Low Incidence of Hereditary Nonpolyposis Colorectal Cancer Syndrome in a Selected Area of the Lombardy Cancer Registry

Estimated prevalence of hereditary cancers and the need for surveillance in a Norwegian county, Telemark

OBJECTIVE

The aim of the study was to estimate the prevalence of hereditary cancers and the need for surveillance in Telemark county, Norway.

MATERIAL AND METHODS

All persons attending the Norwegian Colorectal Cancer Prevention (NORCCAP) trial in Telemark were interviewed about cases of cancer in the family. Diagnoses were verified, pedigrees constructed and families classified according to preset criteria aiming at identifying hereditary cancer. Mutation analyses were performed in kindreds at risk for breast cancers when possible. Immunohistochemistry of tumors in assumed inherited colorectal cancer families was undertaken.

RESULTS

The screening examination was attended by 7,224 persons among whom 2,866 had cancer in the family. Of these, 2,479 had no suspicion of any known inherited cancer syndrome. Family information questionnaires were mailed to 387 persons and returned by 191. Sixty-four of these 191 met the clinical criteria for familial cancer by family history after verification of diagnoses. Observed prevalences for being at risk for hereditary breast and breast-ovarian cancer (HBOC) or hereditary non-polyposis colorectal cancer (HNPCC) were 2.8 per thousand and 0.77 per thousand, respectively.

CONCLUSIONS

The number of colonoscopies and mammograms obtained per year serving those who needed them was limited and reduced by clinical genetic work-up from 2,866 with a family history of cancer to 64 proven cases. Continued surveillance of an unnecessarily high number leads to unjustified cancer worry, is costly and uses up health-care facilities. Genetic work-up is a one-time job that reduces input numbers to surveillance programs, provides a starting-point for mutation testing and is economically cost beneficial if inherited cancers are prevented or cured by the health-care programs offered.

Identification of predictive factors for the occurrence of predisposing MLH1 and MSH2 germline mutations among Sardinian patients with colorectal carcinoma

Factors predictive of carrying MLH1 and MSH2 germline mutations in patients with colorectal cancer (CRC) are as yet unknown. The aim of this population-based study, was to further define the role of MLH1/MSH2 mutations through an evaluation clinic program with 362 consecutive Sardinian CRC patients. Eight MLH1/MSH2 germline mutations were detected in 21 (6%) patients. Examining family cancer history, MLH1/MSH2 mutations were found in 14/48 (29.2%) probands from CRC families and, among them, in 10/13 (76.9%) families fulfilling the Amsterdam criteria. The patients with low familial recurrence (two CRCs in the family) presented a much lower frequency of MLH1/MSH2 mutations (2/55; 3.6%). Significantly higher rates of MLH1/MSH2 mutations were found in patients with age of onset 45 years (P=0.012) or with 3 affected family members (P=0.009). While no significant predictive value was found for the presence of endometrial cancer within the family, earlier age of diagnosis and/or familial CRC recurrence should be considered as strong predictors for the occurrence of MLH1/MSH2 mutations, and therefore useful in recommending CRC patients for genetic testing.

Putative common origin of two MLH1 mutations in Italian-Quebec hereditary non-polyposis colorectal cancer families

Hereditary non-polyposis colorectal cancer (HNPCC) is one of the most common inherited cancer syndromes, accounting for 3-5% of all cases of colorectal cancer. In most HNPCC families, the disease is caused by a germline mutation in MLH1 or MSH2. In some populations, founder mutations appear to explain a substantial fraction of HNPCC. We report here the identification and preliminary characterization of two putative MLH1 founder mutations. The mutation MLH1c.1831delAT was shown to segregate in two Quebec families of Italian origin who fulfilled the Amsterdam criteria for HNPCC. Haplotype analysis using five intragenic microsatellite/single nucleotide polymorphism markers spanning MLH1 on chromosome 3 showed that these two unrelated families share an identical haplotype. In addition, two other Italian kindred whose affected members carry MLH1g.IVS6 + 3A>G also share a common haplotype, suggesting that, similarly, the latter mutation has a common origin. These mutations are the first putative founder MLH1 mutations to be identified in HNPCC kindred of Italian origin.

Frequency of hereditary non-polyposis colorectal cancer and other colorectal cancer familial forms in Spain: a multicentre, prospective, nationwide study

BACKGROUND

Colorectal cancer is the third leading cause of cancer mortality in Western countries. Hereditary nonpolyposis colorectal cancer is the most common type of hereditary colorectal cancer, but its incidence remains controversial, ranging from 1 to 5%.

OBJECTIVE

This present prospective, multicentre, nationwide study was aimed at compiling prominent epidemiological and clinical data with respect to hereditary non-polyposis colorectal cancer and other familial colorectal cancer forms in Spain, where information is lacking.

METHODS

All patients with a de-novo diagnosis of colorectal cancer and who attended between November 2000 and October 2001 in 25 hospitals all over Spain were registered. Demographic, clinical and tumour-related characteristics of probands, and detailed family history, were obtained.

RESULTS

A total of 1872 colorectal cancer patients were included. Clinical diagnosis of hereditary non-polyposis colorectal cancer was established in 46 (2.5%) patients according to the Amsterdam II criteria. Comparison between patients fulfilling either the Amsterdam I or the Amsterdam II criteria revealed no differences with respect to demographic, clinical and tumour-related characteristics. A total of 504 (27.0%) patients had a family history of hereditary non-polyposis colorectal cancer-related neoplasm not fulfilling the Amsterdam criteria (familial colorectal cancer), while 360 (19.2%) patients fulfilled at least one of the Bethesda's criteria.

CONCLUSION

These clinicoepidemiological data provide a more accurate characterization of hereditary non-polyposis colorectal cancer and other familial colorectal cancer forms in Spain, with potential implications in preventive strategies.