Worldwide Practice Patterns in Lynch Syndrome Diagnosis and Management, Based on Data From the International Mismatch Repair Consortium

BACKGROUND & AIMS

Families with a history of Lynch syndrome often do not adhere to guidelines for genetic testing and screening. We investigated practice patterns related to Lynch syndrome worldwide, to ascertain potential targets for research and public policy efforts.

METHODS

We collected data from the International Mismatch Repair Consortium (IMRC), which comprises major research and clinical groups engaged in the care of families with Lynch syndrome worldwide. IMRC institutions were invited to complete a questionnaire to characterize diagnoses of Lynch syndrome and management practice patterns.

RESULTS

Fifty-five providers, representing 63 of 128 member institutions (49%) in 21 countries, completed the questionnaire. For case finding, 55% of respondents reported participating in routine widespread population tumor testing among persons with newly diagnosed Lynch syndrome-associated cancers, whereas 27% reported relying on clinical criteria with selective tumor and/or germline analyses. Most respondents (64%) reported using multigene panels for germline analysis, and only 28% reported testing tumors for biallelic mutations for cases in which suspected pathogenic mutations were not confirmed by germline analysis. Respondents reported relying on passive dissemination of information to at-risk family members, and there was variation in follow through of genetic testing recommendations. Reported risk management practices varied-nearly all programs (98%) recommended colonoscopy every 1 to 2 years, but only 35% recommended chemoprevention with aspirin.

CONCLUSIONS

There is widespread heterogeneity in management practices for Lynch syndrome worldwide among IMRC member institutions. This may reflect the rapid pace of emerging technology, regional differences in resources, and the lack of definitive data for many clinical questions. Future efforts should focus on the large numbers of high-risk patients without access to state-of-the-art Lynch syndrome management.

Brief report: genetics of alcoholic cirrhosis-GenomALC multinational study

Background

The risk of alcohol‐related liver cirrhosis increases with increasing alcohol consumption, but many people with very high intake escape from liver disease. We postulate that susceptibility to alcoholic cirrhosis has a complex genetic component and propose that this can be dissected through a large and sufficiently powered genomewide association study (GWAS).

Methods

The GenomALC Consortium comprises researchers from Australia, France, Germany, Switzerland, United Kingdom, and United States, with a joint aim of exploring the genetic and genomic basis of alcoholic cirrhosis. For this National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism funded study, we are recruiting high‐risk drinkers who are either cases (with alcoholic cirrhosis) or controls (drinking comparable amounts over similar time, but free of significant liver disease). Extensive phenotypic data are obtained using semistructured interviews and patient records, and blood samples are collected.

Results

We have successfully recruited 859 participants including 538 matched case–control samples as of September 2014, using study‐specific inclusion–exclusion criteria and data collection protocols. Of these, 580 are cases (442 men and 138 women) and 279 are controls (205 men and 74 women). Duration of excessive drinking was slightly greater in cases than controls and was significantly less in women than men. Cases had significantly lower lifetime alcohol intake than controls. Both cases and controls had a high prevalence of reported parental alcohol problems, but cases were significantly more likely to report that a father with alcohol problems had died from liver disease (odds ratio 2.53, 95% confidence interval 1.31 to 4.87, p = 0.0055).

Conclusions

Recruitment of participants for a GWAS of alcoholic cirrhosis has proved feasible across countries with multiple sites. Affected patients often consume less alcohol than unaffected ones, emphasizing the existence of individual vulnerability factors. Cases are more likely to report liver disease in a father with alcohol problems than controls, consistent with a potential genetic component to the risk of alcoholic cirrhosis.

Undiagnosed diabetes and impaired fasting glucose in HFE C282Y homozygotes and HFE wild-type controls in the HEIRS Study

OBJECTIVE

To determine prevalences and predictors of undiagnosed diabetes mellitus (UDM) and impaired fasting glucose (IFG) in non-Hispanic whites with HFE p.C282Y homozygosity and controls without common HFE mutations identified in population screening.

RESEARCH DESIGN AND METHODS

We analyzed these observations in a postscreening examination: age; sex; body mass index; systolic/diastolic blood pressure; metacarpophalangeal joint hypertrophy; hepatomegaly; blood neutrophils; alanine and aspartate aminotransferase; elevated C reactive protein; transferrin saturation; serum ferritin; and Field Center.

RESULTS

There were 223 p.C282Y homozygotes and 449 controls without diagnosed diabetes (43.9% men). Mean age of p.C282Y homozygotes was 52±13 years (controls 57±14 years; p<0.0001). Mean transferrin saturation in p.C282Y homozygotes was 67±26% (controls 34±14%; p<0.0001). Mean serum ferritin in p.C282Y homozygotes was 607 pmol/L (95% CI 497 to 517; controls 274 pmol/L (247 to 301); p<0.0001). Overall prevalences of UDM (4.0% vs 4.2%) and IFG (23.8% vs 25.6%) did not differ significantly between p.C282Y homozygotes and wt/wt controls, respectively. In logistic regressions, male sex, body mass index, and alanine aminotransferase were significantly associated with UDM. ORs were 2.7 (1.2 to 2.8); 1.0 (1.0 to 1.1); and 1.0 (1.0 to 1.0), respectively. Age, male sex, and body mass index were significantly associated with IFG. ORs were 1.0 (1.0 to 1.1); 2.8 (1.9 to 4.2); and 1.0 (1.0 to 1.1), respectively.

CONCLUSIONS

Prevalences of UDM and IFG were similar in p.C282Y homozygotes and controls in a postpopulation screening examination. Male sex was the strongest predictor of UDM and IFG.

Incidence and mortality of colorectal cancer in individuals with a family history of colorectal cancer

BACKGROUND & AIMS

Little is known about the change in risk conferred by family history of colorectal cancer (CRC) as a person ages. We evaluated the effect of family history on CRC incidence and mortality after 55 years of age, when the risk of early onset cancer had passed.

METHODS

We collected data from participants in the randomized, controlled Prostate, Lung, Colorectal and Ovarian cancer screening trial of flexible sigmoidoscopy versus usual care (55-74 years old, no history of CRC), performed at 10 US centers from 1993 to 2001. A detailed family history of colorectal cancer was obtained at enrollment, and subjects were followed for CRC incidence and mortality for up to 13 years.

RESULTS

Among 144,768 participants, 14,961 subjects (10.3%) reported a family of CRC. Of 2090 incident cases, 273 cases (13.1%) had a family history of CRC; among 538 deaths from CRC, 71 (13.2%) had a family history of CRC. Overall, family history of CRC was associated with an increased risk of CRC incidence (hazard ratio [HR], 1.30; 95% confidence interval [CI], 1.10-1.50; P<.0001) and increased mortality (HR, 1.31; 95% CI, 1.02-1.69; P = .03). Subjects with 1 first degree relative (FDR) with CRC (n = 238; HR, 1.23; 95% CI, 1.07-1.42) or ≥2 FDRs with CRC (n = 35; HR, 2.04; 95% CI, 1.44-2.86) were at increased risk for incident CRC. However, among individuals with 1 FDR with CRC, there were no differences in risk based on age at diagnosis in the FDR (for FDR <60 years of age: HR, 1.27; 95% CI, 0.97-1.63; for FDR 60-70 years of age: HR, 1.33; 95% CI, 1.06-1.62; for FDR >70 years of age: HR, 1.14; 95% CI, 0.93-1.45; P trend = .59).

CONCLUSIONS

After 55 years of age, subjects with 1 FDR with CRC had only a modest increase in risk for CRC incidence and death; age of onset in the FDR was not significantly associated with risk. Individuals with ≥2 FDRs with CRC had continued increased risk in older age. Guidelines and clinical practice for subjects with a family history of CRC should be modified to align CRC testing to risk. ClinicalTrials.gov number, NCT00002540.