Population-based risk assessment for other cancers in relatives of hereditary prostate cancer (HPC) cases

Skin Melanoma and Subsequent Risk of Prostate Cancer: A Lithuanian Cancer Registry Study

Emerging data indicates that melanoma may be linked to prostate cancer. We evaluated if the incidence of melanoma was associated with subsequent risk of prostate cancer (PC). We extracted data from the Lithuanian cancer registry from 1993 to 2012. We calculated the standardized incidence ratios (SIRs) for PC as a ratio of observed number of cancer cases in people with previous melanoma diagnosis to the expected number of cancer cases in the underlying general population. Therein, 95% confidence intervals for the SIRs were estimated assuming the number of observed cancer cases follows the Poisson distribution. Overall, 65 PCs were observed versus 52.5 expected (SIR 1.24; 95% CI: 0.97–1.58) within a period of 24 years. A significantly increased risk of PC was found in patients with melanoma diagnosis over 70 years (SIR 1.62; 95% CI: 1.11–2.39) and in two periods of diagnosis (SIRs 1.76 and 1.62 in 1993–1997 and 2009–2012, respectively). A significantly increased risk was also found five to nine years after melanoma diagnosis (SIR 1.58; 95% CI: 1.05–2.38). Further studies are needed to evaluate the relationship between melanoma and subsequent risk of prostate cancer.

The impact of prior malignancies on second malignancies and survival in MM patients: a population-based study

In the present study, we aimed to evaluate 2 hypotheses. First, we hypothesize that prior malignancy is a proxy for genetic susceptibility that could be a risk factor for subsequent malignancy development in multiple myeloma (MM) patients. Second, we hypothesize that survival after MM is influenced by a prior malignancy. All patients diagnosed with MM from 1 January 1973 to 31 December 2010 were identified from the Swedish Cancer Register. Cox regression model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) where prior malignancy was compared in MM patients who developed a subsequent malignancy and MM patients who did not. In another Cox regression model, survival was compared in MM patients with and without a prior malignancy diagnosis. A total of 19 791 patients were diagnosed with MM. Patients with a prior malignancy diagnosis had a significantly increased risk of developing a subsequent malignancy compared with MM patients without (HR 1.42, 95% CI 1.23-1.65, P < .001). MM patients with a prior malignancy diagnosis had a significant 1.21-fold increased risk of death (95% CI 1.115-1.26, P < .001) compared with MM patients without. MM patients with 2 or more prior malignancy diagnoses had a 1.34-fold increased risk of death (95% CI 1.19-1.52, P < .001). In this large population-based study, we report that prior malignancy increases the risk of subsequent malignancy development in MM patients. Furthermore, we found that prior malignancy negatively impacts survival and that >1 prior malignancy reduces survival even further.

Familial Risk of Biliary Tract Cancers: A Population-Based Study in Utah

BACKGROUND AND OBJECTIVES

Biliary tract cancers (BTC) including, cholangiocarcinoma (CC) and gallbladder cancer (GBC), are rare and highly fatal malignancies. The etiology and inherited susceptibility of both malignancies are poorly understood. We quantified the risk of BTC in first-degree (FDR), second-degree (SDR), and first cousin (FC) relatives of individuals with BTC, stratified by tumor subsite.

METHODS

BTC diagnosed between 1980 and 2011 were identified from the Utah Cancer Registry and linked to pedigrees from the Utah Population Database. Age- and gender-matched BTC-free controls were selected to form the comparison group for determining BTC risk in relatives using Cox regression analysis.

RESULTS

Of the 1302 index patients diagnosed with BTC, 550 (42.2 %) were located in the gallbladder and 752 (57.8 %) were cholangiocarcinomas. There was no elevated risk of BTC (all subsites combined) in FDRs (HR 0.94, 95 % CI 0.29-3.0), SDRs (HR 0.25, 95 % CI 0.06-1.03), and FCs (HR 0.96, 95 % CI 0.61-1.51) of BTC cases compared to cancer-free controls. Similarly, no increased familial risk of GBC or CC was found in relatives of BTC patients stratified by tumor subsite compared to relatives of controls.

CONCLUSIONS

Relatives of BTC patients are not at an increased risk of GBC or CC in a statewide population. This suggests that biliary tract cancer risk is not associated with a familial predisposition and may be mitigated more strongly by environmental modifiers.

The aggregation of early-onset melanoma in young Western Australian families

BACKGROUND

Few studies have examined the familial aggregation of melanoma or its co-aggregation with other cancers using whole-population based designs. This study aimed to investigate aggregation patterns in young Western Australian families, using population-based linked health data to identify individuals born in Western Australia between 1974 and 2007, their known relatives, and all incident cancer diagnoses within the resulting 1,506,961 individuals.

METHODS

Cox proportional hazards regression models were used to compare the risk of melanoma for first-degree relatives of melanoma cases to that for first-degree relatives of controls, with bootstrapping used to account for correlations within families. The risk of (i) developing melanoma based on the number of first-degree relatives with other cancers, and (ii) developing non-melanoma cancers based on the number of first-degree relatives diagnosed with melanoma was also investigated.

RESULTS

First-degree relatives of melanoma cases had a significantly greater incidence of melanoma than first-degree relatives of individuals not affected with melanoma (Hazard Ratio (HR)=3.58, 95% bootstrap confidence interval (CI): 2.43-5.43). Sensitivity analyses produced a higher hazard ratio estimate when restricted to melanoma cases diagnosed before 40 years of age (HR=3.77, bootstrap 95% CI: 2.49-6.39) and a lower estimate when only later-onset cases (>40 years) were considered (HR=2.45, bootstrap 95% CI: 1.23-4.82). No significant evidence was found for co-aggregation between melanoma and any other cancers.

CONCLUSIONS

Results indicated a strong familial basis of melanoma, with the higher than expected hazard ratio observed likely to reflect early-age at onset cases in this young cohort, supported by the results of the sensitivity analyses. Exploratory analyses suggested that the determinants of melanoma causing the observed aggregation within families may be independent of other malignancies, although these analyses were limited by the young age of the sample. Determining familial aggregation patterns will provide valuable knowledge regarding improved clinical risk prediction and the underlying biological mechanisms of melanoma and other cancers.

A population-based analysis of clustering identifies a strong genetic contribution to lethal prostate cancer

BACKGROUND

Prostate cancer is a common and often deadly cancer. Decades of study have yet to identify genes that explain much familial prostate cancer. Traditional linkage analysis of pedigrees has yielded results that are rarely validated. We hypothesize that there are rare segregating variants responsible for high-risk prostate cancer pedigrees, but recognize that within-pedigree heterogeneity is responsible for significant noise that overwhelms signal. Here we introduce a method to identify homogeneous subsets of prostate cancer, based on cancer characteristics, which show the best evidence for an inherited contribution.

METHODS

We have modified an existing method, the Genealogical Index of Familiality (GIF) used to show evidence for significant familial clustering. The modification allows a test for excess familial clustering of a subset of prostate cancer cases when compared to all prostate cancer cases.

RESULTS

Consideration of the familial clustering of eight clinical subsets of prostate cancer cases compared to the expected familial clustering of all prostate cancer cases identified three subsets of prostate cancer cases with evidence for familial clustering significantly in excess of expected. These subsets include prostate cancer cases diagnosed before age 50 years, prostate cancer cases with body mass index (BMI) greater than or equal to 30, and prostate cancer cases for whom prostate cancer contributed to death.

CONCLUSIONS

This analysis identified several subsets of prostate cancer cases that cluster significantly more than expected when compared to all prostate cancer familial clustering. A focus on high-risk prostate cancer cases or pedigrees with these characteristics will reduce noise and could allow identification of the rare predisposition genes or variants responsible.

Multiple myeloma and its therapies: to what extent do they contribute to the increased incidence of second malignant neoplasms?

BACKGROUND

The high risk of another cancer once one has been diagnosed is well known. Furthermore, a clear association exists between the use of some cytotoxic agents and chemotherapy-induced malignancies.

METHODS

This review is set to explore the relationship between multiple myeloma, its modern therapies and the development of second cancers due to various genetic, immune, and environmental (including iatrogenic) factors. Most relevant publications were identified through the PubMed database and by reviewing the drug information released by the US Federal Drug Administration.

FINDINGS

Our comprehensive analysis identified several retrospective population studies, cohort group analyses and a number of case reports linking myeloma with other cancers in the world literature. A majority of these studies suggest that incidence of second solid and hematologic malignancies is significantly increased in patients with multiple myeloma and its precursor lesion, monoclonal gammopathy of unknown significance. In addition, incidence of second malignancies has been found increased in the family members of these individuals, especially in their first-degree relatives.

CONCLUSIONS

Analysis of the existing literature cohorts does not discriminate between the burden of second cancers in treated myeloma patients as opposed to the patients followed with the wait-and-watch approach. Notably, the rate of second malignant neoplasms in multiple myeloma may be further increased by certain myeloma therapies. These cancers include, for the most part, hematologic malignancies such as acute leukemias and certain lymphomas. While there is no question about the role of alkylating agents and topoisomerase II inhibitors in this regard, further research is necessary to determine whether the excess of second cancers represents a direct consequence of lenalidomide use.

A comprehensive survey of cancer risks in extended families

PURPOSE

Cancer is familial; yet known cancer predisposition genes, as well as recognized environmental factors, explain only a small percentage of familial cancer clusters. This population-based description of cancer clustering describes patterns of cancer coaggregation suggestive of a genetic predisposition.

METHODS

Using a computerized genealogy of Utah families linked to a statewide cancer registry, we estimated the relative risks for 36 different cancer sites in first-, second-, and third-degree relatives of cancer cases, for each cancer site individually, and between cancer sites. We estimated the sex- and birth-year-specific rates for cancer using 1 million individuals in the resource. We applied these rates to groups of cases or relatives and compared the observed and expected numbers of cancers to estimate relative risks.

RESULTS

Many cancer sites show significantly elevated relative risks among distant relatives for cancer of the same site, strongly supporting a heritable contribution. Multiple combinations of cancer sites were observed among first-, second-, and third-degree relatives, suggesting the existence of heritable syndromes involving more than one cancer site.

CONCLUSION

This complete description of coaggregation of cancer by site in a well-defined population provides a set of observations supporting heritable cancer predispositions and may support the existence of genetic factors for many different cancers.

Risk for incident and fatal prostate cancer in men with a family history of any incident and fatal cancer

BACKGROUND

Familial clustering of incident prostate cancer and some cancers at other discordant sites has been reported. Less is known about familial clustering of fatal prostate cancer with any fatal discordant cancers. Estimates on familial aggregation based on mortality are free from bias of overdiagnosis.

PATIENTS AND METHODS

We used the nationwide Swedish Family-Cancer Database to calculate standardized incidence ratios (SIRs) for incident prostate cancer for relatives of patients with any common cancer and standardized mortality ratios (SMRs) for death in prostate cancer for relatives of individuals who died from cancer. Similar risks were determined for any common cancer when relatives were affected by prostate cancer.

RESULTS

We observed familial aggregation of incident and fatal prostate cancers. Familial clustering (SIRs increased) of prostate cancer and of cancers at discordant sites was found for breast, ovarian, and kidney cancers and melanoma. Also, fatal prostate cancer clustered with these and cervical cancers (SMRs increased).

CONCLUSIONS

Our findings demonstrate that familial aggregation of prostate and breast cancers are not due to shared screening habits. The data on the association of cancers at discordant sites might be useful for clinical counseling and for mechanistic studies searching explanations to the familial clustering between discordant cancers.

[Ten years national research project "familial prostate cancer": problems in identifying risk families]

BACKGROUND

The German national research project"familial prostate cancer" has been recruiting prostate cancer patients nationwide since 1999. In 2009, a comprehensive data analysis of the 25,065 families recruited was performed. Of these, 77.4% were identified as sporadic, 20.0% as familial and 2.6% as hereditary cases of prostate cancer. However, obtaining comprehensive, validated information about all relatives often fails.

RESULTS

The high average age of the patients, the lower life expectancy in further generations and the low number of first-degree male relatives hampers the classification of sporadic, familial and hereditary cases. Consequently we describe here that in our database the identification of 100 hereditary cases requires a recruitment of more than 5,000 patients with their families. For 100 sporadic patients with 2 first-degree male relatives without a case history 1,250 patients are needed.

Prostate cancer risk alleles and their associations with other malignancies

OBJECTIVE

To determine whether certain risk alleles are responsible for the relationship between prostate cancer (CaP) and other malignancies. CaP has been associated with other common malignancies. Recently, numerous single nucleotide polymorphisms (SNPs) have been associated with CaP susceptibility.

METHODS

We genotyped 1121 patients with CaP for 36 risk alleles known to be significantly associated with CaP susceptibility and determined their relationships to other malignancies in CaP probands and their first-degree relatives.

RESULTS

The most common other malignancies in the CaP probands were nonmelanoma skin cancer (13.6%), leukemia (7.3%), melanoma (3.9%), non-Hodgkin's lymphoma (0.7%), colorectal cancer (0.6%), and multiple myeloma (0.3%). Among the probands, a significantly increased frequency of leukemia was found in the carriers of SNP rs2736098 (5p15, P = .03) and melanoma in the carriers of either SNP rs1512268 (8p21, P = .006) or SNP rs5759167 (22q13, P = .02). Multiple myeloma was more common in carriers of SNP rs9364554 (6q25, P = .02). The probands who were carriers of SNP rs16901979 (8q24) were significantly more likely to report a family history of melanoma (P = .03), and the probands with a family history of multiple myeloma and non-Hodgkin's disease were significantly more likely to be carriers of SNP rs12621278 (2q31, P = .04) and rs6465657 (7q21, P = .02), respectively.

CONCLUSION

Certain alleles associated with CaP susceptibility might be associated with an increased or a decreased risk of other malignancies in CaP probands and their first-degree relatives. Additional studies are warranted to examine the underlying mechanisms of these SNPs in CaP and other malignancies.

Complex genotype sarcomas display familial inheritance independent of known cancer predisposition syndromes

BACKGROUND

The low incidence of sarcomas in the general population makes heritable contribution to disease risk difficult to discern beyond highly penetrant Mendelian syndromes.

METHODS

The Utah Cancer Registry (UCR) and Utah Population Database were interrogated for sarcoma diagnostic codes grouped by genetic type, either complex genotype/karyotype sarcoma or balanced translocation-associated sarcoma. The genealogic index of familiality (GIF) was calculated and relative risks (RR) of disease estimated for first-, second-, and third-degree relatives of sarcoma probands. Cancer patterns in pedigrees of sarcoma probands were examined to rule out known hereditary cancer syndromes.

RESULTS

A total of 229 balanced translocation type and 1,161 complex genotype type sarcomas with at least three generations of ancestral genealogy data were identified in the UCR. There was no evidence for excess relatedness for the balanced translocation group by using the GIF test (P = 0.657) and no significantly elevated RRs. In the complex genotype group, we observed significantly elevated GIF (P = 0.03). Modest RRs corroborated the GIF analysis, in which excess relatedness existed in distant relationships. No recognized cancer syndromes were identified among high-risk pedigrees.

DISCUSSION

We identified strong familiality among complex genotype sarcomas, independent from known cancer predisposition syndromes. In the absence of significantly elevated RRs for close relatives, the high GIF argues for a strong genetic-rather than environmental-component to complex genotype sarcoma risk. We observed no significant familial risk of developing balanced translocation-associated sarcomas, but the sample was small.

IMPACT

There exists yet to be deciphered heritable risk for developing complex genotype sarcomas.

Genome-wide linkage analyses of hereditary prostate cancer families with colon cancer provide further evidence for a susceptibility locus on 15q11-q14

The search for susceptibility loci in hereditary prostate cancer (HPC) is challenging because of locus and disease heterogeneity. One approach to reduce disease heterogeneity is to stratify families on the basis of the occurrence of multiple cancer types. This method may increase the power for detecting susceptibility loci, including those with pleiotropic effects. We have completed a genome-wide SNP linkage analysis of 96 HPC families, each of which has one or more first-degree relatives with colon cancer (CCa), and further analyzed the subset of families with two or more CCa cases (n = 27). When only a prostate cancer (PCa) phenotype was considered to be affected, we observed suggestive evidence for linkage (LOD ≥1.86) at 15q14, 18q21 and 19q13 in all families, and at 1p32 and 15q11-q14 in families with two or more CCa cases. When both the PCa and CCa phenotypes were considered affected, suggestive evidence for linkage was observed at 11q25, 15q14 and 18q21 in all families, and at 1q31, 11q14 and 15q11-14 in families with two or more CCa cases. The strongest linkage signal was identified at 15q14 when both PCa and CCa phenotypes were considered to be affected in families with two or more CCa cases (recessive HLOD = 3.88). These results provide further support for the presence of HPC susceptibility loci on chromosomes 11q14, 15q11-q14 and 19q13 and highlight loci at 1q31, 11q, 15q11-14 and 18q21 as having possible pleiotropic effects. This study shows the benefit of using a comprehensive family cancer history to create more genetically homogenous subsets of HPC families for linkage analyses.

A genealogical assessment of heritable predisposition to asthma mortality

RATIONALE

Asthma is a multifactorial disease; genetic factors have been suggested but have not been well defined.

OBJECTIVES

This study examined evidence for a heritable component to asthma mortality using a unique data resource consisting of Utah death certificates linked to a genealogy of Utah.

METHODS

Cases were defined as individuals whose death certificate listed asthma as a cause of death in a registry of all Utah deaths since 1904 (n = 1,553). The genealogical index of familiality analysis was used to compare the average relatedness of asthma deaths to the expected relatedness in the Utah population. Relative risks for asthma death in relatives of individuals who died of asthma are provided for close and distant relatives.

MEASUREMENTS AND MAIN RESULTS

The genealogical index of familiality identified a significantly higher average relatedness in cases (P < 0.001), even when close relationships were ignored. In addition, a significantly increased risk of dying of asthma was observed in first-degree relatives of cases (relative risk = 1.69, P < 0.001) and in second-degree relatives of cases (relative risk = 1.34, P = 0.003).

CONCLUSIONS

These results support a heritable contribution to asthma mortality.

Suggestive genetic linkage to chromosome 11p11.2-q12.2 in hereditary prostate cancer families with primary kidney cancer

BACKGROUND

The Seattle-based PROGRESS study was started in 1995 to ascertain hereditary prostate cancer (HPC) families for studies of genetic susceptibility. Subsequent studies by several research groups, including our own, suggest that HPC is a genetically heterogeneous disease. To be successful in mapping loci for such a complex disease, one must consider ways of grouping families into subsets that likely share the same genetic origin. Towards that end, we analyzed a genome-wide scan of HPC families with primary kidney cancer.

METHODS

An 8.1 cM genome-wide scan including 441 microsatellite markers was analyzed by both parametric and non-parametric linkage approaches in fifteen HPC families with the co-occurrence of kidney cancer.

RESULTS

There was no evidence for significant linkage in the initial findings. However, two regions of suggestive linkage were observed at 11q12 and 4q21, with HLOD scores of 2.59 and 2.10, respectively. The primary result on chromosome 11 was strengthened after excluding two families with members who had rare transitional cell carcinoma (TCC). Specifically, we observed a non-parametric Kong and Cox P-value of 0.004 for marker D11S1290 at 11p11.2. The 8 cM region between 11p11.2 and 11q12.2 was refined by the addition of 16 new markers. The subset of HPC families with a median age of diagnosis >65 years demonstrated the strongest evidence for linkage, with an HLOD = 2.50. The P-values associated with non-parametric analysis ranged from 0.004 to 0.05 across five contiguous markers.

CONCLUSIONS

Analysis of HPC families with members diagnosed with primary renal cell carcinoma demonstrates suggestive linkage to chromosome 11p11.2-q12.2.

Genome-wide linkage analysis for aggressive prostate cancer in Utah high-risk pedigrees

BACKGROUND

It has been proposed that studying alternative phenotypes, such as tumor aggressiveness, may be a solution for overcoming the apparent heterogeneity that has hindered the identification of prostate cancer (PC) genes. We present the results of a genome-scan for predisposition to aggressive PC using the Utah high-risk pedigree resource.

METHODS

We identified 259 subjects with aggressive PC in 57 extended and nuclear families. Parametric and non-parametric multipoint linkage statistics were calculated for a genome-wide set of 401 microsatellite markers using the MCLINK software package. Stratification analyses by the number of affected subjects per pedigree (<5, >or=5) and the average age at diagnosis of affected subjects (<70 years, >or=70 years) were also performed.

RESULTS

No significant results were observed at the genome-wide level, but suggestive evidence for linkage was observed on chromosomes 9q (HLOD = 2.04) and 14q (HLOD = 2.08); several pedigrees showed individual evidence for linkage at each locus (LOD > 0.58). The subset of pedigrees with earlier age at onset demonstrated nominal linkage evidence on chromosomes 3q (HLOD = 1.79), 8q (HLOD = 1.67), and 20q (HLOD=1.82). The late-onset subset showed suggestive linkage on chromosome 6p (HLOD = 2.37) and the subset of pedigrees with fewer than five affected subjects showed suggestive linkage on chromosome 10p (HLOD = 1.99).

CONCLUSIONS

Linkage evidence observed on chromosomes 6p, 8q, and 20q support previously reported PC aggressiveness loci. While these results are encouraging, further research is necessary to identify the gene or genes responsible for PC aggressiveness and surmount the overarching problem of PC heterogeneity.

Utah family-based analysis: past, present and future

A unique genealogical resource linked to phenotype data was created in Utah over 30 years ago. Here we review the history and content of this resource. In addition, we review three current methodologies used in conjunction with this resource to define the heritable contribution to phenotypes and to identify predisposition genes responsible for these phenotypes. Example analyses and high-risk pedigrees are presented. Finally we briefly review ways this resource, or others like it, may expand in future.

Population-Based Assessment of Non-Melanoma Cancer Risk in Relatives of Cutaneous Melanoma Probands

Using the unique Utah Population Database, which links Utah genealogical data with Utah cancer data, we examined risks for other cancers among relatives of 4,079 melanoma cases. Age- and sex-specific rates for 35 different cancer sites were calculated, and used to estimate relative risks among relatives. In addition to the well-recognized risk for melanoma among first-degree relatives, we found significantly increased risks for prostate, breast, and colon cancers, non-Hodgkin's lymphoma, and multiple myeloma, ranging from 32 to 72% increased risk. Among second-degree relatives, in addition to increased risk for melanoma, we identified significantly increased risks for prostate cancer and multiple myeloma (27 and 53% increase, respectively). Among first-degree relatives of melanoma cases diagnosed before the age of 40 years, we found significantly elevated risks for cutaneous melanoma (380% increase) and prostate cancer (83% increase). Significantly increased risks for prostate cancer and multiple myeloma in both first- and second-degree relatives of melanoma cases are suggestive of heritable cancer syndromes. The increased risks for five additional cancer types in first-degree relatives of melanoma cases suggest that individuals with a family history of melanoma should strictly adhere to recommended screenings for all cancers.

A genome-wide scan for naevus count: linkage to CDKN2A and to other chromosome regions

High numbers of melanocytic naevi (moles), and mutations in the p16 gene (CDKN2A), are two strong risk factors for cutaneous malignant melanoma. We have previously reported linkage of mole count to the CDKN2A locus. Here, we report genome-wide scans for mole counts (differentiated into flat, raised and atypical subtypes) with a total of 796 microsatellite markers for 424 families with 1024 twins and siblings, plus genotypes for 690 parents. Inclusion of 221 pairs of MZ twins enabled separation of shared environmental and polygenic influences, so placing an upper limit to estimates of QTL variance. Maximum likelihood multipoint variance component methods were used to assess linkage of naevus count. Sex, age, body surface area, skin colour, hair colour, sunburn and facial freckles were included as covariates. Peak linkage of flat mole count was to regions on chromosomes 2, 9, 8 and 17 with lod scores 2.95, 2.95, 2.50 and 2.15, respectively. The support for linkage to the CDKN2A gene region (9p21) increased to 3.42 when additional fine mapping markers were added. For raised mole count, there was suggestive evidence of linkage in our sample to chromosome 16 (lod=1.87), and for atypical mole count on chromosomes 1, 6 and X with lod scores of 2.20, 2.00 and 2.00, respectively. The multivariate linkage peaks generally match those from individual trait analyses, with the exception of a new peak on chromosome 4 (point-wise empirical P-value=0.001). We replicate our earlier finding of linkage to CDKN2A and discovering linkage to several novel regions that may also influence risk of the development of malignant melanoma.

Extracolonic cancers associated with hereditary nonpolyposis colorectal cancer in the Utah Population Database

BACKGROUND

The data describing the extracolonic cancers associated with hereditary nonpolyposis colorectal cancer (HNPCC) are variable.

METHODS

We ascertained all Amsterdam I criteria-positive pedigrees (N = 18) in the Utah Population Database (UPDB). We identified the extracolonic cancers in the colorectal cancer cases (N = 65) in these pedigrees, and in their first- (N = 509) and second-degree (N = 1,611) relatives. Standardized morbidity ratios were estimated by comparing the observed rates of extracolonic cancer in defined sets of relatives of probands with population expected rates estimated internally from the UPDB.

RESULTS

The extracolonic cancers observed in significant excess in the 65 Amsterdam I criteria-positive colorectal cancer (CRC) cases in the UPDB were uterine (N = 3, p = 0.003), lip (N = 2, p = 0.007), stomach (N = 2, p = 0.009), female genitalia (N = 1, p = 0.004) and larynx (N = 1, p = 0.05). Extracolonic cancers observed in significant excess in the 509 first-degree relatives of the 65 colorectal cancer (CRC) cases in these Amsterdam I criteria pedigrees included: thyroid (N = 5, p = 0.0002) and prostate (N = 19, p = 0.002). Thyroid cancer (N = 6, p = 0.003) was found in significant excess in the second-degree relatives of the Amsterdam I criteria-positive CRC cases.

CONCLUSIONS

In this population-based examination of the extracolonic cancers at excess in classic HNPCC pedigrees (selected by Amsterdam I criteria) we not only observed many of the same cancers previously reported to be associated with HNPCC in both CRC probands and their relatives, but also identified several previously unreported associations. Although our sample size is small, this study is population based, lacks ascertainment and recall bias, and benefits from uniform, consistent diagnoses of all cancers in a statewide registry.