Familial prostate cancer from the family-cancer database

Population genealogy resource shows evidence of familial clustering for Alzheimer disease

OBJECTIVE

To show the potential of a resource consisting of a genealogy of the US record linked to National Veterans Health Administration (VHA) patient data for investigation of the genetic contribution to health-related phenotypes, we present an analysis of familial clustering of VHA patients diagnosed with Alzheimer disease (AD).

METHODS

Patients with AD were identified by the International Classification of Diseases code. The Genealogical Index of Familiality method was used to compare the average relatedness of VHA patients with AD with expected relatedness. Relative risks for AD were estimated in first- to fifth- degree relatives of patients with AD using population rates for AD.

RESULTS

Evidence for significant excess relatedness and significantly elevated risks for AD in relatives was observed; multiple pedigrees with a significant excess of VHA patients with AD were identified.

CONCLUSIONS

This analysis of AD shows the nascent power of the US Veterans Genealogy Resource, in early stages, to provide evidence for familial clustering of multiple phenotypes, and shows the utility of this VHA genealogic resource for future genetic studies.

An epidemiological reappraisal of the familial aggregation of prostate cancer: a meta-analysis

Studies on familial aggregation of cancer may suggest an overall contribution of inherited genes or a shared environment in the development of malignant disease. We performed a meta-analysis on familial clustering of prostate cancer. Out of 74 studies reporting data on familial aggregation of prostate cancer in unselected populations retrieved by a Pubmed search and browsing references, 33 independent studies meeting the inclusion criteria were used in the analysis performed with the random effects model. The pooled rate ratio (RR) for first-degree family history, i.e. affected father or brother, is 2.48 (95% confidence interval: 2.25-2.74). The incidence rate for men who have a brother who got prostate cancer increases 3.14 times (CI:2.37-4.15), and for those with affected father 2.35 times (CI:2.02-2.72). The pooled estimate of RR for two or more affected first-degree family members relative to no history in father and in brother is 4.39 (CI:2.61-7.39). First-degree family history appears to increase the incidence rate of prostate cancer more in men under 65 (RR:2.87, CI:2.21-3.74), than in men aged 65 and older (RR:1.92, CI:1.49-2.47), p for interaction = 0.002. The attributable fraction among those having an affected first-degree relative equals to 59.7% (CI:55.6-63.5%) for men at all ages, 65.2% (CI:57.7-71.4%) for men younger than 65 and 47.9% (CI:37.1-56.8%) for men aged 65 or older. For those with a family history in 2 or more first-degree family members 77.2% (CI:65.4-85.0%) of prostate cancer incidence can be attributed to the familial clustering. Our combined estimates show strong familial clustering and a significant effect-modification by age meaning that familial aggregation was associated with earlier disease onset (before age 65).

Risk factors for prostate cancer in men aged less than 60 years: a case-control study from Italy

OBJECTIVES

To analyze the relationship between selected risk factors and prostate cancer risk in men younger than 60 years, using data from a large, multicenter, case-control study conducted in Italy.

METHODS

Cases were 219 patients, aged 45 to 59 years, with histologically confirmed prostate cancer, and controls were 431 men of the same age group, admitted in hospital for acute, non-neoplastic diseases.

RESULTS

A family history of prostate cancer (odds ratio [OR] = 5.5), brain cancer (OR = 3.7), and leukemia (OR = 6.2) were associated with prostate cancer risk. A significantly increased risk was found for high education level (OR = 3.3 for 12 or more years versus less than 7 years) and a decreased risk for physical activity (OR = 0.5 for active versus inactive). Coffee consumption was directly associated with risk of prostate cancer (OR = 1.9 for the third versus the first tertile). Bread consumption was directly related (OR = 1.6) and consumption of raw and total vegetables inversely related (OR = 0.6) to prostate cancer risk, although these associations were of borderline significance. No association emerged with marital status, body mass index, history of diabetes, alcohol drinking, and other considered foods.

CONCLUSIONS

This study confirms that some recognized risk factors, including family history of prostate cancer, high level of education, and low physical activity, are associated with prostate cancer risk in middle-aged men.

Increased cancer risk for individuals with a family history of prostate cancer, colorectal cancer, and melanoma and their associated screening recommendations and practices

Prostate cancer, colorectal cancer, and melanoma are three malignancies that appear to have strong genetic components that can confer additional risk to family members. Screening tools, albeit controversial, are widely available to potentially aide in early diagnosis. Family members are now more attuned to the risks and benefits of cancer screening, thus, it is imperative that physicians understand the screening tools and how to interpret the information they provide. We reviewed the current literature regarding the cancer risks for individuals with a family history of prostate cancer, colon cancer, and melanoma, the current screening recommendations for family members, and actual screening practices of individuals with a family history of these malignancies. This review should serve as a guide for physicians and cancer control planners when advising their patients and the public regarding screening decisions.

Familial risks and temporal incidence trends of multiple myeloma

In several cancer registration areas, the trends in the incidence and mortality of multiple myeloma (MM) have been rising over the last few decades. Pedigrees studies on families with multiple affected members have supported the hypothesis of a contributing hereditary etiology of MM due to shared genetic factors. The aim of our study was twofold: 1) to assess incidence trends of MM over the period 1961-2003 using national cancer registry data and; 2) to quantify the familial risk of MM using the 2004 update of the Swedish Family-Cancer Database. For men, the age-standardized rates were 4.33 per 100,000 in 1961-65 and 4.79 in 2001-03. The corresponding rates for women were 2.76 and 3.43. In the elderly, MM rates have risen from 28.7 per 100,000 to 36.2 in men, and from 20.2 to 24.5 in women. MM clustered in families with MM (standardized incidence ratio, SIR=2.45), non-Hodgkin lymphoma (SIR=1.34) and chronic lymphocytic leukaemia (SIR=2.45). No association was found for Hodgkin lymphoma and other leukaemias. Significant associations were found for rectal, stomach, cervical, prostate, bladder, endocrine glands and connective tissue malignancies. Our study adds further evidence that the incidence of MM in Sweden has been constant for several decades. The apparent increase observed in the elderly is, at least in part, attributable to improved diagnostics and certification. MM aggregates in families with MM, chronic lymphocytic leukaemia and, to a lesser extent, with non-Hodgkin lymphoma. If environmental factors can be excluded, the pattern of familial risk of MM is consistent with an autosomal dominant mode of inheritance.

Familial association of prostate cancer with other cancers in the Swedish Family-Cancer Database

BACKGROUND

Familial associations between cancer sites may implicate true familial clustering which is relevant for the identification of new cancer syndromes and for clinical counseling.

METHODS

We used the nation-wide Swedish Family-Cancer Database, containing 10,553 sons and 107,518 fathers with prostate cancer among a total of 170,000 cancer patients in the 0- to 70-year-old offspring generation and over 800,000 cancer patients in the parental generation. We calculated familial standardized incidence ratios (SIRs) and confidence intervals (CIs) for prostate cancers and other cancers in family members.

RESULTS

SIRs for prostate cancer were increased in sons when mothers were diagnosed with breast and ovarian cancers, and when siblings were diagnosed with Hodgkins disease (1.78, N = 18, 95% CI 1.05-2.82) and leukemia (1.39, 43, 1.01-1.88). Liver cancer and melanoma were also in excess in the high-risk families.

CONCLUSIONS

The present analysis, the largest yet carried out, found many novel associations implying familial links between prostate cancer and other sites.

Family history of cancer and the risk of prostate cancer and benign prostatic hyperplasia

We analysed the relation between family history of cancer in first-degree relatives and risk of prostate cancer (PC) and benign prostatic hyperplasia (BPH) using data from a multicentric case-control study conducted in Italy from 1991 to 2002 on 1,294 cases of incident, histologically confirmed PC, 1,369 cases of BPH and 1,451 men admitted to the same network of hospitals for acute, nonneoplastic conditions. Unconditional logistic regression was used to estimate odds ratios (OR) of PC and BPH, adjusted for age and other confounders. Men with a family history of PC had an OR of PC of 4.0 (95% confidence interval [CI] 2.5-6.5), and the risk was higher when the proband was younger, when 2 or more relatives were affected or when the affected relative was a brother. The risk of PC was also increased in men with a family history of cancer of the ovary (OR = 6.2, 95% CI 1.2-32), bladder (OR = 3.5, 95% CI 1.6-7.4) and kidney (OR = 3.1, 95% CI 1.1-8.5). An involvement of breast/ovarian cancer predisposition genes in a small proportion of PCs was suggested by the cluster of these cancers in female relatives of a few PC cases. The risk of BPH was increased in men with a family history of bladder cancer (OR = 2.2, 95% CI 1.0-5.0) but not PC (OR = 1.2, 95% CI 0.7-2.2). Our study adds further information on the association of family history of cancer and risk of PC and is, to our knowledge, the first comprehensive epidemiologic information on family history of cancer and risk of BPH.

Familial risk of prostate cancer in Iceland

OBJECTIVE

To estimate the risk of prostate and other types of cancer among relatives of Icelandic men diagnosed with prostate cancer over a 5-year period.

PATIENTS AND METHODS

The risk ratio (RR) was used to estimate the risk among relatives of 371 patients with prostate cancer, all of whom lived in Iceland and were diagnosed when alive over a 5-year interval (1983-7). Information on cancer incidence was obtained from the population-based Icelandic Cancer Registry, and information on families from a comprehensive genealogical database covering the population of Iceland.

RESULTS

First-degree male relatives were at a 1.7-fold greater age-adjusted risk of prostate cancer (1832 men; 95% confidence interval, CI, 1.28-2.34). The risk was independent of proband's age at diagnosis. First-degree male relatives of patients who died from prostate cancer were at a statistically significantly greater risk of the disease (784 men; RR 2.17; 95% CI 1.34-3.53) and relatives of patients with incidental disease (T1a) were at a greater risk but not statistically significant so (261; RR 1.86; 95% CI 0.75-4.58). Female first-degree relatives were not at greater risk of breast cancer. The risk of kidney cancer was higher in first- and second-degree female relatives, with an RR (n, CI) of 2.50 (1780, 1.10-5.66) and 2.67 (5534, 1.04-6.81), respectively. The risk of kidney cancer was not statistically significantly greater in male relatives.

CONCLUSION

Family history is a risk factor for prostate cancer in Icelandic men. The risk is potentially higher for relatives of patients who die from the disease. Female relatives are not at greater risk of breast cancer but they may be at greater risk of kidney cancer.

Site-specific familial aggregation of prostate cancer

Over the last decade, epidemiologic evidence has accumulated in favor of a significant but heterogeneous hereditary component in prostate cancer (PC) susceptibility. In order to map and clone PC susceptibility genes, stratification of PC families into genetically homogeneous groups appears to be a key issue. Subset definition based on age at diagnosis, presumed mode of inheritance, number of affecteds per family and coaggregation of PC with other cancers has already proven successful in some studies. Previously, the finding of the coaggregation of malignancies of the central nervous system within PC families helped to link a prostate-brain cancer susceptibility gene (CAPB) to chromosome 1p36. In this study, we evaluate the risk of PC and malignancies at other sites among first-degree relatives of a large population-based group of Dutch PC patients. A population-based family case-control study was initiated that included Caucasian PC patients newly diagnosed between July 1996 and December 1999. Information on 12,575 first-degree relatives of 704 PC patients and 1,371 controls was collected through postal questionnaires and telephone interviews. All reported PC in first-degree relatives was verified through medical records. In our population, PC has a strong familial component that is reflected by a 2.9-fold increased risk (95% CI = 2.2-3.9) of PC for first-degree relatives of PC patients. This familial risk was somewhat higher among brothers (hazard ratio = 3.9; 95% CI = 2.4-6.4) compared to fathers (hazard ratio = 2.5; 95% CI = 1.7-3.6). Cancers at other sites did not coaggregate with PC. Our data suggest that familial PC, at least in this Western European population, is site-specific, not part of an inherited cancer syndrome.

Familial aggregation of prostate cancer in African-Americans and white Americans

BACKGROUND

We compared the incidence of prostate cancer in first-degree family members of African-Americans with that in white Americans.

METHODS

A historical cohort design was used to enroll 330 incident cases <80 years of age that were diagnosed at the Houston VA Medical Center between June 9, 1993 and June 8, 1996. We compared incidence rates in the probands' families with the incidence rates found in contemporaneous data from the national and regional Surveillance, Epidemiology, and End-Results (SEER) program.

RESULTS

Three-hundred five probands (41% African-American) had evaluable first-degree relatives (394 African-American, 527 non-African-American). The standardized incidence ratio was 1.61 overall (95% confidence interval (CI): 1.22-2.13) and did not differ between African-American and non-African-American families: 1.58 (1.05-2.29) and 1.65 (1.06-2.45) in African-Americans and non-African-Americans, respectively.

CONCLUSIONS

The similar level of familial aggregation is evidence that the higher incidence of prostate cancer in African-Americans is not attributable to a higher prevalence of germline mutations predisposing to the disease.

A systematic review and meta-analysis of familial prostate cancer risk

OBJECTIVE

To identify published studies quantifying familial prostate cancer risks in relatives of prostate cancer cases and, by meta-analysis, obtain more precise estimates of familial risk according to the family history.

METHODS

Thirteen case-control and cohort studies were identified which have reported risks of prostate cancer in relatives of prostate cancer cases. Pooled estimates of risk for various categories of family history were obtained by calculating the weighted average of the log relative risk (RR) estimates from studies.

RESULTS

The pooled RR (95% confidence interval) in first-degree relatives was 2.5 (2.2-2.8). There was evidence that this was highest in relatives of cases diagnosed before age 60 years and that RRs declined with age. The risk for the few men with two affected relatives was increased 3.5-fold (2.6-4.8). RRs to sons of cases appeared to be lower than in brothers; a complete explanation of this observation is uncertain.

CONCLUSION

Men with a family history of prostate cancer have a significantly greater risk of developing prostate cancer than those with no such history. Risks are greatest for relatives of cases diagnosed when young and those with more than one relative affected.

Age specific and attributable risks of familial prostate carcinoma from the family-cancer database

BACKGROUND

Familial risks by proband status and age are useful for clinical counseling, and they can be used to calculate population-attributable fractions (PAFs), which show the proportion of disease that could be prevented if the cause could be removed.

METHODS

The authors used the nationwide Swedish Family-Cancer Database on 10.2 million individuals and 182,104 fathers and 3710 sons with medically verified prostate carcinoma to calculate age specific familial standardized incidence ratios (SIRs) with 95% confidence intervals (95%CI) and familial PAFs for prostate carcinoma in sons ages 0-66 years.

RESULTS

The incidence of prostate carcinoma was doubled between the years 1961 and 1998. The familial SIRs for prostate carcinoma were 2.38 (95%CI, 2.18-2.59) for men with prostate carcinoma in the father only, 3.75 (95%CI, 2.73-4.95) for men with prostate carcinoma in a brother only, and 9.44 (95%CI, 5.76-14.03) for men with prostate carcinoma in both a father and a brother. The corresponding familial PAFs were 8.86%, 1.78%, and 0.99%, respectively, yielding a total PAF of 11.63%. Age specific risks were shown for the same proband histories. The SIR was 8.05 for prostate carcinoma before age 55 if a brother had been diagnosed before that age. If, in addition, a father was diagnosed at any age, then the SIR was 33.09.

CONCLUSIONS

The authors recommend that having a brother who is diagnosed with prostate carcinoma before age 55 years or having a brother and father who are diagnosed at any age are indications to screen for prostate carcinoma. The familial PAF of prostate carcinoma among a population of sons ages 0-66 years was 11.63%.

Genetic fieldwork for hereditary prostate cancer studies

The success of a genetic family study depends on the recruitment of a sufficient number of unaffected family members. We present our experiences from interviews performed in two family studies, a genetic family study of prostate cancer (PC) and a medical, anthropological, qualitative study. In the genetic family study, 949 PC patients were contacted, and 29% responded. Response rates were higher (44%) among subjects contacted by health providers participating in the study, compared to only 18% of those contacted by letter. Thirty-six pedigrees were ascertained. On average, each family had 3.3 affected relatives. Average age at time of diagnosis was 61.9 years in the probands. 58% of the families reported additional cancers. Breast cancer was reported in 12 families; colon cancer was the second most reported cancer, followed by lung, stomach, and throat cancers. Beliefs about the inheritance of PC were explored with 20 participants. The parental origin of the proband's PC in each family did not significantly affect participants' beliefs about the inheritance of PC. 95% agreed that PC could be inherited from a father to a son. Participants thought that a mother (n = 12) or daughter of a patient (n = 11) could not give PC to their sons. This misperception of the inheritance of PC can result in (1) an underreporting of PC cases in a kindred, and (2) healthy men underestimating their risk of developing PC when the disease runs in the mother's family. Thus health educators and genetic counselors might consider these findings when teaching patients and their relatives about hereditary PC.

Genetic Epidemiology--science and ethics on familial cancers

Genetic epidemiology provides data on cancer etiology, familial risks and genotype-specific risks. These data are useful for clinical counselling and gene identification. The studies require large, unbiased sample sizes and collaboration between research teams, nationally and internationally. A recent study on Nordic twins suggests that in colorectal, breast and prostate cancer, the inherited component ranges between 27 and 42%, far in excess of the known susceptibility genes. The data from the Swedish Family-Cancer Database, particularly on second cancers, also suggest that a main genetic component in cancer is polygenic. The results have implications for design of genetic studies and for clinical counselling.

Cancer risks to spouses and offspring in the Family-Cancer Database

It is generally accepted that cancer is caused by environmental and inherited factors but these are only partially identified. Family studies can be informative but they do not separate shared lifestyles and genes. We estimate familial risks for concordant cancers between spouses in common cancers of both sexes in order to quantify cancer risks from the shared environment. The risks are compared to those seen between parents and offspring in order to estimate the inherited component. The nation-wide Family-Cancer Database was used as the source of family and cancer data. Standardized incidence ratios (SIRs) were calculated for concordant cancer in offspring by parental cancer and in spouses. Among the 23 cancer sites considered, all but two showed an increased SIR for offspring by father or mother. Only two sites, stomach and lung, showed an increase in SIR of concordant cancer among spouses. Additionally, pancreatic cancer and melanoma were increased in couples where at least one spouse was diagnosed before age 50. If both spouses presented melanoma before age 40, SIR was 3.82 for husbands. SIRs of colon, renal, and skin (squamous cell) cancers were unchanged by spouses' concordant cancer. Shared lifestyle among spouses seems to explain only a small proportion of cancer susceptibility. Because lifestyles are likely to differ more between parents and offspring than between spouses, familial cancer risks between parents and offspring are likely to be more due to heritable rather than environmental effects.

Genetic epidemiology of multistage carcinogenesis

It is commonly believed that cancer is a multistage, polygenic disease. Even though conceptually appealing, the evidence supporting the multistage theory remains limited. Most known tumor suppresser genes are associated with monogenic dominant cancers following a two-hit pathway. We review results from a recent twin study on 90000 individuals that give support to the multistage theory. Statistically significant heritability estimates were shown for cancers of the colorectum (35%), breast (27%), and prostate (42%). These estimates are much higher than those obtained from family studies in which parents and offspring, or sibs are compared. The difference can be accounted for by the involvement of many genes. A polygenic cancer would show small effects in family studies but large effects in twin studies. We present calculations on the decrease in familial risks when the number of genes involved increases or when the penetrance decreases. We test the apparent number of stages involved in the main cancers from the Swedish Family-Cancer Database. The logarithms of the slopes suggest large differences in the apparent numbers of mutations involved in different cancers. The number of mutations required appears to be less in familial breast cancer compared to sporadic breast cancer. Study designs for gene identification should be revised to accommodate polygenic cancers.