Treating smokers -useful review.
  • -NEJM 2011; 365: 1193. Cytisine -inexpensive- helps with smoking cessation (8.4% success vs 2.4%in placebo)
  • -NEJM 2008 358; 2249. Smoking and role of social networks.
  • -Gastroenterology 2011; 141: 2000. Lower risk of Barrett’s in pts taking NSAIDs & statins. n=570.
  • -Gastroenterology 2011; 141: 1179. Lower risk of Barrett’s in pts with low-grade dysplasia than previously noted -similar to non-dysplastic Barrett’s.
  • -NEJM 2011; 365: 1375. Large Danish study, n=11028. Lower incidence of Barrett’s than previous estimates. Relative risk of 11.3 compared to general population for adenoca of Esophagus with absolute annual risk of 0.12%. Barrett’s patients have the same life expectancy as general population (ed. pg 1437). Detecting cancer only ~1 in 1460 scopes with screening whereas Barrett’s detected in 10% of pts.
  • -Gastroenterology 2011; 140: 1084. AGA statement on Barrett’s . Recs screening only in those with multiple risk factors (age 50, male, chronic GERD, white, incr BMI)
  • -NEJM 2005; 352: 1851. Cases of Lynch can be missed when following screening guidelines.
  • -Gastroenterology 2010; 138: 207-2177 (entire issue) Colon cancer, Lynch syndrome
  • -Gastroenterology 2008; 135: 380.  Review of colon cancer screening and prevention -2008 up-to-date- literature review
  • -Gastroenterology 1967; 53: 517-27.  Seminal article.  Lynch HT showed gene-related cancer in family cancer syndrome -different than polyposis syndromes.