Risks for Familial and Contralateral Breast Cancer Interact Multiplicatively and Cause a High Risk

Identifying actionable druggable targets for breast cancer: Mendelian randomization and population-based analyses

BACKGROUND

Drug repurposing provides a cost-effective approach to address the need for breast cancer prevention and therapeutics. We aimed to identify actionable druggable targets using Mendelian randomization (MR) and then validate the candidate drugs using population-based analyses.

METHODS

We identified genetic instruments for 1406 actionable targets of approved non-oncological drugs based on gene expression, DNA methylation, and protein expression quantitative trait loci (eQTL, mQTL, and pQTL, respectively). Genome-wide association study (GWAS) summary statistics were obtained from the Breast Cancer Association Consortium (122,977 cases, 105,974 controls). We further conducted a nested case-control study using data retrieved from Swedish registers to validate the candidate drugs that were identified from MR analyses.

FINDINGS

We identified six significant MR associations with gene expression levels (TUBB, MDM2, CSK, ULK3, MC1R and KCNN4) and two significant associations with gene methylation levels across 21 CpG islands (RPS23 and MAPT). Results from the nested case-control study showed that the use of raloxifene (targeting MAPT) was associated with 35% reduced breast cancer risk (odds ratio, OR, 0.65; 95% confidence interval, CI, 0.51-0.83). However, usage of estradiol, tolterodine, and nitrofurantoin (also targeting MAPT) was associated with increased breast cancer risk, with adjusted ORs and 95% CI of 1.10 (1.07-1.13), 1.16 (1.09-1.24), and 1.09 (1.05-1.13), respectively. The effect of raloxifene and nitrofurantoin lost significance in further validation analyses using active-comparator and new-user design.

INTERPRETATION

This large-scale MR analysis, combined with population-based validation, identified eight druggable target genes for breast cancer and suggested that raloxifene is an effective chemoprevention against breast cancer.

FUNDING

Swedish Research Council, Cancerfonden, Crafoordska Stiftelsen, Allmänna Sjukhusets i Malmö Stiftelsen för bekämpande av cancer, 111 Project and MAS cancer.

Family history of breast cancer as a second primary malignancy in relatives: a nationwide cohort study

Background

With the increasing number of breast cancer (BC) diagnosed as a second primary malignancy after a first primary non-breast cancer (BCa-2), it is unclear about the familial risk of BC among women with a first-degree relative (FDR, parents or siblings) affected by a BCa-2.

Methods

In this Swedish nationwide cohort study, 5315 women with a FDR affected by BCa-2 and 115,048 women with a FDR affected by BC as the first primary cancer (BCa-1) were followed for the first primary invasive BC diagnosis. Relative risk (RR) of BC was estimated through Poisson regression by using 2,743,777 women without a family history of cancer as reference. The risk was stratified by the diagnostic age of BC in FDR, proband type, the time interval between the first primary cancer and BCa-2 in FDR as well as the site of first primary cancer diagnosed in FDR before BCa-2. We also calculated the cumulative incidence of BC from birth to a specific age for the three groups.

Results

The cumulative incidence from birth to age 70 was 10% among women with a family history of BCa-2. The RR of BC with a family history of BCa-2 (RR, 1.68, 95%CI, 1.49 to 1.88) was comparable to that with BCa-1 (1.68, 1.63 to 1.73). The risk was largely consistent irrespective of proband type. The age of onset of BCa-2 in FDR (RR _early-onset, 1.72 vs. RR _late-onset 1.67) had less influence on the risk compared to BCa-1 in FDR (1.89 vs. 1.63). In the analysis stratified by the time between the first primary cancer and BCa-2 in relatives, the risks were largely similar. For the site of first primary cancer diagnosed in FDR before BCa-2, the increased BC risk was found in women whose FDRs were diagnosed with first primary gastric, colorectal, endometrial, ovarian, nervous system and endocrine gland cancers, and non-Hodgkin lymphoma.

Conclusions

Women with a family history of BCa-2 have a similar overall BC risk as those with a family history of BCa-1. The risk varied according to the site of first primary cancer diagnosed in FDR before BCa-2.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08925-y.

Machine learning on genome-wide association studies to predict the risk of radiation-associated contralateral breast cancer in the WECARE Study

The purpose of this study was to identify germline single nucleotide polymorphisms (SNPs) that optimally predict radiation-associated contralateral breast cancer (RCBC) and to provide new biological insights into the carcinogenic process. Fifty-two women with contralateral breast cancer and 153 women with unilateral breast cancer were identified within the Women’s Environmental Cancer and Radiation Epidemiology (WECARE) Study who were at increased risk of RCBC because they were ≤ 40 years of age at first diagnosis of breast cancer and received a scatter radiation dose > 1 Gy to the contralateral breast. A previously reported algorithm, preconditioned random forest regression, was applied to predict the risk of developing RCBC. The resulting model produced an area under the curve (AUC) of 0.62 (p = 0.04) on hold-out validation data. The biological analysis identified the cyclic AMP-mediated signaling and Ephrin-A as significant biological correlates, which were previously shown to influence cell survival after radiation in an ATM-dependent manner. The key connected genes and proteins that are identified in this analysis were previously identified as relevant to breast cancer, radiation response, or both. In summary, machine learning/bioinformatics methods applied to genome-wide genotyping data have great potential to reveal plausible biological correlates associated with the risk of RCBC.

Risk factors for metachronous contralateral breast cancer: A systematic review and meta-analysis

BACKGROUND

The risk of developing metachronous contralateral breast cancer (CBC) is a recurrent topic at the outpatient clinic. We aimed to provide CBC risk estimates of published patient, pathological, and primary breast cancer (PBC) treatment-related factors.

METHODS

PubMed was searched for publications on factors associated with CBC risk. Meta-analyses were performed with grouping of studies by mutation status (i.e., BRCA1, BRCA2, CHEK2 c.1100delC), familial cohorts, and general population-based cohorts.

RESULTS

Sixty-eight papers satisfied our inclusion criteria. Strong associations with CBC were found for carrying a BRCA1 (RR = 3.7; 95%CI:2.8-4.9), BRCA2 (RR = 2.8; 95%CI:1.8-4.3) or CHEK2 c.1100delC (RR = 2.7; 95%CI:2.0-3.7) mutation. In population-based cohorts, PBC family history (RR = 1.8; 95%CI:1.2-2.6), body mass index (BMI) ≥30 kg/m² (RR = 1.5; 95%CI:1.3-1.9), lobular PBC (RR = 1.4; 95%CI:1.1-1.8), estrogen receptor-negative PBC (RR = 1.5; 95%CI:1.0-2.3) and treatment with radiotherapy <40 years (RR = 1.4; 95%CI:1.1-1.7) was associated with increased CBC risk. Older age at PBC diagnosis (RR per decade = 0.93; 95%CI:0.88-0.98), and treatment with chemotherapy (RR = 0.7; 95%CI:0.6-0.8) or endocrine therapy (RR = 0.6; 95%CI:0.5-0.7) were associated with decreased CBC risk.

CONCLUSIONS

Mutation status, family history, and PBC treatment are key factors for CBC risk. Age at PBC diagnosis, BMI, lobular histology and hormone receptor status have weaker associations and should be considered in combination with key factors to accurately predict CBC risk.

Second primary cancer after female breast cancer: Familial risks and cause of death

Background

With continuous increases in survival rates following breast cancer (BC) diagnosis, the challenge of multiple primary cancers has become an issue. The data on familial risk of SPCs after BC diagnosis and the related mortality in BC patients are scarce.

Methods

A total of 87 752 female BC patients were followed for SPC diagnoses and records of death. Relative risks (RRs) of SPC in BC patients who had first‐degree relatives (parents or siblings) affected by the same cancer were compared to the patients without family history. Causes of death were compared between patients with and without SPC.

Results

After a median follow‐up of 5 years, 14 952 BC patients developed SPCs, among which 10 280 (68.8%) had first‐degree relatives diagnosed with cancer. Familial risks were significant for 14 site‐specific SPCs, and the highest risk was for second ovarian cancer (RR = 6.28, 95%CI: 4.50‐8.75), compared to those without family history (1.49, 1.34‐1.65). In patients with SPC, SPC was the main cause of death, including diverse cancers and BC in approximately equal proportions.

Conclusions

Family history contributed to the excess number of patients with SPCs, and SPC was the leading cause of death in patients with SPC. Taking family history at diagnosis of BC may provide warning signs with regard to possible subsequent SPCs and may offer possibilities for counseling, intervention and management.

Family history contributed to the excess number of BC patients with SPC. SPC was found the leading cause of death in BC patients with SPC.

The association between prognosis of breast cancer and first-degree family history of breast or ovarian cancer: a systematic review and meta-analysis

Whether a positive family history of breast cancer or ovarian cancer (FHBOC) would affect the prognosis of breast cancer is still up for debate and further study. This meta-analysis was performed to clarify this issue. We reviewed two databases (PubMed and CNKI) for research articles published at any time from the inception of these databases to April 1, 2016 for articles detecting the impact of FHBOC on the prognosis of breast cancer. A meta-analysis was conducted to generated combined hazard ratios (HR) with 95% confidence intervals (CI) for overall survival (OS) and breast cancer-specific survival (BCSS). Eighteen studies were included in our qualitative analysis, with 15 studies ultimately part of the quantitative analysis. The pooled results demonstrated that a positive FHBOC was associated with better OS (0.89, 95% CI 0.83-0.95) and BCSS (0.90, 95% CI 0.82-0.99). In subgroup analyses, several subgroups (maximally adjusted studies, population based studies, high quality studies, family history of breast cancer, studies from Europe, studies from Asia, 1 affected relative, or tumor size > 2 cm), a positive first-degree FHBOC was associated with better prognosis of breast cancer. Notably, for those patients who underwent breast-conserving surgery, first-degree FHBOC was not a risk factor for OS (HR 1.08, 95% CI 0.53-2.21). Our meta-analysis demonstrated that a first-degree FHBOC was associated with better OS and BCSS in patients with breast cancer. These findings support that clinical management should not differ between women with and without FHBOC.

Breast screening for survivors of breast cancer: A systematic review

There is a large and growing population of women who have a personal history of breast cancer (PHBC). This systematic review was undertaken to explore the outcomes of surveillance mammography in breast cancer survivors, and to examine the evidence for screening these women within an organized population-based screening program. We searched Cochrane Central Register of Controlled Trials (CENTRAL Issue 6, 2015), OVID MEDLINE and EMBASE (January 2012 to June 22, 2015) for English-language studies of surveillance of the target population. A study author extracted study outcomes, which were audited by a research assistant. One systematic review and 5 primary studies were included. These showed that surveillance mammography may reduce breast cancer-specific mortality through early/asymptomatic detection (Hazard Ratio for those without compared to with symptoms:HR: 0.64, 95% CI 0.55 - 0.74). Three studies showed that semi-annual mammography is likely not of greater benefit than annual mammography. No evidence was found to suggest that surveillance mammography for women with a PHBC should not be conducted within an organized screening program. The small evidence-base had a high level of heterogeneity in populations, interventions and outcomes. Based on this review, organized screening programs should reassess their guidelines on surveillance mammography and consider including women with a PHBC.

Hormone receptor status of a first primary breast cancer predicts contralateral breast cancer risk in the WECARE study population

BACKGROUND

Previous population-based studies have described first primary breast cancer tumor characteristics and their association with contralateral breast cancer (CBC) risk. However, information on influential covariates such as treatment, family history of breast cancer, and BRCA1/2 mutation carrier status was not available. In a large, population-based, case-control study, we evaluated whether tumor characteristics of the first primary breast cancer are associated with risk of developing second primary asynchronous CBC, overall and in subgroups of interest, including among BRCA1/2 mutation non-carriers, women who are not treated with tamoxifen, and women without a breast cancer family history.

METHODS

The Women's Environmental Cancer and Radiation Epidemiology Study is a population-based case-control study of 1521 CBC cases and 2212 individually-matched controls with unilateral breast cancer. Detailed information about breast cancer risk factors, treatment for and characteristics of first tumors, including estrogen receptor (ER) and progesterone receptor (PR) status, was obtained by telephone interview and medical record abstraction. Multivariable risk ratios (RRs) and 95% confidence intervals (CIs) were estimated in conditional logistic regression models, adjusting for demographics, treatment, and personal medical and family history. A subset of women was screened for BRCA1/2 mutations.

RESULTS

Lobular histology of the first tumor was associated with a 30% increase in CBC risk (95% CI 1.0-1.6). Compared to women with ER+/PR+ first tumors, those with ER-/PR- tumors had increased risk of CBC (RR = 1.4, 95% CI 1.1-1.7). Notably, women with ER-/PR- first tumors were more likely to develop CBC with the ER-/PR- phenotype (RR = 5.4, 95% CI 3.0-9.5), and risk remained elevated in multiple subgroups: BRCA1/2 mutation non-carriers, women younger than 45 years of age, women without a breast cancer family history, and women who were not treated with tamoxifen.

CONCLUSIONS

Having a hormone receptor negative first primary breast cancer is associated with increased risk of CBC. Women with ER-/PR- primary tumors were more likely to develop ER-/PR- CBC, even after excluding BRCA1/2 mutation carriers. Hormone receptor status, which is routinely evaluated in breast tumors, may be used clinically to determine treatment protocols and identify patients who may benefit from increased surveillance for CBC.

Family history of cancer other than breast or ovarian cancer in first-degree relatives is associated with poor breast cancer prognosis

OBJECTIVE

Whether a first-degree family history of others cancers (FHOC) than breast or ovarian cancer (BOC) is associated with breast cancer prognosis remains unknown. Thus, the aim of the present study was to clarify this issue.

METHODS

Women who were diagnosed with invasive breast cancer at the Renmin Hospital of Wuhan University from 2010 to 2013 were included in the study. The demographic and clinicopathological characteristics of these patients were extracted. FHOC was considered positive for any patient who had a relative who had been diagnosed with cancer other than BOC. Disease-free survival (DFS) was calculated based on the date of diagnosis. DFS was analyzed using the Cox proportional hazards model.

RESULTS

A total of 434 breast cancer patients were included in this study. Among these patients, 61 (14.06%) had a positive FHOC in first-degree relatives. Patients with a positive FHOC tended to have HER2-positive breast cancer (p = 0.03). In the survival analysis, FHOC was associated with poor DFS in both univariate (HR = 2.21 (1.28-3.83), 95% CI: 1.28-3.83, p < 0.01) and multivariate (HR = 2.50, 95% CI: 1.24-5.04, p = 0.01) analyses, especially in patients with luminal A subtypes.

CONCLUSION

The results demonstrated an increased risk of recurrence in breast cancer patients with FHOC, especially in patients with luminal A subtype.

Body mass index, weight change, and risk of second primary breast cancer in the WECARE study: influence of estrogen receptor status of the first breast cancer

Studies examining the relationship between body mass index (BMI) and risk of contralateral breast cancer (CBC) have reported mixed findings. We previously showed that obese postmenopausal women with estrogen receptor (ER)‐negative breast cancer have a fivefold higher risk of CBC compared with normal weight women. In the current analysis, we reexamined this relationship in the expanded Women's Environmental Cancer and Radiation Epidemiology (WECARE) Study, focusing on the impact of menopausal status and ER status of the first breast cancer. The WECARE Study is a population‐based case–control study of young women with CBC (cases, N = 1386) and with unilateral breast cancer (controls, N = 2045). Rate ratios (RR) and 95% confidence intervals (CI) were calculated to assess the relationship between BMI and risk of CBC stratified by menopausal and ER status. Positive associations with obesity and weight gain were limited to women who became postmenopausal following their first primary breast cancer. Among those with an ER‐negative first breast cancer, obesity (vs. normal weight) at first diagnosis was associated with an increased risk of CBC (RR = 1.9, 95% CI: 1.02, 3.4). Also, weight gain of ≥10 kg after first diagnosis was associated with an almost twofold increased risk of CBC (RR = 1.9, 95% CI: 0.99, 3.8). These results suggest that women with an ER‐negative first primary cancer who are obese at first primary diagnosis or who experience a large weight gain afterward may benefit from heightened surveillance. Future studies are needed to address the impact of weight loss interventions on risk of CBC.

Reproductive factors, tumor estrogen receptor status and contralateral breast cancer risk: results from the WECARE study

Several reproductive factors are known to be associated with risk of breast cancer; however, relationships between these factors with risk of second primary asynchronous contralateral breast cancer (CBC) have not been widely studied. The Women’s Environmental, Cancer, and Radiation Epidemiology (WECARE) Study is a population-based case-control study of 1521 CBC cases and 2212 individually matched controls with unilateral breast cancer. Using multivariable conditional logistic regression models, we examined associations between reproductive factors and CBC risk, and whether associations differed by estrogen receptor (ER) status and menopausal status of the first breast cancer. Older age at menarche was inversely associated with CBC risk (≥14 vs. ≤11 years risk ratio (RR) = 0.82, 95 % confidence interval (CI) 0.65–1.03, P_trend = 0.02). Among parous women, an increasing number of full-term pregnancies (FTP) was inversely associated with risk (≥4 vs. 1 FTP RR = 0.60, 95 % CI 0.41–0.88, P_trend = 0.005). Ever breast-feeding was inversely associated with CBC risk only among women with ER-negative first tumors (ever vs. never breast-fed RR = 0.69, 95 % CI 0.48–1.00, P_{heterogeneity} = 0.05). Older age at first FTP was inversely associated with CBC risk among women with ER-negative first tumors (≥30 vs. <20 years old RR = 0.66, 95 % CI 0.35–1.27, P_trend = 0.03), but suggestively positively associated with risk among women with ER-positive first tumors (P_{heterogeneity} = 0.03). Young age at menarche and low parity, both risk factors for first primary breast cancer, were also associated with overall CBC risk. Reductions in risk associated with breast-feeding were limited to women with ER-negative first tumors, who are at higher CBC risk than women with ER-positive primaries.

Long-term effects of first degree family history of breast cancer in young women: Recurrences and bilateral breast cancer

BACKGROUND

The aim of this study is to analyze the impact of first degree relative (FDR) of young breast cancer patients.

METHODS

Data were used from our prospective population-based cohort study which started in 1983. The family history (FH) was registered with regard to FDR: the presence or absence of invasive breast cancer in none vs. one or more FDRs at any age.

RESULTS

A total of 1109 women, ≤50 years with 1128 breast conserving treatments was seen. The incidence of FDR was 17.0% for one FDR and 3.2% ≥2 FDR. The three groups, none, 1 or ≥2 FDR, were comparable. The local failure rate is comparable for all three groups. Women with a positive FH and metachronous bilateral breast cancer (MBBC) showed a lower local failure (HR 0.2; 95% CI 0.05-0.8). A positive FH was an independent predictor for a better disease-specific survival (HR 0.6; 95% CI 0.4-0.9).

CONCLUSION

A positive FH, based on FDR implies a better prognosis in relation to survival for young women treated with BCT. In contrast to no FH for FDR, MBBC in women with a positive FH was not associated with an increased risk of local recurrence.

Imaging surveillance programs for women at high breast cancer risk in Europe: Are women from ethnic minority groups adequately included? (Review)

Women from ethnic minority groups, including immigrants and refugees are reported to have low breast cancer (BC) screening rates. Active, culturally-sensitive outreach is vital for increasing participation of these women in BC screening programs. Women at high BC risk and who belong to an ethnic minority group are of special concern. Such women could benefit from ongoing trials aimed at optimizing screening strategies for early BC detection among those at increased BC risk. Considering the marked disparities in BC survival in Europe and its enormous and dynamic ethnic diversity, these issues are extremely timely for Europe. We systematically reviewed the literature concerning European surveillance studies that had imaging in the protocol and that targeted women at high BC risk. The aim of the present review was thereby to assess the likelihood that women at high BC risk from minority ethnic groups were adequately included in these surveillance programs. Twenty-seven research groups in Europe reported on their imaging surveillance programs for women at increased BC risk. The benefit of strategies such as inclusion of magnetic resonance imaging and/or more intensive screening was clearly documented for the participating women at increased BC risk. However, none of the reports indicated that sufficient outreach was performed to ensure that women at increased BC risk from minority ethnic groups were adequately included in these surveillance programs. On the basis of this systematic review, we conclude that the specific screening needs of ethnic minority women at increased BC risk have not yet been met in Europe. Active, culturally-sensitive outreach is needed to identify minority women at increased BC risk and to facilitate their inclusion in on-going surveillance programs. It is anticipated that these efforts would be most effective if coordinated with the development of European-wide, population-based approaches to BC screening.

Second malignant neoplasms and cardiovascular disease following radiotherapy

Second malignant neoplasms (SMNs) and cardiovascular disease (CVD) are among the most serious and life-threatening late adverse effects experienced by the growing number of cancer survivors worldwide and are due in part to radiotherapy. The National Council on Radiation Protection and Measurements (NCRP) convened an expert scientific committee to critically and comprehensively review associations between radiotherapy and SMNs and CVD, taking into account radiobiology; genomics; treatment (i.e., radiotherapy with or without chemotherapy and other therapies); type of radiation; and quantitative considerations (i.e., dose-response relationships). Major conclusions of the NCRP include: (1) the relevance of older technologies for current risk assessment when organ-specific absorbed dose and the appropriate relative biological effectiveness are taken into account and (2) the identification of critical research needs with regard to newer radiation modalities, dose-response relationships, and genetic susceptibility. Recommendation for research priorities and infrastructural requirements include (1) long-term large-scale follow-up of extant cancer survivors and prospectively treated patients to characterize risks of SMNs and CVD in terms of radiation dose and type; (2) biological sample collection to integrate epidemiological studies with molecular and genetic evaluations; (3) investigation of interactions between radiotherapy and other potential confounding factors, such as age, sex, race, tobacco and alcohol use, dietary intake, energy balance, and other cofactors, as well as genetic susceptibility; (4) focusing on adolescent and young adult cancer survivors, given the sparse research in this population; and (5) construction of comprehensive risk prediction models for SMNs and CVD to permit the development of follow-up guidelines and prevention and intervention strategies.

Variants of uncertain significance in BRCA testing: evaluation of surgical decisions, risk perception, and cancer distress

Studies suggest that patients carrying a BRCA variant of uncertain significance (VUS) may have lingering confusion concerning results interpretation. Counseling for uninformative BRCA-negative (UN) results is thought to be more straightforward, despite the fact that both results lead to similar methods of empiric cancer risk counseling. This study compared surgical choices and perceptions between 71 patients with VUS results and 714 patients with UN results. All patients underwent genetic counseling because of a personal or family history of breast or ovarian cancer between 1997 and 2010, and completed a 2-year follow-up survey. Risk-reducing mastectomy rates in both groups were 7% (p = 1.00) and risk-reducing oophorectomy rates were 5% and 3%, respectively (p = 0.42). The VUS group reported less cancer distress reduction than the UN group (23.0% vs 35.8%, respectively, p = 0.043). Over 90% of both groups found the counseling process helpful. Overall, the study suggests that VUS results disclosed in genetic counseling did not cause excessive surgery or exaggerated cancer distress, though patients with a VUS found counseling somewhat less informative or reassuring. Future research on communication of VUS results, including pre-and post-test counseling, is essential for full realization of the potential for genomic medicine.

Review of risk factors for the development of contralateral breast cancer

BACKGROUND

Women treated for breast cancer have an increased risk for developing metachronous contralateral breast cancer (CBC). Patient perception of this risk is often overestimated and has been found to contribute to the decision to undergo contralateral prophylactic mastectomy. An individual's risk is dependent on both patient and tumor characteristics. This review examines and summarizes the current literature on the factors that affect CBC risk.

DATA SOURCES

English-language publications with the keyword "contralateral breast cancer" were identified through a MEDLINE literature search.

CONCLUSIONS

The global incidence of CBC is decreasing, a trend that is attributed to more effective adjuvant therapies. Patients with BRCA germ-line mutations demonstrate the highest risk for CBC. In the absence of known genetic mutations, patients with strong family histories who are diagnosed at young ages (<35 years) with estrogen receptor-negative index tumors appear to have a higher incidence of CBC.

Incident malignancies among older long-term breast cancer survivors and an age-matched and site-matched nonbreast cancer comparison group over 10 years of follow-up

BACKGROUND

Of the approximately 2.4 million American women with a history of breast cancer, 43% are aged ≥ 65 years and are at risk for developing subsequent malignancies.

METHODS

Women from 6 geographically diverse sites included 5-year breast cancer survivors (N = 1361) who were diagnosed between 1990 and 1994 at age ≥ 65 years with stage I or II disease and a comparison group of women without breast cancer (N = 1361). Women in the comparison group were age-matched and site-matched to breast cancer survivors on the date of breast cancer diagnosis. Follow-up began 5 years after the index date (survivor diagnosis date or comparison enrollment date) until death, disenrollment, or through 15 years after the index date. Data were collected from medical records and electronic sources (cancer registry, administrative, clinical, National Death Index). Analyses included descriptive statistics, crude incidence rates, and Cox proportional hazards regression models for estimating the risk of incident malignancy and were adjusted for death as a competing risk.

RESULTS

Survivors and women in the comparison group were similar: >82% were white, 55% had a Charlson Comorbidity Index of 0, and ≥ 73% had a body mass index ≤ 30 kg/m(2) . Of all 306 women (N = 160 in the survivor group, N = 146 in the comparison group) who developed a first incident malignancy during follow-up, the mean time to malignancy was similar (4.37 ± 2.81 years vs 4.03 ± 2.76 years, respectively; P = .28), whereas unadjusted incidence rates were slightly higher in survivors (1882 vs 1620 per 100,000 person years). The adjusted hazard of developing a first incident malignancy was slightly elevated in survivors in relation to women in the comparison group, but it was not statistically significant (hazard ratio, 1.17; 95% confidence interval, 0.94-1.47).

CONCLUSIONS

Older women who survived 5 years after an early stage breast cancer diagnosis were not at an elevated risk for developing subsequent incident malignancies up to 15 years after their breast cancer diagnosis.

Risk of asynchronous contralateral breast cancer in noncarriers of BRCA1 and BRCA2 mutations with a family history of breast cancer: a report from the Women's Environmental Cancer and Radiation Epidemiology Study

PURPOSE

To fully characterize the risk of contralateral breast cancer (CBC) in patients with breast cancer with a family history who test negative for BRCA1 and BRCA2 mutations.

PATIENTS AND METHODS

From our population-based case-control study comparing women with CBC to women with unilateral breast cancer (UBC), we selected women who tested negative for BRCA1 and BRCA2 mutations (594 patients with CBC/1,119 control patients with UBC). Rate ratios (RRs) and 95% CIs were estimated to examine the association between family history of breast cancer and risk of asynchronous CBC. Age- and family history-specific 10-year cumulative absolute risks of CBC were estimated.

RESULTS

Family history of breast cancer was associated with increased CBC risk; risk was highest among young women (< 45 years) with first-degree relatives affected at young ages (< 45 years; RR, 2.5; 95% CI, 1.1 to 5.3) or women with first-degree relatives with bilateral disease (RR, 3.6; 95% CI, 2.0 to 6.4). Women diagnosed with UBC before age 55 years with a first-degree family history of CBC had a 10-year risk of CBC of 15.6%.

CONCLUSION

Young women with breast cancer who have a family history of breast cancer and who test negative for deleterious mutations in BRCA1 and BRCA2 are at significantly greater risk of CBC than other breast cancer survivors. This risk varies with diagnosis age, family history of CBC, and degree of relationship to an affected relative. Women with a first-degree family history of bilateral disease have risks of CBC similar to mutation carriers. This has important implications for the clinical management of patients with breast cancer with family history of the disease.

Second malignant neoplasms and cardiovascular disease following radiotherapy

Second malignant neoplasms (SMNs) and cardiovascular disease (CVD) are among the most serious and life-threatening late adverse effects experienced by the growing number of cancer survivors worldwide and are due in part to radiotherapy. The National Council on Radiation Protection and Measurements (NCRP) convened an expert scientific committee to critically and comprehensively review associations between radiotherapy and SMNs and CVD, taking into account radiobiology; genomics; treatment (ie, radiotherapy with or without chemotherapy and other therapies); type of radiation; and quantitative considerations (ie, dose-response relationships). Major conclusions of the NCRP include: 1) the relevance of older technologies for current risk assessment when organ-specific absorbed dose and the appropriate relative biological effectiveness are taken into account and 2) the identification of critical research needs with regard to newer radiation modalities, dose-response relationships, and genetic susceptibility. Recommendation for research priorities and infrastructural requirements include 1) long-term large-scale follow-up of extant cancer survivors and prospectively treated patients to characterize risks of SMNs and CVD in terms of radiation dose and type; 2) biological sample collection to integrate epidemiological studies with molecular and genetic evaluations; 3) investigation of interactions between radiotherapy and other potential confounding factors, such as age, sex, race, tobacco and alcohol use, dietary intake, energy balance, and other cofactors, as well as genetic susceptibility; 4) focusing on adolescent and young adult cancer survivors, given the sparse research in this population; and 5) construction of comprehensive risk prediction models for SMNs and CVD to permit the development of follow-up guidelines and prevention and intervention strategies.

Should breast cancer survivors be excluded from, or invited to, organised mammography screening programmes?

BACKGROUND

The prevalence of breast cancer in developed countries has steadily risen over recent decades. Immediate and long-term health needs of patients, including preventive care and screening services, are receiving increasing attention. A question still unresolved is whether breast cancer survivors should receive mammographic surveillance in the clinical or screening setting and, thus, whether they should be excluded from, or invited to, organised mammography screening programmes. The objective of this article is to discuss the many contradictory aspects of this matter.

DISCUSSION

Problems with mammographic surveillance of breast cancer survivors include: weak evidence of a reduction in mortality; lack of evidence in favour of one setting or the other; lack of evidence-based guidelines for the frequency and duration of surveillance; disproportionate emphasis placed on the first few years post-treatment, probably dictated by surgical and oncological priorities; a variety of screening policies, as these women are permanently or temporarily or partially excluded from many - but not all - organised screening programmes worldwide; an even greater disparity in follow-up protocols used in the clinical setting; a paucity of data on compliance to mammographic surveillance in both settings; and a difficulty in coordinating the roles of health care providers. In the future, the use of mammography in breast cancer survivors will be influenced by the inclusion of women aged > 69 years in organised screening programmes and the implementation of multidisciplinary breast units, and will probably be investigated by research activities on individual risk assessment and risk-tailored screening. In the interim, current problems can be partially alleviated with some technical solutions in screening data recording, patient flows, and care coordination.

SUMMARY

Mammographic surveillance of breast cancer survivors is situated at the crossroads of numerous different specialist areas of breast cancer control and management. The solutions for current problems probably lie in some important modifications in the conventional screening procedure that are underway or under study. These developments appear to be directed towards a partial modification of the screening rationale, with an adaptation to meet the diversified breast care needs of women. The complexity of the matter constitutes a call to action for several entities to eliminate the barriers to effective research in this field.

Cost-effectiveness of contralateral prophylactic mastectomy versus routine surveillance in patients with unilateral breast cancer

PURPOSE

Contralateral prophylactic mastectomy (CPM) rates in women with unilateral breast cancer are increasing despite controversy regarding survival advantage. Current scrutiny of the medical costs led us to evaluate the cost-effectiveness of CPM versus routine surveillance as an alternative contralateral breast cancer (CBC) risk management strategy.

METHODS

Using a Markov model, we simulated patients with breast cancer from mastectomy to death. Model parameters were gathered from published literature or national databases. Base-case analysis focused on patients with average-risk breast cancer, 45 years of age at treatment. Outcomes were valued in quality-adjusted life-years (QALYs). Patients' age, risk level of breast cancer, and quality of life (QOL) were varied to assess their impact on results.

RESULTS

Mean costs of treatment for women age 45 years are comparable: $36,594 for the CPM and $35,182 for surveillance. CPM provides 21.22 mean QALYs compared with 20.93 for surveillance, resulting in an incremental cost-effectiveness ratio (ICER) of $4,869/QALY gained for CPM. To prevent one CBC, six CPMs would be needed. CPM is no longer cost-effective for patients older than 70 years (ICER $62,750/QALY). For BRCA-positive patients, CPM is clearly cost-effective, providing more QALYs while being less costly. In non-BRCA patients, cost-effectiveness of CPM is highly dependent on assumptions regarding QOL for CPM versus surveillance strategy.

CONCLUSION

CPM is cost-effective compared with surveillance for patients with breast cancer who are younger than 70 years. Results are sensitive to BRCA-positive status and assumptions of QOL differences between CPM and surveillance patients. This highlights the importance of tailoring treatment for individual patients.

Risk factors for metachronous contralateral breast cancer suggest two aetiological pathways

Although many studies show an increased risk of metachronous contralateral breast cancer (CBC) in women with a positive family history and young age at diagnosis of the initial breast cancer, the aetiological pathways are still enigmatic. In a cohort of 8478 primary breast cancer patients diagnosed between 1975 and 2006, 558 cases of metachronous CBC were identified. Using multivariate Cox proportional hazards models, we analysed risk factors assessed at the time of the first primary tumour, including patient demographics, tumour characteristics and treatment among 4681 breast cancer patients for whom data on key variables were available. The analysis was performed separately in patients who developed CBC without and with prior recurrence(s). Risk of CBC without prior recurrent disease was increased by a positive family history [adjusted relative risk (RR) 2.8 (95% confidence interval (CI) 1.4-5.5)]; and decreased by endocrine treatment [RR 0.6 (95% CI 0.4-1.0)]. We found an increased risk of CBC with prior recurrent disease with younger age [RR 1.2 (95% CI 1.4-3.0)]; positive family history [RR 2.1 (95%CI 0.8-5.0)]; and extensive lymph node involvement [RR 2.0 (95% CI 1.2-3.6)]. Our results suggest that nodal status of the primary tumour may be as important a risk factor as family history or age, which indicates a high susceptibility to breast cancer or an impaired host defence mechanism. It may also imply that some CBCs are metastases from the first primary tumour, particularly in patients who present with recurrent disease before CBC.

Radiation exposure, the ATM Gene, and contralateral breast cancer in the women's environmental cancer and radiation epidemiology study

BACKGROUND

Ionizing radiation is a known mutagen and an established breast carcinogen. The ATM gene is a key regulator of cellular responses to the DNA damage induced by ionizing radiation. We investigated whether genetic variants in ATM play a clinically significant role in radiation-induced contralateral breast cancer in women.

METHODS

The Women's Environmental, Cancer, and Radiation Epidemiology Study is an international population-based case-control study nested within a cohort of 52,536 survivors of unilateral breast cancer diagnosed between 1985 and 2000. The 708 case subjects were women with contralateral breast cancer, and the 1397 control subjects were women with unilateral breast cancer matched to the case subjects on age, follow-up time, registry reporting region, and race and/or ethnicity. All women were interviewed and underwent full mutation screening of the entire ATM gene. Complete medical treatment history information was collected, and for all women who received radiotherapy, the radiation dose to the contralateral breast was reconstructed using radiotherapy records and radiation measurements. Rate ratios (RRs) and corresponding 95% confidence intervals (CIs) were estimated by using multivariable conditional logistic regression. All P values are two-sided.

RESULTS

Among women who carried a rare ATM missense variant (ie, one carried by <1% of the study participants) that was predicted to be deleterious, those who were exposed to radiation (mean radiation exposure = 1.2 Gy, SD = 0.7) had a statistically significantly higher risk of contralateral breast cancer compared with unexposed women who carried the wild-type genotype (0.01-0.99 Gy: RR = 2.8, 95% CI = 1.2 to 6.5; > or =1.0 Gy: RR = 3.3, 95% CI = 1.4 to 8.0) or compared with unexposed women who carried the same predicted deleterious missense variant (0.01-0.99 Gy: RR = 5.3, 95% CI = 1.6 to 17.3; > or =1.0 Gy: RR = 5.8, 95% CI = 1.8 to 19.0; P(trend) = .044).

CONCLUSIONS

Women who carry rare deleterious ATM missense variants and who are treated with radiation may have an elevated risk of developing contralateral breast cancer. However, the rarity of these deleterious missense variants in human populations implies that ATM mutations could account for only a small portion of second primary breast cancers.

Second primary breast cancer occurrence according to hormone receptor status

BACKGROUND

Contralateral second primary breast cancers occur in 4% of female breast cancer survivors. Little is known about differences in risk for second primary breast cancers related to the estrogen and progesterone receptor (hormone receptor [HR]) status of the first tumor.

METHODS

We calculated standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for contralateral primary breast cancers among 4927 women diagnosed with a first breast cancer between January 1, 1992, and December 31, 2004, using the National Cancer Institute's Surveillance, Epidemiology, and End Results database.

RESULTS

For women whose first breast tumors were HR positive, risk of contralateral primary breast cancer was elevated, compared with the general population, adjusted for age, race, and calendar year (SIR = 2.22, 95% CI = 2.15 to 2.29, absolute risk [AR] = 13 cases per 10 000 person-years [PY]), and was not related to the HR status of the second tumor. For women whose first breast tumors were HR negative, the risk of a contralateral primary tumor was statistically significantly higher than that for women whose first tumors were HR positive (SIR = 3.57, 95% CI = 3.38 to 3.78, AR = 18 per 10 000 PY), and it was associated with a much greater likelihood of an HR-negative second tumor (SIR for HR-positive second tumors = 1.94, 95% CI = 1.77 to 2.13, AR = 20 per 10 000 PY; SIR for HR-negative second tumors = 9.81, 95% CI = 9.00 to 10.7, AR = 24 per 10 000 PY). Women who were initially diagnosed with HR-negative tumors when younger than 30 years had greatly elevated risk of HR-negative contralateral tumors, compared with the general population (SIR = 169, 95% CI = 106 to 256, AR = 77 per 10 000 PY). Incidence rates for any contralateral primary cancer following an HR-negative or HR-positive tumor were higher in non-Hispanic blacks, Hispanics, and Asians or Pacific Islanders than in non-Hispanic whites.

CONCLUSIONS

Risk for contralateral second primary breast cancers varies substantially by HR status of the first tumor, age, and race and/or ethnicity. Women with HR-negative first tumors have nearly a 10-fold elevated risk of developing HR-negative second tumors, compared with the general population. These findings warrant intensive surveillance for second breast cancers in women with HR-negative tumors.

Subsequent malignant neoplasms in cancer survivors

In the past 3 decades, the number of cancer survivors in the United States has tripled, reaching approximately 10.7 million in 2004. Although cancer survivors now comprise about 3.5% of the population, subsequent malignancies among this high-risk group account for about 16% (or 1 in 6) of all cancer incidence. Multiple primary cancers can reflect the influence of antecedent cancer therapy, shared etiologic factors, environmental exposures, genetic susceptibility, lifestyle choices, other factors, and the combinations of effects, including gene-environment and gene-gene interactions. Survivors of individual types of primary cancers are at increased risk for distinctive types of subsequent neoplasms. Careful documentation of the magnitude and temporal patterns of these site-specific excess risks, as well as delineation of the contribution of treatment exposures and other factors, will facilitate the development of optimal follow-up plans. Management approaches should include patient education, screening, and prevention strategies. An improved understanding of those malignancies that are largely treatment-related will facilitate the formulation of customized therapeutic approaches for newly diagnosed cancer patients aimed at minimizing the risk of subsequent neoplasms and other late effects, without compromising cure rates.

Epidemiology of multiple primary cancers

Cancer patients have a 20% higher risk of new primary cancer compared with the general population. Approximately one third of cancer survivors aged >60 years were diagnosed more than once with another cancer. As the number of cancer survivors and of older people increases, occurrence of multiple primary cancers is also likely to increase. An increasing interest from epidemiologic and clinical perspectives seems logical. This chapter begins with the risk pattern of multiple cancers in the population of a developed country with high survival rates. Multiple cancers comprise two or more primary cancers occurring in an individual that originate in a primary site or tissue and that are neither an extension, nor a recurrence or metastasis. Studies of multiple cancers have been mainly conducted in population-based settings, and more recently in clinical trials and case control studies leading to further understanding of risk factors for the development of multiple primary cancers. These factors include an inherited predisposition to cancer; the usual carcinogenic or cancer-promoting aspects of lifestyle, hormonal, and environmental factors; treatment of the previous primary cancer; and increased surveillance of cancer survivors. Finally, implication on research strategies and clinical practice are discussed, covering the whole range of epidemiologic approach.

Soy isoflavones, estrogen therapy, and breast cancer risk: analysis and commentary

There has been considerable investigation of the potential for soyfoods to reduce risk of cancer, and in particular cancer of the breast. Most interest in this relationship is because soyfoods are essentially a unique dietary source of isoflavones, compounds which bind to estrogen receptors and exhibit weak estrogen-like effects under certain experimental conditions. In recent years the relationship between soyfoods and breast cancer has become controversial because of concerns – based mostly on in vitro and rodent data – that isoflavones may stimulate the growth of existing estrogen-sensitive breast tumors. This controversy carries considerable public health significance because of the increasing popularity of soyfoods and the commercial availability of isoflavone supplements. In this analysis and commentary we attempt to outline current concerns regarding the estrogen-like effects of isoflavones in the breast focusing primarily on the clinical trial data and place these concerns in the context of recent evidence regarding estrogen therapy use in postmenopausal women. Overall, there is little clinical evidence to suggest that isoflavones will increase breast cancer risk in healthy women or worsen the prognosis of breast cancer patients. Although relatively limited research has been conducted, and the clinical trials often involved small numbers of subjects, there is no evidence that isoflavone intake increases breast tissue density in pre- or postmenopausal women or increases breast cell proliferation in postmenopausal women with or without a history of breast cancer. The epidemiologic data are generally consistent with the clinical data, showing no indication of increased risk. Furthermore, these clinical and epidemiologic data are consistent with what appears to be a low overall breast cancer risk associated with pharmacologic unopposed estrogen exposure in postmenopausal women. While more research is required to definitively allay concerns, the existing data should provide some degree of assurance that isoflavone exposure at levels consistent with historical Asian soyfood intake does not result in adverse stimulatory effects on breast tissue.

MC1R variants associated susceptibility to basal cell carcinoma of skin: interaction with host factors and XRCC3 polymorphism

The variants within the human melanocortin 1 receptor (MC1R) gene are associated with an increased risk of different skin cancers. In this study, we genotyped by direct sequencing, 529 cases of basal cell carcinoma of the skin (BCC) and 533 healthy controls for polymorphisms in the entire MC1R gene. In addition to 10 common polymorphisms, we detected 23 rare variants in the gene. The presence of any nonsynonymous MC1R variant was associated with an increased risk in the carriers (odds ratio OR 1.66, 95% confidence interval CI 1.28-2.14) corresponding to a population attributable fraction of about 27%. The odds ratio for the risk in the carriers of 2 MC1R variants was 2.69 (95% CI 1.77-4.08). The risk of BCC in the carriers of MC1R variants with fair complexion was almost twice as much as in the corresponding noncarriers. The carriers of the R163Q variant with a medium skin complexion were at a 3-fold higher risk than the noncarrier counterparts. The interaction, of effect on the BCC risk, between the MC1R variants and types of skin response to sun exposure was greater than multiplicative. We also observed a multiplicative interaction of risk due to the MC1R variants and the common allele (high risk) of the T241M polymorphism in the XRCC3 gene. Our data confirmed the status of the nonsynonymous MC1R variants as independent genetic risk factors for BCC. However, the mechanism through which the variants influence the risk likely involves complex interactions with other genetic and host risk factors.

Modification of risk for subsequent cancer after female breast cancer by a family history of breast cancer

An increased risk of second primary cancers may depend on many reasons, including therapy for the first cancer and heritable causation. Population level data are not available exploring the risks of subsequent cancers after breast cancer considering a familial history of breast cancers. We used the nation-wide Swedish Family-Cancer Database to investigate such risks, based on 43,398 first invasive female breast cancers. Standardized incidence ratios (SIRs) were calculated for the second cancer after breast cancer using rates for first cancer as a reference. Many cancers at discordant sites were increased after breast cancer. SIRs for subsequent neoplasms in women who had a family history of breast cancer were increased for ovarian (2.0) and endometrial (1.8) cancers and for acute lymphoid leukemia (12.7) and myelofibrosis (9.4). The data suggest that the familial aggregation of breast and endometrial cancers may be explained by yet unidentified heritable causes. The remarkably high risks for second acute lymphoid leukemia and myelofibrosis, both characterized by chromosomal aberrations, in women with a family history of breast cancer may signal heritable defects in the ability to process DNA damage caused by ionizing radiation and chemotherapy.