Hereditary nonpolyposis colorectal cancer: an update

Surgical treatment of hereditary nonpolyposis colorectal cancer (HNPCC, Lynch syndrome)

The surgical management of the Lynch syndrome patient with colorectal cancer needs to be individualized. Because of the increased incidence of synchronous and metachronous colorectal neoplasms, most favor an extended resection at the time of diagnosis of colorectal cancer. Age of diagnosis, stage of the tumor, co-morbidities, surgical expertise, surgical morbidity, and patient wishes should be taken into account when considering a surgical procedure. There are no prospective randomized trials or retrospective trials suggesting that patients undergoing an extended procedure have a survival advantage compared to those undergoing segmental resection. In retrospective studies it has been demonstrated that patients undergoing extended procedures will develop less metachronous colorectal neoplasms and will undergo less subsequent surgical procedures related to colorectal cancer. In females abdominal hysterectomy and bilateral salpingoophorectomy should be considered at the time of surgery for colorectal cancer.

Criteria and prediction models for mismatch repair gene mutations: a review

One of the strongest predictors of colorectal cancer risk is carrying a germline mutation in a DNA mismatch repair (MMR) gene. Once identified, mutation carriers can be recommended for intensive screening that will substantially reduce their high colorectal cancer risk. Conversely, the relatives of carriers identified as non-carriers can be relieved of the burden of intensive screening. Criteria and prediction models that identify likely mutation carriers are needed for cost-effective, targeted, germline testing for MMR gene mutation. We reviewed 12 criteria/guidelines and 8 prediction models (Leiden, Amsterdam-plus, Amsterdam-alternative, MMRpro, PREMM1,2,6, MMRpredict, Associazione Italiana per lo studio della Familiarità ed Ereditarietà dei tumori Gastrointestinali (AIFEG) and the Myriad Genetics Prevalence table) for identifying mutation carriers. While criteria are only used to identify individuals with colorectal cancer (yes/no for screening followed by germline testing), all prediction models except MMRpredict and Myriad tables can predict the probability of carrying mutations for individuals with or without colorectal cancer. We conducted a meta-analysis of the discrimination performance of 17 studies that validated the prediction models. The pooled estimate for the area under curve was 0.80 (95% CI 0.72 to 0.88) for MMRpro, 0.81 (95% CI 0.73 to 0.88) for MMRpredict, 0.84 (95% CI 0.81 to 0.88) for PREMM, and 0.85 (95% CI 0.78 to 0.91) for Leiden model. Given the high degree of overlap in the CIs, we cannot state that one model has a higher discrimination than any of the others. Overall, the existing statistical models have been shown to be sensitive and specific (at a 5% cut-off) in predicting MMR gene mutation carriers. Future models may need to: provide prediction of PMS2 mutations, take into account a wider range of Lynch syndrome-associated cancers when assessing family history, and be applicable to all people irrespective of any cancer diagnosis.

Lynch syndrome in a predominantly Afrocentric population: a clinicopathological and genetic study

BACKGROUND

We investigated the prevalence of Lynch syndrome as a hereditary cause of colon cancer in the young Jamaican colorectal cancer (CRC) population.

METHODS

We identified patients aged 40 years or younger in whom primary CRC was diagnosed at the University Hospital of the West Indies from January 2004 to December 2008. We reviewed the medical records and hematoxylin and eosin (H&E)-stained histopathology slides. Tumour blocks were tested for microsatellite instability (MSI). Patients with MSI-high phenotype (MSI-H) tumours had genetic counselling, after which genomic DNA was extracted from peripheral blood to test for MLH1 and MSH2 germline mutations. Patients also had pedigree mapping.

RESULTS

There were 25 patients with CRC aged 40 years or younger with no history of hereditary colon cancer syndrome. The patients' mean age was 33 (range 21-40) years. Histopathologic review confirmed CRC in all patients; 8 of 25 (32%) showed morphologic features suggestive of MSI. We detected MSI-H in 5 of 23 (22%) tumour blocks tested. Review with H&E staining correctly identified 80% of cases positive for MSI-H. The false-positive rate and positive predictive value on H&E review was 50%. The negative predictive value of histomorphologic H&E review was 94%. Three patients were available for and had mutational analysis of DNA mismatch repair genes; 2 were positive for mutations in keeping with Lynch syndrome and 1 had MLH1 alterations of uncertain significance. All 3 met the Amsterdam criteria for hereditary nonpolyposis CRC.

CONCLUSION

Thirteen percent of the population had mutations in keeping with Lynch syndrome. This prevalence is similar to that reported for white populations.

A comparison of models used to predict MLH1, MSH2 and MSH6 mutation carriers

BACKGROUND

MMRpro, prediction of mutations in MLH1 and MLH2 (PREMM(1,2)) and MMRpredict are models which were developed to predict the probability that an individual carries a Lynch syndrome-causing mutation. Each model utilizes data from personal and family histories of cancer. To date, no studies have compared these models in a cancer genetics clinic. The purpose of this study was to determine each model's ability to predict the probability of carrying a Lynch syndrome-causing mutation in individuals with a family history of colorectal cancer and to determine their clinical applicability.

METHODS

We obtained family pedigrees from 81 individuals who presented for Lynch syndrome testing due to a personal and/or family history of cancer. Data from each pedigree were entered into the models and analyzed using SPSS.

RESULTS

We found that MMRpredict, PREMM(1,2) and MMRpro showed similar performances with areas under the receiver-operating characteristic curve of 0.731, 0.765 and 0.732, respectively. MMRpro showed the least dispersion of mutation probability estimates with a P value of 0.205, compared with 0.034 for PREMM(1,2) and 0.001 for MMRpredict.

CONCLUSION

We found all three carried out well in a cancer genetics setting, with PREMM(1,2) giving slightly better estimates. There were some significant discrepancies between the models in cases where the proband had endometrial cancer.

Surgical Implications of Colorectal Cancer Genetics

The applications of genetics in colorectal cancer are not limited to identifying germ-line mutations in genetically predisposed individuals. Reports on the use of molecular genetic markers as prognostic factors and for assessing the response to therapy are common in the literature. As the primary caregiver in the majority of these cases, the surgeon needs a basic knowledge of colorectal genetics and their implications to the patient and the patient's family. This article discusses a practical approach for some of the issues likely to be encountered by the surgeon.

Inherited colorectal cancer syndromes

Colorectal cancer is one of the major causes of cancer deaths in both men and women. It is estimated that approximately 5% to 10% of patients with colorectal cancer have an inherited germline mutation that predisposes them to cancer. Clinically, hereditary colorectal cancer syndromes can be divided into those associated with colonic polyposis (familial adenomatous polyposis, attenuated familial adenomatous polyposis, and MYH-associated polyposis) and those not associated with colonic polyposis (hereditary nonpolyposis colon cancer). Treatment options for these patients include multiple aggressive screening regimens, chemopreventive medications, and prophylactic surgery. Selection of the appropriate management approach is best made using information obtained from the patient's clinical examination, the family medical history, and genetic evaluation. Compliance is improved when patients completely understand their disease and participate fully in the formulation of the treatment plan. Although not proved, it seems reasonable that this approach may prevent the poor outcomes so frequently associated with inherited cancer syndromes.

The clinical features of rectal cancers with high-frequency microsatellite instability (MSI-H) in Japanese males

Colorectal cancers with high-frequency microsatellite instability (MSI-H) are known to display striking differences in their clinical and pathological features compared to microsatellite stable (MSS) cancers. Previous studies revealed that MSI-H cancers are more likely to occur in women, irrespective of the higher incidence of colorectal cancer in men. In this study we investigated the gender-specific clinico-pathological features of MSI positive colorectal cancer in Japanese individuals. A series of 478 colorectal carcinomas were collected in an unbiased manner and analyzed for microsatellite instability status. Seven percent, 6% and 87% of tumors showed MSI-H, low-frequency microsatellite instability (MSI-L) and MSS, respectively. A comparison of gender indicated a statistical significance in terms of the distribution of the subsite and age of onset of MSI-H colorectal cancer. In general, MSI-H cancers prone to develop in the proximal colon however, we found that about 36% of MSI-H cancers in men developed in the rectum. These rectal cancers were more likely to have a mucinous component and multiple colorectal cancers including critical lesion. These findings should be useful to find MSI positive rectum cancer.

Clinical features and mismatch repair gene mutation screening in Chinese patients with hereditary nonpolyposis colorectal carcinoma

AIM: Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominantly-inherited cancer-susceptibility syndrome that confers an increased risk for colorectal cancer and a variety of other tumors at a young age. It has been associated with germline mutations in five mismatch repair (MMR) genes (hMSH2, hMLH1, hPMS1, hPMS2, and hMSH6/GTBP). The great majority of germline mutations were found in hMSH2 and hMLH1. The purpose of this study was to analyze the clinical features of Chinese HNPCC patients and to screen hMSH2 and hMLH1 gene mutations.

METHODS: Twenty-eight independent Chinese families were collected, of which 15 met Amsterdam criteria I and 13 met the Japanese clinical diagnosis criteria. The data were recorded including sex, site of colorectal cancer (CRC), age of diagnosis, history of synchronous and/or metachronous CRC, instance of extracolonic cancers, and histopathology of tumors. Peripheral blood samples were collected from all pedigrees after formal written consents were signed. PCR and denaturing high-performance liquid chromatography (DHPLC) were used to screen the coding regions of hMSH2 and hMLH1 genes. The samples showing abnormal DHPLC profiles were sequenced by a 377 DNA sequencer.

RESULTS: One hundred and seventy malignant neoplasms were found in one hundred and twenty-six patients (multiple cancer in twenty-three), including one hundred and twenty-seven CRCs, fifteen gastric, seven endometrial, and five esophageal cancers. Seventy-seven point eight percent of the patients had CRCs, sharing the features of early occurrence (average age of onset, 45.9 years) and of the right-sided predominance reported in the literature. In Chinese HNPCC patients, gastric cancer occurred more frequently, accounting for 11.9% of all cancers patients and ranking second in the spectrum of HNPCC predisposing cancers. Synchronous CRCs occurred less frequently, only accounting for 3.1% of the total CRCs. Twenty percent of the colorectal patients had metachronous CRCs within 10 years after operation. Eight hMSH2 or hMLH1 gene sequence variations were found in twelve families, including the first Mongolian kindred with a hMSH2 gene mutation.

CONCLUSION: HNPCC is characterized by an early-age onset, proximal predominance of CRC, multiple metachronous CRCs, and an excess of extra-colonic cancers. Frequent gastric cancer occurrence and less synchronous CRCs are the remarkable features in Chinese HNPCC patients. DHPLC is a powerful tool in hMSH2 and hMLH1 gene mutation screening. hMLH1 gene mutations, especially of the first nine exons, have been found more common than hMSH2 gene mutations in Chinese patients. Three of seven mutations have been found to be novel, and the germline G204X nonsense mutation in the third exon of hMSH2 has become the first MMR gene mutation found in Chinese Mongolian people.

Lynch syndrome: implications for the surgeon

Hereditary nonpolyposis colorectal cancer (HNPCC), or Lynch syndrome, is an autosomal dominant syndrome characterized by onset of colorectal cancer (CRC) at an early age, right-sided predominance, excess synchronous and metachronous colorectal neoplasms, and extracolonic neoplasms. It is the most common of the hereditary CRCs, so the practicing surgeon should expect to encounter patients with this disease. The diagnosis of HNPCC, which begins with a complete family history and a high index of suspicion by the clinician, has important implications in the management and surveillance of not only the affected individual but also for the individual's family. In this article, the diagnosis and management of Lynch syndrome will be reviewed, with emphasis on the implications for the surgeon.

Pathogenesis and clinical management of hereditary non-polyposis colorectal cancer

BACKGROUND

Hereditary non-polyposis colorectal cancer (HNPCC) is an inherited genetic condition associated with microsatellite instability; it accounts for around 5 per cent of all cases of colorectal cancer. This review examines recent data on management strategies for this condition.

METHODS

A Medline-based literature search was performed using the keywords 'HNPCC' and 'microsatellite instability'. Additional original papers were obtained from citations in articles identified by the initial search.

RESULTS AND CONCLUSION

The Amsterdam criteria identify patients in whom the presence of an inherited mutation should be investigated. Those with a mutation should be offered counselling and screening. The role of prophylactic surgery has been superseded by regular colonoscopy, which dramatically reduces the risk of colorectal cancer. Screening for extracolonic malignancy is also advocated, but the benefits are uncertain. Chemoprevention may be of value in lowering the incidence of bowel cancer in affected patients, but further studies are required.

Report of 16 kindreds and one kindred with hMLH1 germline mutation

AIM: To analyze the diagnosis and treatment of 16 hereditary nonpolyposis colorectal cancer (HNPCC) kindreds, and to report the first kindred with hMLH1 germline mutation in Mainland China.

METHODS: The diagnosis, treatment and follow-up study of 16 HNPCC kindreds were retrospectively reviewed. Data concerning site of the malignant tumor, age at the diagnosis, history of synchronous and/or metachronous cancer, and histopathology of tumors were recorded. All treatments had won formal consent. PCR and SSCP were used to screen the coding region of hMLH1 and hMSH2 genes. Variant bands were sequenced by a 377 DNA sequencer.

RESULTS: Among sixteen kindreds, sixty-eight patients had a mean age of 50.8 years, including twenty-one multiple cancer patients and forty-six colorectal cancer patients (metachronous colorectal cancers in sixteen). A total of one hundred and one malignant neoplasms were found in these sixty-eight patients, including 50 colonic, 17 rectal, 11 gastric, 7 endometrial, and 4 esophageal cancers. 39.5% colorectal patients had metachronous cancers within ten years who needed reoperations. A germline G265T nonsense mutation was found in the third exon of hMLH1, resulting in a stop codon and truncated protein. Three phenotypically normal family members were also found to carry the mutated gene.

CONCLUSION: HNPCC is a typical auto-dominant hereditary disease, the main characteristics include early onset and frequency of cancers; predominance of colorectal, especially right-sided colon cancers; frequency of multiple primary cancers (especially colorectal cancers). Segmental resection for colorectal cancers is not eligible for colorectal cancer patient in HNPCC kindreds. Intensive follow-up is essential for all patients and possible gene carriers. The first HNPCC kindred with hMLH1 gene germline mutation was identified in Mainland China, and three phenotypically normal family members were found to be carriers of the mutated gene. The G265T germline (nonsense) mutation in the third exon of hMLH1 found here had not been reported previously in the literature.

Molecular and genetic defects in colorectal tumorigenesis

Colorectal cancers, whether sporadic or hereditary, are caused by a defined set of molecular events. There are at least two different pathogenetic pathways for colorectal cancer: the chromosomal instability pathway and the microsatellite instability pathway; the two major inherited syndromes, familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC), are examples of these two mechanisms. These different pathways, however, converge on common pathological entities that have crucial functions in the regulation of normal crypt homeostasis. Preventive strategies aimed at reversing these changes, or therapeutic interventions targeting cell populations with these alterations, should be most efficacious. Genetic testing for inherited syndromes is now available and allows appropriate management of these disorders. Further insight into colorectal tumorigenesis pathways can lead to the development of useful prognostic indicators and target preventive and therapeutic strategies in the management of colorectal cancer.

Use of microsatellite analysis in young patients with colorectal cancer to identify those with hereditary nonpolyposis colorectal cancer

BACKGROUND AND OBJECTIVES

The frequency of microsatellite instability (MSI) in young patients with colorectal cancer was evaluated, including reexamination of the medical and family history of each patient, and interviews with the patients to determine any possible new occurrence of hereditary nonpolyposis colorectal cancer (HNPCC) in the patients themselves or their family members.

METHODS

Fifty-three young patients (younger than 40 years of age) with colorectal cancer were selected and investigated. DNA was extracted from paraffin sections and microsatellite analysis was performed.

RESULTS

The frequency of MSI among the young patients with colorectal cancer was 50.9%, which was significantly higher than the rate of 12-21% noted in older patients with colorectal cancer (P < 0.001). For the 24 young patients with colorectal cancer who did not have MSI, only one case of HNPCC kindred and two cases with a family history of cancer were identified. In contrast, among the 20 young patients with colorectal cancer who had MSI, five cases of HNPCC kindred, two cases with metachronous patients with colorectal cancer, and three cases with a family history of cancer were identified.

CONCLUSION

Our results suggest that a defect in the DNA mismatch repair system may play some role in carcinogenesis in young patients with colorectal cancer. Microsatellite analysis and subsequent interviews regarding medical and family history are useful tools for efficiently identifying possible cases of HNPCC among young patients with colorectal cancer.

Second primary neoplasms in 633,964 cancer patients in Sweden, 1958-1996

The Swedish Family-Cancer Database was used to analyze concordant (same site) and discordant (different site) second primary neoplasms in 633,964 cancer patients diagnosed from 1958 to 1996. Cases of second malignant neoplasms were extracted from the Database if the diagnosis date of the first and second cancer differed by at least 1 month. The expected numbers of cancers were obtained by applying site-, sex-, age-, period-, residence- and socioeconomic level-specific rates in the corresponding population in the Database to the appropriate person-years at risk. The standardized incidence ratio (SIRs) of a second cancer was taken to be the ratio of observed to expected numbers of second cancers. Of all cancers, 8.5% were subsequent neoplasms (8.4% for males and 8.7% for females). SIRs for both concordant and discordant subsequent cancer were elevated in patients with cancer of the upper aerodigestive tract, colon, nose, breast, other female genitals, testis, kidney, urinary, bladder, skin, nervous system, endocrine, bone, connective tissue, melanoma, lymphoma and leukemia. The risks at some concordant sites, such as nose, squamous cell skin, bone and connective tissue in both sexes, breast in males and upper aerodigestive tract and leukemia in females, were very high (>10). At discordant sites, SIRs were less than 2 but significantly increased after all but gastric and prostatic cancer. Compared with the general population, cancer patients were at a modestly increased risk for new primary cancer after cancers at many sites, calling for attention in treatment, management and prevention.

Rectal cancer in hereditary nonpolyposis colorectal cancer

BACKGROUND

Hereditary nonpolyposis colorectal cancer (HNPCC) accounts for approximately 2% to 5% of all colorectal cancers. Rectal cancer in HNPCC is not well characterized.

METHODS

A retrospective medical record review of HNPCC patients with colorectal cancer diagnosis from December 1948 to December 1999 was performed in an attempt to elucidate the natural history of rectal cancer in HNPCC. Group A consisted of patients diagnosed with rectal cancer as the index colorectal cancer. Group B consisted of patients diagnosed with rectal cancer as a metachronous colorectal cancer.

RESULTS

Twenty-five of 104 patients developed rectal cancer in our HNPCC registry. There were 18 patients in group A with a median age at diagnosis of rectal cancer of 48 years (range 24 to 79) and 7 patients in group B diagnosed at a median age of 58 years (range 45 to 68). Three of 18 patients (17%) in group A developed metachronous colon cancers at a median of 203 months (range 27 to 373) from the index rectal cancer. Rectal cancer in group B was diagnosed at a median 245 months (range 51 to 564) from the index colorectal cancer diagnosis.

CONCLUSIONS

Rectal cancer in HNPCC is not uncommon. The presentation of rectal carcinoma should not obviate the evaluation for HNPCC in suspected cases.

Microsatellite instability: application in hereditary non-polyposis colorectal cancer

Colorectal cancer (CRC) is a significant cause of mortality in Western populations. About 15% of CRC patients report a family history of the disease. Studies on individuals with a genetic predisposition to CRC have been responsible for significant advances in the understanding of this disease. Thus, although developments in molecular biology have been mainly restricted to a minority of individuals with a hereditary background, information obtained from this group may affect the diagnosis and therapy of sporadic CRCs as well. Deficiency in the DNA mismatch repair (MMR) system results in microsatellite instability (MSI). Individuals from hereditary non-polyposis colorectal cancer (HNPCC) kindreds with germline mutations in genes involved in MMR may benefit from clinical screening programs. The higher frequency of MSI in HNPCC than in sporadic tumours suggests that involvement of MMR genes in sporadic adenomas may be uncommon. Consequently

Gene-environment interaction in hereditary nonpolyposis colorectal cancer with implications for diagnosis and genetic testing

Hereditary nonpolyposis colorectal cancer (Lynch syndrome) is an autosomal dominant disease caused by mutations in the mismatch repair genes in particular in MLH1, MSH2 and MSH6. The disease is characterized by the development of colorectal, endometrial cancer and several other cancers. There is evidence that the clinical expression of the disease varies from one country to another. This variation might affect not only the application of criteria proposed to identify families but also clinical risk factors reported to predict the outcome of genetic testing. Data on site of the cancer, age at diagnosis and pathology were collected from 155 families with suspected HNPCC known at the Korean and Dutch HNPCC registries. DGGE, SSCP and DNA-sequencing were performed to identify MSH2, MLH1 and MSH6 mutations. A total of 33 Korean and 42 Dutch families met the clinical criteria for HNPCC. Germline mutations in the MMR-genes were found in 23 Korean and 24 Dutch families. In families that met the Amsterdam criteria, and also in those associated with MLH1 mutations, more cancers of the stomach and pancreas were observed in the Korean families than in the Dutch HNPCC families; in relative terms, the incidence of cancers of the endometrium in the Korean families was lower. Multivariate analysis showed that an early age at diagnosis, and the occurrence of pancreatic cancer were independent predictive factors of germline mutations in MLH1, MSH2 and MSH6 in the Korean subset of families.

Suspected hereditary nonpolyposis colorectal cancer: International Collaborative Group on Hereditary Non-Polyposis Colorectal Cancer (ICG-HNPCC) criteria and results of genetic diagnosis

PURPOSE

The aim of this study was to determine the frequency of mutations in the mismatch repair genes in families suspected of having hereditary nonpolyposis colorectal cancer.

METHODS

We devised two criteria for families suspected of having hereditary nonpolyposis colorectal cancer (Criteria I and II). Criteria I consist of at least two first-degree relatives affected with colorectal cancer with at least one of the following: development of multiple colorectal tumors including adenomatous polyp, at least one colorectal cancer case diagnosed before the age of 50, and occurrence of a hereditary nonpolyposis colorectal cancer extracolonic cancer (endometrium, urinary tract, small intestine, stomach, hepatobiliary system, or ovary) in family members. Criteria II consist of one colorectal cancer patient with at least one of the following: early age of onset (<40 years); endometrial, urinary tract, or small intestine cancer in the index patient or a sibling (one aged <50 years); and two siblings with other integral hereditary nonpolyposis colorectal cancer extracolonic cancers (one aged <50 years). A questionnaire was mailed to members of the International Collaborative Group on Hereditary Non-Polyposis Colorectal Cancer to determine the mutation detection rate in mismatch repair genes from the families fulfilling these criteria. For comparison the mutation detection rate for families fulfilling the Amsterdam hereditary nonpolyposis colorectal cancer criteria in each institution was also obtained.

RESULTS

Data were obtained from eight different institutions (in 7 different countries). In a total of 123 patients from 123 families (67 families fulfilling Criteria I and 56 families fulfilling Criteria II), genetic testing for germline mismatch repair gene variants was performed. Germline mutations of the hMLH1 or hMSH2 genes were identified in 24 families (20 percent). Of these, the mutation detection rate for families fulfilling Criteria I was 28 percent (19/67). The mutation detection rate for families fulfilling Criteria II was 9 percent (5/56). In these eight institutions, the overall mutation detection rate for families fulfilling the Amsterdam hereditary nonpolyposis colorectal cancer criteria was 50 percent (77/154).

CONCLUSION

The Criteria I for suspected hereditary nonpolyposis colorectal cancer have the advantages that they can be applied to nuclear families and they can include extracolonic cancers. The results of this study suggest that families fulfilling Criteria I should be offered genetic testing. The relatively low mutation detection rate in those families fulfilling Criteria II suggests that, using current techniques, genetic testing in these families is not practical.

Varying features of early age-of-onset "sporadic" and hereditary nonpolyposis colorectal cancer patients

PURPOSE

Although the criteria for clinical diagnosis of hereditary nonpolyposis colorectal cancer are not fully agreed on, young age seems to be a common trait. The purpose of this study is to identify clinicopathologic features of hereditary nonpolyposis colorectal cancer in early age-of-onset colorectal cancer patients stratified as a function of family cancer history.

METHODS

Two hundred thirty consecutive colorectal cancer patients 40 years or older at time of diagnosis were registered into an ongoing database during a ten-year period. Accurate family history was obtained via medical records, telephone calls, and questionnaires on 146 patients. According to extent of family history of cancer, patients were stratified into seven groups: 1) fulfilling Amsterdam criteria, 2) fulfilling less strict criteria, 3) having at least one first-degree relative with colorectal cancer, 4) having at least one distant relative with colorectal cancer, 5) having at least one first-degree relative with any cancer, 6) having at least one distant relative with any cancer, 7) having no family history of cancer.

RESULTS

Twenty-two of 146 patients fulfilled Amsterdam and less strict hereditary nonpolyposis colorectal cancer criteria (15 percent). These hereditary nonpolyposis colorectal cancer patients were significantly younger (31 vs. 35 years; P = 0.0003) and had more metachronous colorectal cancer (27 percent vs. 2 percent; P = 0.007) and less colorectal cancer with nodal or metastatic spread than the non-hereditary nonpolyposis colorectal cancer patients (35 percent vs. 65 percent; P = 0.01).

CONCLUSION

Precise familial cancer assessment in early age-of-onset colorectal cancer increases the yield of hereditary nonpolyposis colorectal cancer diagnosis. Because of the frequent development of metachronous colorectal cancer and favorable prognosis, extensive rather than segmental surgery should be considered in early age-of-onset colorectal cancer patients belonging to hereditary nonpolyposis colorectal cancer families.