Cancer risk in close relatives of women with early-onset breast cancer--a population-based incidence study

Synchronous and metachronous malignancy in endometrial cancer patients treated in a tertiary care center of Thailand

Objective

To evaluate the prevalence and features of non-endometrial cancers in Thai endometrial cancer (EC) patients.

Methods

EC patients treated in our institution were identified and the following data were collected: age, EC stage, histopathology, adjuvant therapy, other cancers, living status, and cause of death.

Results

The mean age of the 344 patients was 56.8±10.8 years. Fifty (14.5%) had other synchronous and metachronous cancers. Mean ages of the patients with or without other cancers were not significantly different, 55.7±10.04 years versus 57.1±11.0 years, respectively (p=0.358). History of any cancer in the family and tumor in the lower uterine segment were more frequent among the patients with other cancers (6.0% vs. 1.7%, p=0.095; 12.0% vs. 1.0%, p<0.001; respectively). Six patients had ≥2 other cancers. Ovarian, breast, and colon were the three most common other cancers. After a median follow-up of 57.1 months, 18.3% of patients had died: 30.0% of patients with other cancers and 16.3% of those without other cancers. The corresponding EC deaths were 14.0% and 11.2%. The 5-year overall survival was significantly lower in patients who had other cancers: 79.3% (95% confidence interval [CI], 68.3 to 90.3) vs. 86.0% (95% CI, 81.7 to 90.3) than in those without (p=0.023). However, the corresponding disease-specific survival was not significantly different: 85.1% (95% CI, 75.5 to 94.7) compared with 89.0% (95% CI, 85.1 to 92.9), respectively (p=0.514).

Conclusion

Thai EC patients had a high incidence of other cancers. Overall survival of EC patients who had other cancers was worse than those without, while disease-specific survival was not significantly different.

Pregnancy after breast cancer. A comprehensive review

Pregnancy after breast cancer treatment has become an important issue since many young breast cancer patients have not completed their family. Generally, these patients should not be discouraged to become pregnant when they want to, since published data suggest no adverse effect of pregnancy on survival. As fertility may be impaired by chemotherapy, different fertility preserving strategies have been developed. Births seem to sustain no adverse effects, while breastfeeding appears to be feasible and safe.

A constant risk for familial breast cancer? A population-based family study

Introduction

The incidence of breast cancer in the unaffected breast of women with previous breast malignancy remains constant after the first diagnosis. We investigated whether there is a similar pattern in the breast cancer incidence in first-degree relatives of breast cancer patients. We studied the risk for breast cancer in mothers at ages older than their daughter's age at diagnosis.

Methods

We analyzed a Swedish population-based cohort with complete family links and calculated incidence rates of breast cancer in mothers of 48,259 daughters diagnosed with breast cancer.

Results

The risk for breast cancer in mothers of breast cancer patients is elevated relative to the background population at all ages. Mothers have an overall incidence of 0.34%/year at ages older than a daughter's age at diagnosis. This rate is not affected to any large extent by the daughter's age at diagnosis. A constant incidence rate of 0.40%/year from age 35 years onward is seen in mothers of breast cancer patients diagnosed before 35 years of age. For mothers of daughters diagnosed at age 35 to 44 years the incidence pattern is less clear, with the rate being stable for approximately 20 years after the daughter's age at diagnosis and rising thereafter. Older age at a daughter's diagnosis (≥ 45 years) appears to confer an age-dependent increase in incidence in the mother.

Conclusions

Incidence of familial breast cancer in first-degree relatives may increase to a high and constant level by a predetermined age that is specific to each family. This phenomenon appears inconsistent with accepted theories of malignant transformation.

Breast cancer risks in women with a family history of breast or ovarian cancer who have tested negative for a BRCA1 or BRCA2 mutation

Genetic testing for mutations in BRCA1 and BRCA2 is available in Canada for women with a significant family history of breast cancer. For the majority of tested women, a BRCA1 or BRCA2 mutation is not found, and counselling regarding breast cancer risk is based on the review of the pedigree. In this prospective study, we estimate breast cancer risks in women with a family history of breast cancer and for whom the proband tested negative for a mutation in BRCA1 or BRCA2. Families with two or more breast cancers under the age of 50 years, or with three cases of breast cancer at any age, and who tested negative for a BRCA1 or BRCA2 mutation were identified. Follow-up information on cancer status was collected on all first-degree relatives of breast cancer cases. The standardised incidence ratios (SIRs) for breast cancer were calculated by dividing the observed numbers of breast cancer by the expected numbers of breast cancers, based on the rates in the provincial cancer registries. A total of 1492 women from 365 families were included in the analyses. The 1492 first-degree relatives of breast cancer cases contributed 9109 person-years of follow-up. Sixty-five women developed breast cancer, compared to 15.2 expected number (SIR=4.3). The SIR was highest for women under the age of 40 (SIR=14.9) years and decreased with increasing age. However, the absolute risk was higher for women between the age of 50 and 70 (1% per year) years than for women between 30 and 50 (0.4% per year) years of age. There was no elevated risk for ovarian, colon or any other form of cancer. Women with a significant family history of breast cancer (ie, two or more breast cancers under the age of 50 years, or three or more breast cancers at any age), but who test negative for BRCA mutations have approximately a four-fold risk of breast cancer. Women in these families may be candidates for tamoxifen chemoprevention and/or intensified breast screening with an MRI.

Benign breast disease among first-degree relatives of young breast cancer patients

Benign breast disease is associated with increased risk of breast cancer. To further clarify whether there is a genetic link between benign and malignant breast lesions, the authors identified 14,648 first-degree female relatives of 8,807 patients in whom breast cancer was diagnosed at <50 years of age by using Danish nationwide cancer and population registers. Hospital register data were used to follow the relatives for occurrence of benign breast disease from 1977 to 2003 and to calculate rates of benign breast disease in the general population of Danish women for comparison. Risk for relatives was increased for benign breast diseases (observed/expected ratio = 1.54, 95% confidence interval: 1.42, 1.66), particularly for relatives aged <40 years. Higher risks were observed after breast cancer had been diagnosed in the family; however, an increased risk for relatives aged <50 years (observed/expected ratio = 1.24, 95% confidence interval: 1.02, 1.51) was present before breast cancer was diagnosed in the family. Enhanced surveillance of close relatives of breast cancer patients seems to be an important factor to address when investigating the association between benign breast disease and familial breast cancer. A genetic link between benign breast disease and breast cancer was indicated by our data but needs to be confirmed in future studies.

Mortality from cancer and other causes in parents of children with cancer: a population-based study in Piedmont, Italy

This population-based study (the largest on this issue conducted in Southern Europe) has examined mortality among the parents of 2622 children diagnosed with cancer in Piedmont during 1967-1994. Parents were followed up from the date of the index child's birth until the end of 2000, yielding a total of 118 090.7 person-years of observation. Standardized mortality ratios (SMRs) were estimated using mortality rates for the whole population of Piedmont as the reference. Among mothers, total mortality was similar to that expected [SMR 1.02, 95% confidence interval (CI) 0.85-1.23, 117 cases]. A reduced risk of mortality was seen in fathers (SMR 0.91, 95% CI 0.81-1.02, 293 cases); this was largely due to causes other than cancer and the reduction in risk disappeared after the index child's death (SMR 0.98, 95% CI 0.84-1.15, 168 cases). Deaths from cancers of the lymphohaematopoietic system were in excess among mothers (SMR=2.13, 95% CI 1.02-3.92, 10 cases) and breast cancer deaths were in excess specifically among mothers of leukaemic children (SMR 2.32, 95% CI 1.16-4.14, 11 cases). Three mothers dying with breast cancer had index children who had been diagnosed with a bone sarcoma. Parental cancer of the respiratory tract was significantly associated with both tumours of the central nervous system and Hodgkin's lymphoma in the index child. The excess risks identified here may be due to genetic factors or due to parental psychological stress consequent to cancer in a child that may lead to increased mortality either through the direct effects of stress or through consequent changes in lifestyle.

Cancer incidence in first-degree relatives of a population-based set of cases of early-onset breast cancer

Reliable determination of familial risks for cancer is important for clinical counselling, cancer prevention and understanding cancer aetiology. Family-based gene identification efforts may be targeted if the risks are well characterised and the mode of inheritance is identified. Early-onset breast cancer in a family member is a risk indicator for cancer among first-degree relatives; however, the familial risk pattern has not been assessed fully in population-based incidence studies. We estimated the risks for cancers of the breast, ovary and other sites among the first-degree relatives of 8868 patients in whom breast cancer was diagnosed before they reached the age of 50 years (diagnosed during the period 1943-1999). Population registers and parish records were used to identify 31,235 first-degree relatives, who were followed up to 31 December 2002 for occurrence of cancer by linkage to the Danish Cancer Registry. The observed incidence rates were compared with national rates adjusted for age, sex and calendar period. Overall, 39% of the 674 cases of breast cancer and 43% of the 143 cases of ovarian cancer among relatives were associated with a diagnosis of early-onset breast cancer in a family member. Among relatives under 50 years of age, the proportions were 56% and 58%, respectively, and among relatives 50 years or above the proportions were approximately 30% and 10%. In addition, a slightly but significantly increased risk for cancer of the cervix uteri was observed among relatives, and among those under 50 years of age, we found significantly increased risks for cancers of the colon and gall-bladder. In conclusion, the excess risk for breast cancer in first-degree relatives is large and remains sizable in the subgroup of female relatives aged 50 years or older, and that mutations in BRCA1/2 seem to explain only half of breast cancer cases attributable to family history.

Familial Waldenstrom's macroglobulinemia

The etiology of Waldenstrom's macroglobulinemia (WM) is unknown. A possible role for genetic factors has been suggested by reports of familial clustering of WM. However, it is not yet possible to define the proportion of all WM that occurs in the familial setting. Review of the data on the 12 families published since 1962 suggests that familial WM may differ from sporadic disease in certain respects. Among these families, there is a pronounced occurrence of a variety of immunologic abnormalities in the relatives of WM cases. Notably, the prevalence of IgM monoclonal gammopathy (IgM MG) in first-degree relatives of WM cases was reported to be as high as 6.3%, representing a 10-fold increase relative to general population estimates. IgM MG has been shown to progress to WM at a rate of approximately 1.5% per year in a large case series; whether this rate of progression is altered in familial WM is unknown. Although limited by small numbers and a lack of systematic ascertainment and evaluation, these data are intriguing and provide a compelling basis for further study and systematic investigation of WM in families.

Heritable breast cancer in twins

Known major mutations such as BRCA1/2 and TP53 only cause a small proportion of heritable breast cancers. Co-dominant genes of lower penetrance that regulate hormones have been thought responsible for most others. Incident breast cancer cases in the identical (monozygotic) twins of representative cases reflect the entire range of pertinent alleles, whether acting singly or in combination. Having reported the rate in twins and other relatives of cases to be high and nearly constant over age, we now examine the descriptive and histological characteristics of the concordant and discordant breast cancers occurring in 2310 affected pairs of monozygotic and fraternal (dizygotic) twins in relation to conventional expectations and hypotheses. Like other first-degree relatives, dizygotic co-twins of breast cancer cases are at higher than usual risk (standardised incidence ratio (SIR)=1.7, CI=1.1-2.6), but the additional cases among monozygotic co-twins of cases are much more numerous, both before and after menopause (SIR=4.4, CI=3.6-5.6), than the 100% genetic identity would predict. Monozygotic co-twin diagnoses following early proband cancers also occur more rapidly than expected (within 5 years, SIR=20.0, CI=7.5-53.3). Cases in concordant pairs represent heritable disease and are significantly more likely to be oestrogen receptor-positive than those of comparable age from discordant pairs. The increase in risk to the monozygotic co-twins of cases cannot be attributed to the common environment, to factors that cumulate with age, or to any aggregate of single autosomal dominant mutations. The genotype more plausibly consists of multiple co-existing susceptibility alleles acting through heightened susceptibility to hormones and/or defective tumour suppression. The resultant class of disease accounts for a larger proportion of all breast cancers than previously thought, with a rather high overall penetrance. Some of the biological characteristics differ from those of breast cancer generally.

Risk assessment & genetic testing

Ovarian cancer is the fifth most common cause of cancer death in women in Western countries and family history is one of the strongest known risk factors. Approximately 5 to 13% of all ovarian cancer cases are caused by the inheritance of cancer predisposing genes with an autosomal pattern of transmission. The inherited fraction of ovarian cancer may differ between populations. Based on analysis of familial ovarian cancer pedigrees and other epidemiological studies, three hereditary ovarian cancer syndromes have been defined. The identification of the genes responsible for most hereditary ovarian cancers has open a new area of early detection methods and preventive procedures specifically dedicated to women identified as carrying ovarian cancer predisposing genes. Predictive oncology is best performed by a dedicated unit with professionals aware of all the issues surrounding genetic testing.

Mutations of the BRCA1 and BRCA2 genes in patients with bilateral breast cancer

Mutations of the BRCA1 or BRCA2 genes have been shown to strongly predispose towards the development of contralateral breast cancer in patients from large multi-case families. In order to test the hypothesis that BRCA1 and BRCA2 mutations are more frequent in patients with bilateral breast cancer, we have investigated a hospital-based series of 75 consecutive patients with bilateral breast cancer and a comparison group of 75 patients with unilateral breast cancer, pairwise matched by age and family history, for mutations in the BRCA1 and BRCA2 genes. Five frameshift deletions (517delGT in BRCA1; 4772delA, 5946delCT, 6174delT and 8138del5 in BRCA2) were identified in patients with bilateral disease. No further mutations, apart from polymorphisms and 3 rare unclassified variants, were found after scanning the whole BRCA1 and BRCA2 coding sequence. Three pathogenic BRCA1 mutations (Cys61Gly, 3814del5, 5382insC) were identified in the group of patients with unilateral breast cancer. The frequencies of common BRCA1 and BRCA2 missense variants were not different between the 2 groups. In summary, we did not find a significantly increased prevalence of BRCA1 and BRCA2 mutations in a hospital-based cohort of German patients with bilateral breast cancer. We conclude that bilaterality of breast cancer on its own is not strongly associated with BRCA1 and BRCA2 mutations when adjusted for age and family history. The high frequency of bilateral disease in multi-case breast cancer families may be due to a familial aggregation of additional susceptibility factors modifying the penetrance of BRCA1 and BRCA2 mutations.

BRCA1 and BRCA2 mutation status and cancer family history of Danish women affected with multifocal or bilateral breast cancer at a young age

INTRODUCTION

A small fraction of breast cancer is the result of germline mutations in the BRCA1 and BRCA2 cancer susceptibility genes. Mutation carriers frequently have a positive family history of breast and ovarian cancer, are often diagnosed at a young age, and may have a higher incidence of double or multiple primary breast tumours than breast cancer patients in general.

OBJECTIVES

To estimate the prevalence and spectrum of BRCA1 and BRCA2 mutations in young Danish patients affected with bilateral or multifocal breast cancer and to determine the relationship of mutation status to family history of cancer.

SUBJECTS

From the files of the Danish Breast Cancer Cooperative Group (DBCG), we selected 119 breast cancer patients diagnosed before the age of 46 years with either bilateral (n=59) or multifocal (n=61) disease.

METHODS

DNA from the subjects was screened for BRCA1 and BRCA2 mutations using single strand conformation analysis (SSCA) and the protein truncation test (PTT). Observed and expected cancer incidence in first degree relatives of the patients was estimated using data from the Danish Cancer Registry.

RESULTS

Twenty four mutation carriers were identified (20%), of whom 13 had a BRCA1 mutation and 11 carried a BRCA2 mutation. Two mutations in BRCA1 were found repeatedly in the material and accounted for seven of the 24 (29%) mutation carriers. The mutation frequency was about equal in patients with bilateral (22%) and multifocal breast cancer (18%). The incidence of breast and ovarian cancer was greatly increased in first degree relatives of BRCA1 and BRCA2 mutation carriers, but to a much lesser degree in relatives of non-carriers. An increased risk of cancer was also noted in brothers of non-carriers.

CONCLUSIONS

A relatively broad spectrum of germline mutations was observed in BRCA1 and BRCA2 and most of the mutations are present in other populations. Our results indicate that a diagnosis of bilateral and multifocal breast cancer is predictive of BRCA1 and BRCA2 mutation status, particularly when combined with information on the patients' age at diagnosis and family history of breast/ovarian cancer.

High constant incidence in twins and other relatives of women with breast cancer

The incidence of breast cancer rises steeply between ages 25 and 50, and more slowly thereafter. In contrast, the incidence in the unaffected (contralateral) breast of women who have had breast cancer remains constant at about 0.7% per year for at least the next 20 years after diagnosis, irrespective of age at first diagnosis. The incidence in relatives of the patients seems to show a similar pattern. The incidence in a prospective study of monozygotic twins of patients was approximately constant at 1.3% per year (77 cases), again about 0.7% per breast. At ages older than a patient's age at diagnosis, her mother and sisters have an incidence of 0.3-0.4% per year. Above the index patient's age at diagnosis, the rate in relatives shows no temporal trend and is independent of the patient's age at diagnosis. A statistically simple explanation is that incidence in susceptible women increases to a high constant level by a predetermined age that varies between families, but this seems inconsistent with conventional models of carcinogenesis and susceptibility. The very high incidence in monozygotic twins of patients indicates that a high proportion, and perhaps the majority, of breast cancers arise in a susceptible minority of women.

Prophylactic oophorectomy: clinical considerations

Ovarian cancer usually remains clinically silent until it is far advanced, and is associated with significant morbidity and mortality. In view of the modest impact of adjuvant treatments on survival, much effort is devoted to early detection programs and prevention strategies. However, the usefulness of early detection programs remains to be established, with only one randomized study indicating improved median survival in screened individuals. At present, oral contraceptives and prophylactic oophorectomy are the only options for prevention of ovarian cancer. Indications for prophylactic oophorectomy either as a primary procedure, or secondary to abdominal surgery, will vary according to the estimated risk, and to the individual's perception of that risk. Genetic screening allows better identification of pre-symptomatic individuals who would benefit the most from prophylactic oophorectomy. Data concerning the benefit of prophylactic surgery, and the safety of established or innovative hormone replacement therapies in individuals at risk, are encouraging.

Detection of BRCA1 and BRCA2 mutations in breast cancer families by a comprehensive two-stage screening procedure

We have developed a 2-stage protocol for BRCA1 and BRCA2 mutation screening from blood spot paper. Stage 1 screening was aimed to analyze patients at highest risk for the most common disease-associated sequence variants listed in the BIC database. Accordingly, stage1 testing implied detection of 18 disease- associated BRCA1 and 9 BRCA2 mutations by adapting the 5' nuclease assay to heterozygote screening. For stage 2 screening, we applied the conformation sensitive gel electrophoresis (CSGE) method by adapting this technique to automated heteroduplex analysis of BRCA1 and BRCA2 using fragment scanning on an ABI 377 sequencing device. Of the 120 patients with a family history of breast and ovarian cancer who took part in this study so far, 45 entered stage 1 testing. Disease-associated mutations were detected in 6 patients by stage 1 testing (13%). For these patients, the final result was available within 10 days. Mutation 300T-->G was found in 2 patients. One patient with mutation 3036delACAA in BRCA2 reported only 1 sister with a multifocal bilateral breast cancer. New disease-associated mutations were detected in 2 of the 114 patients who entered the stage 2 test (1.7%). Of particular interest was 1 patient who was diagnosed with a medullary breast carcinoma at age 39 and who had no family history of breast cancer. We conclude that pre-screening by 5' nuclease assay for the mutations most frequently seen in a given population represents a relatively effective first line of analysis. Subsequent detailed analysis by fluorescence conformation sensitive gel electrophoresis (F-CSGE) and fragment sequencing is a sensitive alternative to full nucleotide sequencing.

Epidemiology, prevention, and early detection of breast cancer

Globally, breast cancer is the third most common form of cancer and the most common among women. The age-adjusted incidence rates of breast cancer are 176% higher in developed than in developing nations. Male breast cancer is rare, but important studies provided risk factor information for comparison with studies of female breast cancer. There has been considerable interest in a possible role of organochlorines and polychlorinated biphenyls in the etiology of breast cancer, but the results of several null studies indicate the likelihood of such associations is extremely remote, providing reassuring news for the public. Prophylactic mastectomy was observed to significantly reduce a woman's chances of developing breast cancer, but it does not lower the risk to zero. Tamoxifen was found to be an effective chemopreventive agent in the Breast Cancer Prevention Trial, but this result was not replicated in two randomized trials in Europe. Striking reductions in the risk for breast cancer were observed for raloxifene in a randomized, placebo-controlled trial that had been designed for the prevention of osteoporosis. A large-scale, randomized trial of tamoxifen-verus-raloxifene among women at increased risk for developing breast cancer is now underway.