Response to radiation therapy and prognosis in breast cancer patients with BRCA1 and BRCA2 mutations

A systematic review exploring the role of modern radiation for the treatment of Hereditary or Familial Breast Cancer

The diagnosis of hereditary or familial breast cancers influences the locoregional approach to breast cancer, with most patients undergoing mastectomy to avoid or minimize the use of adjuvant radiation therapy. We evaluated the current literature about known high- and moderate-penetrance genes and studied their impact on local control, toxicities, and contralateral breast cancers after adjuvant radiation therapy. The aim is to encourage the safe use of adjuvant radiation therapy when indicated in concordance with the updated guidelines.

Liquid biopsy in NSCLC: a new challenge in radiation therapy

Lung cancer is the most common cancer and the leading cause of cancer mortality worldwide. To date, tissue biopsy has been the gold standard for the diagnosis and the identification of specific molecular mutations, to guide choice of therapy. However, this procedure has several limitations. Liquid biopsy could represent a solution to the intrinsic limits of traditional biopsy. It can detect cancer markers such as circulating tumor DNA or RNA (ctDNA, ctRNA), and circulating tumor cells, in plasma, serum or other biological fluids. This procedure is minimally invasive, reproducible and can be used repeatedly. The main clinical applications of liquid biopsy in non-small cell lung cancer (NSCLC) patients are the early diagnosis, stratification of the risk of relapse, identification of mutations to guide application of targeted therapy and the evaluation of the minimum residual disease. In this review, the current role of liquid biopsy and associated markers in the management of NSCLC patients was analyzed, with emphasis on ctDNA and CTCs, and radiotherapy.

Local Treatment of Triple-Negative Breast Cancer

ABSTRACT

Triple-negative breast cancer, compared with other molecular subtypes, poses particular challenges for optimizing the timing and the extent of locoregional treatments. In the past, the combination of increased rates of both locoregional and distant recurrences led to a preference of radical surgery and extensive radiation therapy; however, since the introduction of more effective chemotherapy, a sharp de-escalation in the extent of locoregional treatments followed. Current evidence confirms that less aggressive surgery in combination with tailored radiation therapy offers improved oncological outcomes combined with better quality of life. However, further research is required to optimize locoregional treatments, considering the significant heterogeneity in biological behavior and tumor response to systemic treatments.

Developing more sensitive genomic approaches to detect radioresponse in precision radiation oncology: From tissue DNA analysis to circulating tumor DNA

Despite the common application and considerable efforts to achieve precision radiotherapy (RT) in several types of cancer, RT has not yet entered the era of precision medicine; the ability to predict radiosensitivity and treatment responses in tumors and normal tissues is lacking. Therefore, development of genome-based methods for individual prognosis in radiation oncology is urgently required. Traditional DNA sequencing requires tissue samples collected during invasive operations; therefore, repeated tests are nearly impossible. Intra- and inter-tumoral heterogeneity may undermine the predictive power of a single assay from tumor samples. In contrast, analysis of circulating tumor DNA (ctDNA) allows for non-invasive and near real-time sampling of tumors. By investigating the genetic composition of tumors and monitoring dynamic changes during treatment, ctDNA analysis may potentially be clinically valuable in prediction of treatment responses prior to RT, surveillance of responses during RT, and evaluation of residual disease following RT. As a biomarker for RT response, ctDNA profiling may guide personalized treatments. In this review, we will discuss approaches of tissue DNA sequencing and ctDNA detection and summarize their clinical applications in both traditional RT and in combination with immunotherapy.

The role of BRCA1/2 in hereditary and familial breast and ovarian cancers

BACKGROUND

BRCA1/2 pathogenic variants have become associated with familial breast and ovarian cancers, and hereditary cancer-predisposition syndrome. With advances in molecular biology, BRCA profiling facilitates early diagnosis and the implementation of preventive and therapeutic strategies. The genes exhibit variable prevalence among different individuals and moderate interpretation complexity. BRCA deficiency is instrumental in cancer development, affects therapeutic options and is instrumental in drug resistance. In addition, BRCA1/2 profile is diverse across different groups and has been associated with the "founder effect" in certain populations.

METHODS

In this review, we aim to detail the spectrum of BRCA1/2 variants and their associated risk estimates.

RESULTS

The relationship between BRCA1/2 and hereditary and familial cancers is indisputable, yet BRCA screening methods are beset with limitations and lack clinical confidence.

CONCLUSION

This review emphasizes the importance of screening BRCA genetics, in addition to their clinical utility. Furthermore, founder variants are anticipated in the Saudi population.

Is breast-conserving therapy adequate in BRCA 1/2 mutation carriers? The radiation oncologist's point of view

Breast conserving therapy (BCT) is currently a recognized alternative to mastectomy for early BC patients. However, the therapeutic index of BCT was considered controversial for decades in BRCA1/2 mutation carriers. The aim of the present review was to investigate the outcome of mutation carriers undergoing BCT regarding local and distant endpoints. A short review was performed from the point of view of the radiation oncologist. Only retrospective data were available regarding local outcome assessment. They generated conflicting results. In studies with limited follow-up, BCT did not increase the risk of local recurrence in BRCA1/2 mutation carriers versus non-carriers. Conversely, some studies with longer follow-up supported that local relapse was increased in mutation carriers. Yet, according to some publications, their long-term risk of ipsilateral recurrence post-BCT was not different from general population cohorts. Besides, overall and metastasis-free survivals were the same after BCT regardless of the BRCA1/2 mutation status. Similar survival rates were also reported when BCT and mastectomy were compared in mutation carriers. Regarding acute or late toxicity, normal rates were reported in BRCA mutation carriers after breast radiotherapy. The BRCA1/2 mutation does not seem to widely alter the therapeutic index (efficacy/toxicity ratio) of modern adjuvant breast irradiation. Although the long term equivalence of BCT/mastectomy on local control is still not clearly recognised, BCT can be considered an adequate option for BRCA1/2 mutation carriers. This review highlights that BCT is a reasonable option for BRCA1/2 mutation carriers however litterature is controversial concerning long-term local outcome and results of a large prospective cohort are needed.

[Cost-effectiveness of risk-reducing salpingo-oophorectomy in cases of BRCA1 gene mutation in Colombia]

OBJECTIVE

To assess the usefulness of risk reduction salpingo-oophorectomy in cases with mutation of the BRCA1 gene in Colombia.

MATERIAL AND METHODS

Cost-effectiveness analysis in which three processes are incorporated: a. Patients with screening tests for breast and ovarian cancer. b. Risk reduction surgery in the fallopian tubes and ovaries c. Reductive surgery in the fallopian tubes and ovaries with bilateral mastectomy. The outcome is evaluated as the gain in years of survival.

RESULTS

The cohort with risk reduction surgery in the fallopian tubes and ovaries and bilateral mastectomy is the one with the highest gain with 13 years, while the risk reduction surgery in the fallopian tubes and ovaries gain 4.95 years with respect to the follow-up group.

CONCLUSIONS

The three options evaluated are acceptable, but of them the one with the greatest gain in survival is the combination of risk-reducing surgery in the fallopian tubes and ovaries with bilateral mastectomy.

BRCA mutations and survival in breast cancer: an updated systematic review and meta-analysis

BRCA mutations occur frequently in breast cancer (BC), but their prognostic impact on outcomes of BC has not been determined. We conducted an updated meta-analysis on the association between BRCA mutations and survival in patients with BC. Electronic databases were searched. The primary outcome measure was overall survival (OS), and the secondary outcome measures included breast cancer-specific survival (BCSS) and event-free survival (EFS). Hazard ratios (HR) and 95% confidence interval (CI) were abstracted and pooled with random-effect modeling. Data from 297, 402 patients with BC were pooled from 34 studies. The median prevalence rates of BRCA1 and BRCA2 mutations were 14.5% and 8.3%, respectively. BRCA mutations were associated with worse OS (BRCA1: HR = 1.69, 95% CI, 1.35 to 2.12, p < 0.001; BRCA2: HR = 1.50, 95% CI 1.03 to 2.19, p = 0.034). However, this did not translate into poor BCSS (BRCA1: HR = 1.14, 95% CI, 0.81 to 1.16, p = 0.448; BRCA2: HR = 1.16; 95% CI 0.82 to 1.66, p = 0.401) or EFS (BRCA1: HR = 1.10, 95% CI, 0.86 to 1.41, p = 0.438; BRCA2: HR= 1.09; 95% CI 0.81 to 1.47, p = 0.558). Several studies analyzed BRCA1 and BRCA2 mutations together and found no impact on OS (HR = 1.21; 95% CI, 0.73 to 2.00, p = 0.454) or EFS (HR = 0.94; 95% CI, 0.60 to 1.48, p = 0.787). BRCA1 and BRCA2 mutations were associated with poor OS in patients with BC, but had no significant impact on BCSS or EFS. An improved survival was observed in BC patients who had BRCA1 mutation and treated with endocrinotherapy. The results may have therapeutic and prognostic implications important for BRCA mutation carriers with BC.

Assessment of the prognostic role of a 94-single nucleotide polymorphisms risk score in early breast cancer in the SIGNAL/PHARE prospective cohort: no correlation with clinico-pathological characteristics and outcomes

Background

Genome-wide association studies (GWAS) have to date identified 94 genetic variants (single nucleotide polymorphisms (SNPs)) associated with risk of developing breast cancer. A score based on the combined effect of the 94 risk alleles can be calculated to measure the global risk of breast cancer. We aimed to test the hypothesis that the 94-SNP-based risk score is associated with clinico-pathological characteristics, breast cancer subtypes and outcomes in early breast cancer.

Methods

A 94-SNP risk score was calculated in 8703 patients in the PHARE and SIGNAL prospective case cohorts. This score is the total number of inherited risk alleles based on 94 selected SNPs. Clinical data and outcomes were prospectively registered. Genotyping was obtained from a GWAS.

Results

The median 94-SNP risk score in 8703 patients with early breast cancer was 77.5 (range: 58.1–97.6). The risk score was not associated with usual prognostic and predictive factors (age; tumor, node, metastasis (TNM) status; Scarff-Bloom-Richardson grade; inflammatory features; estrogen receptor status; progesterone receptor status; human epidermal growth factor receptor 2 (HER2) status) and did not correlate with breast cancer subtypes. The 94-SNP risk score did not predict outcomes represented by overall survival or disease-free survival.

Conclusions

In a prospective case cohort of 8703 patients, a risk score based on 94 SNPs was not associated with breast cancer characteristics, cancer subtypes, or patients’ outcomes. If we hypothesize that prognosis and subtypes of breast cancer are determined by constitutional genetic factors, our results suggest that a score based on breast cancer risk-associated SNPs is not associated with prognosis.

Trial registration

PHARE cohort: NCT00381901, Sept. 26, 2006 – SIGNAL cohort: INCa RECF1098, Jan. 28, 2009

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-017-0888-4) contains supplementary material, which is available to authorized users.

Effect of BRCA2 mutation on familial breast cancer survival: A systematic review and meta-analysis

Reports of BRCA2 genetic mutations on the prognosis of familial breast cancer (BC) patients have been contradictory. True difference in survival, if it exists, would have important implications for genetic counseling and in treatment of hereditary BC. The purpose of this study was to compare overall survival rate (OSR) among BRCA2 mutation carriers, non-carriers and sporadic BC patients. We searched the PUBMED and EMBASE databases and retrieved 4529 articles using keywords that included breast cancer, BRCA, prognosis and survival. Nine articles were selected for systematic review and among them 6 were included in our meta-analysis. We used the fixed and random effect models to calculate the summary odds ratio (OR) and corresponding 95% confidence interval (CI). BRCA2 mutation carriers had significantly higher long-term OSR than non-carriers (OR=0.69 [95% CI=0.5-0.95]), while both short-term and long-term OSR of BRCA2 mutation carriers did not differ from those of patients with sporadic disease (OR=1.11 [95% CI=0.74-1.65]; 0.85 [95% CI=0.38-1.94], respectively). For BC-specific survival rate (BCSSR), BRCA2 mutation carriers had a similar BCSSR to the non-carriers (OR=0.61 [95% CI=0.28-1.34]). There was no significant difference in disease-free survival (DFS) between BRCA2 mutation carriers and patients with sporadic disease. Our results suggest that BRCA2 mutation increases long-term OSR in hereditary BC, which reminds us a new prospect of management of the disease.

Radiation therapy in the locoregional treatment of triple-negative breast cancer

This Review assesses the relevant data and controversies regarding the use of radiotherapy for, and locoregional management of, women with triple-negative breast cancer (TNBC). In view of the strong association between BRCA1 and TNBC, knowledge of baseline mutation status can be useful to guide locoregional treatment decisions. TNBC is not a contraindication for breast conservation therapy because data suggest increased locoregional recurrence risks (relative to luminal subtypes) with breast conservation therapy or mastectomy. Although a boost to the tumour bed should routinely be considered after whole breast radiation therapy, TNBC should not be the sole indication for post-mastectomy radiation, and accelerated delivery methods for TNBC should be offered on clinical trials. Preliminary data implying a relative radioresistance for TNBC do not imply radiation omission because radiation provides an absolute locoregional risk reduction. At present, the integration of subtypes in locoregional management decisions is still in its infancy. Until level 1 data supporting treatment decisions based on subtypes are available, standard locoregional management principles should be adhered to.

BRCA1/2 Mutation-associated Breast Cancer, Wide Local Excision and Radiotherapy or Unilateral Mastectomy: A Systematic Review

AIMS

BRCA1/2 mutation carriers show reduced apoptotic response to ionising radiation leading to recent debate about the safety of wide local excision and radiotherapy. The aim of the current study was to determine if BRCA1/2 mutation carriers with breast cancer undergoing wide local excision and radiotherapy show increased ipsilateral and contralateral breast tumour recurrence and reduced survival compared with unilateral mastectomy.

MATERIALS AND METHODS

Following a detailed literature search, the methodology, populations, biases and outcomes of ipsilateral breast tumour recurrence, contralateral breast tumour recurrence and survival were evaluated for 25 articles.

RESULTS

No differences in outcomes were found between wide local excision and mastectomy. BRCA1/2 mutation status was predictive of contralateral breast cancer only. Radiotherapy reduces the risk of ipsilateral recurrence and confers no increase in contralateral recurrence.

CONCLUSION

BRCA1/2 mutation status does not preclude treatment with wide local excision and radiotherapy. Given the retrospective studies with inherent flaws and small patient numbers, further large prospective trials are required.

Worse breast cancer prognosis of BRCA1/BRCA2 mutation carriers: what's the evidence? A systematic review with meta-analysis

Objective

Conflicting conclusions have been published regarding breast cancer survival of BRCA1/2 mutation carriers. Here we provide an evidence-based systematic literature review.

Methods

Eligible publications were observational studies assessing the survival of breast cancer patients carrying a BRCA1/2 mutation compared to non-carriers or the general breast cancer population. We performed meta-analyses and best-evidence syntheses for survival outcomes taking into account study quality assessed by selection bias, misclassification bias and confounding.

Results

Sixty-six relevant studies were identified. Moderate evidence for a worse unadjusted recurrence-free survival for BRCA1 mutation carriers was found. For BRCA1 and BRCA2 there was a tendency towards a worse breast cancer-specific and overall survival, however, results were heterogeneous and the evidence was judged to be indecisive. Surprisingly, only 8 studies considered adjuvant treatment as a confounder or effect modifier while only two studies took prophylactic surgery into account. Adjustment for tumour characteristics tended to shift the observed risk estimates towards a relatively more favourable survival.

Conclusions

In contrast to currently held beliefs of some oncologists, current evidence does not support worse breast cancer survival of BRCA1/2 mutation carriers in the adjuvant setting; differences if any are likely to be small. More well-designed studies are awaited.

Clinical relevance of normal and tumour cell radiosensitivity in BRCA1/BRCA2 mutation carriers: a review

Women harbouring BRCA1/2 mutations are known to be at higher lifetime risk of developing breast cancer than non-carriers. Compared to mastectomy, conservative surgery is also associated, in this patient population, with a higher probability to developing recurrent ipsilateral breast cancer following primary treatment. To reduce these risks, the management of BRCA1/2 - associated cancers has therefore focused on optimal prophylactic and therapeutic interventions at the time of diagnosis. In a recent past, comparative analyses of radiosensitivity levels have been carried out in murine embryos harbouring BRCA1/2 gene mutation and in non-carriers. The fact that a number of these experimental data are in favour of higher radiosensitivity levels in carriers of germline mutations leads to concern regarding the potential consequences of exposure to radiation, especially in terms of excessive toxicity in normal tissues and radiation-induced malignancies. The objective of this review is to determine whether or not the potentially higher radiosensitivity of normal and tumour cells has a clinical relevance in BRCA1/2 mutations carriers in terms of disease control, acute and late adverse events, and tumourigenesis.

The influence of BRCA1/BRCA2 mutations on toxicity related to chemotherapy and radiotherapy in early breast cancer patients

OBJECTIVE

The presence of BRCA gene mutation and low expressions of BRCA proteins are associated with a greater sensitivity of tumor cells to ionizing radiation and to cytostatics damaging the DNA of the cells. The purpose of this study was to estimate the rate of adverse events in BRCA1/2-associated breast cancer patients receiving anthracycline-based chemotherapy compared to patients without mutation. The authors also compared radiotherapy toxicity in these 2 groups.

METHODS

The analysis included 270 early-stage breast cancer patients treated between 2006 and 2012. All patients were examined for the presence of BRCA1/2 mutations.

RESULTS

BRCA mutation was detected in 41 (15%) patients. Toxicity grade 3, especially nausea and vomiting, was observed more often in noncarriers (7 vs. 13%, p = 0.0008). Neutropenia was detected more frequently in patients with BRCA1/2 mutation (32 vs. 10%), but only after 1 cycle of chemotherapy (p = 0.0007). There was increased radiation toxicity in BRCA1/2 patients who underwent mastectomy and neoadjuvant chemotherapy (p = 0.016).

CONCLUSIONS

BRCA1/2 mutation carriers seemed to be more at risk of neutropenia after the first cycle of the treatment. In terms of other side effects, there was a lack of increased toxicity in this group. Mastectomy and neoadjuvant chemotherapy were risk factors for radiation toxicity in mutation carriers.

The Role of PARP Inhibitors in the Treatment of Gynecologic Malignancies

Gynecologic malignancies annually account for over 91,000 new cancer cases and approximately 28,000 deaths in the United States. Although there have been advancements in cytotoxic chemotherapies, there has not been significant improvement in overall survival in these patients. While targeted therapies have shown some benefit in many solid tumors, further development of these agents is needed for the treatment of gynecologic malignancies. Poly(ADP-ribose) polymerase (PARP) catalyzes the polyADP-ribosylation of proteins involved in DNA repair. Inhibitors of PARP were originally developed for cancers with homologous recombination deficiencies, such as those harboring mutations in BRCA1 or BRCA2 genes. However, pre-clinical research and clinical trials have suggested that the activity of PARP inhibitors is not limited to those with BRCA mutations. PARP inhibitors may have activity in cancers deficient in other DNA repair genes, signaling pathways that mitigate DNA repair, or in combination with DNA-damaging agents independent of DNA repair dysfunction. Currently there are seven different PARP inhibitors in clinical development for cancer. While there has been promising clinical activity for some of these agents, there are still significant unanswered questions regarding their use. Going forward, specific questions that must be answered include timing of therapy, use in combination with cytotoxic agents or as single-agent maintenance therapy, and whether there is a predictive biomarker that can be used with PARP inhibition. Even with large strides in the treatment of many gynecologic malignancies in recent years, it is imperative that we develop newer agents and methods to identify patients that may benefit from these compounds. The focus of this review will be on pre-clinical data, current clinical trials, and the future of PARP inhibitors in the treatment of ovarian, endometrial, and cervical cancer.

Acute skin toxicity in Korean breast cancer patients carrying BRCA mutations

PURPOSE

In contrast to in vitro studies, most clinical trials testing the radiosensitivity of BRCA (Breast cancer susceptibility gene) mutations do not find a correlation between BRCA status and enhanced radiosensitivity. These trials include different ethnicities, and there is a lack of clinical data on BRCA1/2 mutation carriers and radiosensitivity in non-Caucasian patients. The goal of this study was to investigate acute skin toxicity, as a part of radiosensitivity, in breast cancer patients with BRCA1/2 mutations.

MATERIAL AND METHODS

BRCA mutation analysis was performed for 213 patients who underwent breast-conserving therapy using radiotherapy. Skin toxicity was scored according to the Radiation Therapy Oncology Group (RTOG) criteria during treatment and during one-month follow-up after radiation therapy.

RESULTS

Forty-six patients had BRCA1/2 mutations and 57 patients showed higher than grade 2 (RTOG) skin toxicity. In multivariate analysis, significant associations were found between mean breast volume and acute skin toxicity. BRCA mutation status, however, failed to show a significant correlation.

CONCLUSIONS

Our results indicate that carriers of BRCA1/2 mutations among non-Caucasian breast cancer patients showed no enhancement in radiation sensitivity. Multiple genetic markers may be correlated with normal tissue responses after radiotherapy. Further studies are needed to identify genetic predispositions to normal tissue responses after radiotherapy.

Contralateral breast cancer after radiotherapy among BRCA1 and BRCA2 mutation carriers: a WECARE study report

BACKGROUND

Women with germline BRCA1 or BRCA2 (BRCA1/BRCA2) mutations are at very high risk of developing breast cancer, including asynchronous contralateral breast cancer (CBC). BRCA1/BRCA2 genes help maintain genome stability and assist in DNA repair. We examined whether the risk of CBC associated with radiation treatment was higher among women with germline BRCA1/BRCA2 mutations than among non-carriers.

METHODS

A population-based, nested case-control study was conducted within a cohort of 52,536 survivors of unilateral breast cancer (UBC). Cases were 603 women with CBC and controls were 1199 women with UBC individually matched on age at diagnosis, race, year of first diagnosis and cancer registry. All women were tested for BRCA1 and BRCA2 mutations. Radiation absorbed dose from the initial radiotherapy (RT) to the CBC location within the contralateral breast was reconstructed from measurements in a tissue-equivalent phantom and details available in the therapy records.

FINDINGS

Among women treated with radiation, the mean radiation dose was 1.1 Gy (range = 0.02-6.2 Gy). Risk of developing CBC was elevated among women who carried a deleterious BRCA1/BRCA2 mutation (rate ratio, RR = 4.5, confidence interval, CI = 3.0-6.8), and also among those treated with RT (RR = 1.2, CI = 1.0-1.6). However, among mutation carriers, an incremental increase in risk associated with radiation dose was not statistically significant.

INTERPRETATION

Multiplicative interaction of RT with mutation status would be reflected by a larger association of RT with CBC among carriers than among non-carriers, but this was not apparent. Accordingly, there was no clear indication that carriers of deleterious BRCA/BRCA2 mutations were more susceptible to the carcinogenic effects of radiation than non-carriers. These findings are reassuring and have important clinical implications for treatment decisions and the clinical management of patients harbouring deleterious BRCA1/BRCA2 mutations.

FUNDING

All work associated with this study was supported by the U.S. National Cancer Institute [R01CA097397, U01CA083178].

Identifying and exploiting defects in the Fanconi anemia/BRCA pathway in oncology

Defects in components of DNA repair pathways are responsible for numerous hereditary cancer syndromes and are also common in many sporadic malignancies. Inherited mutations in the breast cancer susceptibility genes BRCA1 and BRCA2 or components of the Fanconi anemia (FA) complex incite genomic instability and predispose to malignancy. The products of the BRCA and FA genes participate in a conserved DNA damage repair pathway that is responsible for repairing interstrand crosslinks and double-strand DNA breaks by homologous recombination. While the genetic instability resulting from FA/BRCA dysfunction contributes to cancer pathogenesis, deficiency of these genes also lends to therapeutic exploitation. Crosslinking agents and ionizing radiation induce damage in cancer cells that requires the FA/BRCA pathway to be resolved; thus cancers that are deficient in BRCA1, BRCA2, or any other component of the FA/BRCA pathway are hypersensitive to these agents. Moreover, emerging synthetic lethal strategies offer opportunities to selectively target cancer cells with defects in homologous recombination. Conversely, enhanced activity of the FA/BRCA pathway is responsible for acquired resistance to specific therapeutic agents, suggesting that both dysfunction and hyperfunction of the FA/BRCA repair machinery are rational targets for cancer therapy. Selection of specific cytotoxic agents based on repair capacity may improve responses and enable personalized cytotoxic chemotherapy. This article reviews the FA/BRCA pathway and current approaches to identify deficiencies within it, discusses synthetic lethality and enhanced repair capacity as causes of therapeutic hypersensitivity and resistance, respectively, and highlights recent studies that have linked FA/BRCA pathway function with therapeutic efficacy.

A bioinformatics filtering strategy for identifying radiation response biomarker candidates

The number of biomarker candidates is often much larger than the number of clinical patient data points available, which motivates the use of a rational candidate variable filtering methodology. The goal of this paper is to apply such a bioinformatics filtering process to isolate a modest number (<10) of key interacting genes and their associated single nucleotide polymorphisms involved in radiation response, and to ultimately serve as a basis for using clinical datasets to identify new biomarkers. In step 1, we surveyed the literature on genetic and protein correlates to radiation response, in vivo or in vitro, across cellular, animal, and human studies. In step 2, we analyzed two publicly available microarray datasets and identified genes in which mRNA expression changed in response to radiation. Combining results from Step 1 and Step 2, we identified 20 genes that were common to all three sources. As a final step, a curated database of protein interactions was used to generate the most statistically reliable protein interaction network among any subset of the 20 genes resulting from Steps 1 and 2, resulting in identification of a small, tightly interacting network with 7 out of 20 input genes. We further ranked the genes in terms of likely importance, based on their location within the network using a graph-based scoring function. The resulting core interacting network provides an attractive set of genes likely to be important to radiation response.

Breast cancer prognosis in BRCA1 and BRCA2 mutation carriers: an International Prospective Breast Cancer Family Registry population-based cohort study

PURPOSE

To compare breast cancer prognosis in BRCA1 and BRCA2 mutation carriers with that in patients with sporadic disease.

PATIENTS AND METHODS

An international population-based cohort study was conducted in Canada, the United States, and Australia of 3,220 women with incident breast cancer diagnosed between 1995 and 2000 and observed prospectively. Ninety-three had BRCA1 mutations; 71, BRCA2 mutations; one, both mutations; 1,550, sporadic breast cancer; and 1,505, familial breast cancer (without known BRCA1 or BRCA2 mutation). Distant recurrence and death were analyzed.

RESULTS

Mean age at diagnosis was 45.3 years; mean follow-up was 7.9 years. Risks of distant recurrence and death did not differ significantly between BRCA1 mutation carriers and those with sporadic disease in univariable and multivariable analyses. Risk of distant recurrence was higher for BRCA2 mutation carriers compared with those with sporadic disease in univariable analysis (hazard ratio [HR], 1.63; 95% CI, 1.02 to 2.60; P = .04). Risk of death was also higher in BRCA2 carriers in univariable analysis (HR, 1.81; 95% CI, 1.15 to 2.86; P = .01). After adjustment for age, tumor stage and grade, nodal status, hormone receptors, and year of diagnosis, no differences were observed for distant recurrence (HR, 1.00; 95% CI, 0.62 to 1.61; P = 1.00) or death (HR, 1.12; 95% CI, 0.70 to 1.79; P = .64).

CONCLUSION

Outcomes of BRCA1 mutation carriers were similar to those of patients with sporadic breast cancer. Worse outcomes in BRCA2 mutation carriers in univariable analysis seem to reflect the presence of more adverse tumor characteristics in these carriers. Similar outcomes were identified in BRCA2 carriers and those with sporadic disease in multivariable analyses.

Prophylactic and Therapeutic Breast Conservation in BRCA1/2 Mutation Carriers

Breast-conserving therapy (BCT) for sporadic breast cancer has been widely accepted by surgeons and patients alike. While BCT is associated with a higher risk of ipsilateral breast tumor recurrence (IBTR), it has not been shown to decrease overall survival (OS) in comparison with mastectomy. Many women with a BRCA1/2 mutation opt for mastectomy instead of breast-conserving measures at the time of a breast cancer diagnosis. In some cases, this is due to fear of aggressive disease, but to date, there have been no studies offering strong evidence that breast conservation should not be offered to these women. BRCA1/2-associated breast cancer has not been found to be more aggressive or resistant to treatment than comparable sporadic tumors, and no study has shown an actual survival advantage for mastectomy in appropriately treated affected mutation carriers. This paper reviews the available literature for breast conservation and surgical decision making in BRCA1/2 mutation carriers.

Risk-reducing strategies for women carrying BRCA1/2 mutations with a focus on prophylactic surgery

Background

Women who have inherited mutations in the BRCA1 or BRCA2 genes have substantially elevated risks of breast and ovarian cancer. Mutation carriers have various options, including extensive and regular surveillance, chemoprevention and risk-reducing surgery. The aim of this review is to provide an up-to-date analysis and to subsequently summarise the available literature in relation to risk-reducing strategies, with a keen focus on prophylactic surgery.

Methods

The literature review is facilitated by Medline and PubMed databases. The cross-referencing of the obtained articles was used to identify other relevant studies.

Results

Prophylactic surgery (bilateral mastectomy, bilateral salpingo-oophorectomy or a combination of both procedures) has proved to be the most effective risk-reducing strategy. There are no randomised controlled trials able to demonstrate the potential benefits or harms of prophylactic surgery; therefore, the evidence has been derived from retrospective and short follow-up prospective studies, in addition to hypothetical mathematical models.

Based on the current knowledge, it is reasonable to recommend prophylactic oophorectomy for BRCA1 or BRCA2 mutation carriers when childbearing is completed in order to reduce the risk of developing breast and ovarian cancer. In addition, women should be offered the options of rigorous breast surveillance, chemoprevention with anti-oestrogens--especially for carriers of BRCA2--or bilateral prophylactic mastectomy.

Conclusion

The selection of the most appropriate risk-reducing strategy is not a straightforward task. The impact of risk-reducing strategies on cancer risk, survival, and overall quality of life are the key criteria considered for decision-making. Notably, various other factors should be taken into consideration when evaluating individual mutation carriers' individual circumstances, namely woman's age, morbidity, type of mutation, and individual preferences and expectations.

Although prospective randomised controlled trials concerned with examining the various interventions in relation to the woman's age and type of mutation are needed, randomisation is extremely difficult and rather deemed unethical given the current available evidence from retrospective studies.

Hereditary breast and ovarian cancer due to mutations in BRCA1 and BRCA2

Hereditary breast and ovarian cancer due to mutations in the BRCA1 and BRCA2 genes is the most common cause of hereditary forms of both breast and ovarian cancer. The overall prevalence of BRCA1/2 mutations is estimated to be from 1 in 400 to 1 in 800 with a higher prevalence in the Ashkenazi Jewish population (1 in 40). Estimates of penetrance (cancer risk) vary considerably depending on the context in which they were derived and have been shown to vary within families with the same BRCA1/2 mutation. This suggests there is no exact risk estimate that can be applied to all individuals with a BRCA1/2 mutation. The likelihood of harboring a BRCA1 or BRCA2 mutation is dependent on one's personal and/or family history of cancer and can be estimated using various mutation probability models. For those individuals who have a BRCA1 or BRCA2 mutation, several screening and primary prevention options have been suggested, including prophylactic surgery and chemoprevention. Once a BRCA1 or BRCA2 mutation has been identified in a family, testing of at-risk relatives can identify those family members who also have the familial mutation and thus need increased surveillance and early intervention when a cancer is diagnosed.

Germline genetic variation, cancer outcome, and pharmacogenetics

Studies of the role of germline or inherited genetic variation on cancer outcome can fall into three distinct categories. First, the impact of highly penetrant but lowly prevalent mutations of germline DNA on cancer prognosis has been studied extensively for BRCA1 and BRCA2 mutations as well as mutations related to hereditary nonpolyposis colorectal cancer syndrome. These mainly modest-sized analyses have produced conflicting results. Although some associations have been observed, they may not be independent of other known clinical or molecular prognostic factors. Second, the impact of germline polymorphisms on cancer prognosis is a burgeoning field of research. However, a deeper understanding of potentially confounding somatic changes and larger multi-institutional, multistage studies may be needed before consistent results are seen. Third, research examining the impact of germline genetic variation on differential treatment response or toxicity (pharmacogenetics) has produced some proof-of-principle results. Putative germline pharmacogenetic predictors of outcome include DPYD polymorphisms and fluorouracil toxicity, UGT1A1 variation and irinotecan toxicity, and CYP2D6 polymorphisms and tamoxifen efficacy, with emerging data on predictors of molecularly targeted or biologic drugs. Here we review data pertaining to these germline outcome and germline toxicity relationships.

Increased chromosomal radiosensitivity in women carrying BRCA1/BRCA2 mutations assessed with the G2 assay

PURPOSE

Several in vitro studies suggest that BRCA1 and BRCA2 mutation carriers present increased sensitivity to ionizing radiation. Different assays for the assessment of deoxyribonucleic acid double-strand break repair capacity have been used, but results are rather inconsistent. Given the concerns about the possible risks of breast screening with mammography in mutation carrier women and the potentially damaging effects of radiotherapy, the purpose of this study was to further investigate the radiosensitivity of this population.

METHODS AND MATERIALS

The G2 chromosomal radiosensitivity assay was used to assess chromosomal breaks in lymphocyte cultures after exposure to 1 Gy. A group of familiar breast cancer patients carrying a mutation in the BRCA1 or BRCA2 gene (n = 15) and a group of healthy mutation carriers (n = 5) were investigated and compared with a reference group of healthy women carrying no mutation (n = 21).

RESULTS

BRCA1 and BRCA2 mutation carriers had a significantly higher number of mean chromatid breaks per cell (p = 0.006) and a higher maximum number of breaks (p = 0.0001) as compared with their matched controls. Both healthy carriers and carriers with a cancer history were more radiosensitive than controls (p = 0.002 and p = 0.025, respectively). Age was not associated with increased radiosensitivity (p = 0.868).

CONCLUSIONS

Our results indicate that BRCA1 and BRCA2 mutation carriers show enhanced radiosensitivity, presumably because of the involvement of the BRCA genes in deoxyribonucleic acid repair and cell cycle control mechanisms.

Genetic variants and normal tissue toxicity after radiotherapy: a systematic review

During the last decade, nearly 60 studies have addressed possible associations between various genetic sequence alterations and risk of adverse reactions after radiotherapy. We report here an overview of these studies with information on the genetic variants, tumour type, number of patients included, the endpoint studied, the mechanism(s) by which the candidate genes are involved in the pathogenesis of normal tissue toxicity, and odds ratios (ORs) for candidate variants. Though many positive results have been reported, inconsistent findings and non-replication of previous results have frequently occurred. This can presumably be attributed to certain methodological shortcomings including lack of statistical power to detect small effect sizes. Based on theoretical considerations and experiences from other scientific fields, we discuss how future studies should be designed in order to successfully unravel the genetics of normal tissue radiosensitivity. We propose a model of the allelic architecture that may underlie differences in normal tissue radiosensitivity. Genome wide association studies have proven a powerful tool to identify novel loci that affect various phenotypes. Nonetheless, genome wide association studies are extremely demanding in terms of sample size. Furthermore, certain limitations still relate to this kind of studies, emphasizing the need for international consortia such as the ESTRO GENEPI.

Survival in Norwegian BRCA1 mutation carriers with breast cancer

Several studies of survival in women with BRCA1 mutations have shown either reduced survival or no difference compared to controls. Programmes for early detection and treatment of inherited breast cancer, have failed to demonstrate a significant improvement in survival in BRCA1 mutation carriers.

One hundred and sixty-seven women with disease-associated germline BRCA1 mutations and breast cancer from 1980 to 2001 were identified. Tumour characteristics, treatment given and survival were recorded. A control group comprising three hundred and four women matched for age, time of diagnosis and stage were used to compare survival.

BRCA1 mutation carriers were found to have a poorer prognosis, which could be explained by neither the mode of surgical treatment nor the use of adjuvant chemotherapy. BRCA1 mutation carriers with node negative breast cancer had worse overall survival than controls.

Our findings confirm the serious prognosis of BRCA1-associated breast cancer even when diagnosed at an early stage, and that type of treatment does not influence prognosis.

Genetic variations in DNA repair genes, radiosensitivity to cancer and susceptibility to acute tissue reactions in radiotherapy-treated cancer patients

Ionizing radiation is a well established carcinogen for human cells. At low doses, radiation exposure mainly results in generation of double strand breaks (DSBs). Radiation-related DSBs could be directly linked to the formation of chromosomal rearrangements as has been proven for radiation-induced thyroid tumors. Repair of DSBs presumably involves two main pathways, non-homologous end joining (NHEJ) and homologous recombination (HR). A number of known inherited syndromes, such as ataxia telangiectasia, ataxia-telangiectasia like-disorder, radiosensitive severe combined immunodeficiency, Nijmegen breakage syndrome, and LIG4 deficiency are associated with increased radiosensitivity and/or cancer risk. Many of them are caused by mutations in DNA repair genes. Recent studies also suggest that variations in the DNA repair capacity in the general population may influence cancer susceptibility. In this paper, we summarize the current status of DNA repair proteins as potential targets for radiation-induced cancer risk. We will focus on genetic alterations in genes involved in HR- and NHEJ-mediated repair of DSBs, which could influence predisposition to radiation-related cancer and thereby explain interindividual differences in radiosensitivity or radioresistance in a general population.

Genetic markers for prediction of normal tissue toxicity after radiotherapy

During the last decade, a number of studies have supported the hypothesis that there is an important genetic component to the observed interpatient variability in normal tissue toxicity after radiotherapy. This review summarizes the candidate gene association studies published so far on the risk of radiation-induced morbidity and highlights some recent successful whole-genome association studies showing feasibility in other research areas. Future genetic association studies are discussed in relation to methodological problems such as the characterization of clinical and biological phenotypes, genetic haplotypes, and handling of confounding factors. Finally, candidate gene studies elucidating the genetic component of radiation-induced morbidity and the functional consequences of single nucleotide polymorphisms by studying intermediate phenotypes will be discussed.

Expression of estrogen receptor beta in the breast carcinoma of BRCA1 mutation carriers

BACKGROUND

Breast cancers (BC) in women carrying mutations in BRCA1 gene are more frequently estrogen receptor negative than the nonhereditary BC. Nevertheless, tamoxifen has been found to have a protective effect in preventing contralateral tumors in BRCA1 mutation carriers. The identification of the second human estrogen receptor, ERbeta, raised a question of its role in hereditary breast cancer. The aim of this study was to assess the frequency of ERalpha, ERbeta, PgR (progesterone receptor) and HER-2 expression in breast cancer patients with mutated BRCA1 gene and in the control group.

METHODS

The study group consisted of 48 women with BRCA1 gene mutations confirmed by multiplex PCR assay. The patients were tested for three most common mutations of BRCA1 affecting the Polish population (5382insC, C61G, 4153delA). Immunostaining for ERalpha, ERbeta and PgR (progesterone receptor) was performed using monoclonal antibodies against ERalpha, PgR (DakoCytomation), and polyclonal antibody against ERbeta (Chemicon). The EnVision detection system was applied. The study population comprised a control group of 120 BC operated successively during the years 1998-99.

RESULTS

The results of our investigation showed that BRCA1 mutation carriers were more likely to have ERalpha-negative breast cancer than those in the control group. Only 14.5% of BRCA1-related cancers were ERalpha-positive compared with 57.5% in the control group (P < 0.0001). On the contrary, the expression of ERbeta protein was observed in 42% of BRCA1-related tumors and in 55% of the control group. An interesting finding was that most hereditary cancers (75% of the whole group) were triple-negative: ERalpha(-)/PgR(-)/HER-2(-) but almost half of this group (44.4%) showed the expression of ERbeta.

CONCLUSION

In the case of BRCA1-associated tumors the expression of ERbeta was significantly higher than the expression of ERalpha. This may explain the effectiveness of tamoxifen in preventing contralateral breast cancer development in BRCA1 mutation carriers.

Late toxicity is not increased in BRCA1/BRCA2 mutation carriers undergoing breast radiotherapy in the United Kingdom

PURPOSE

To undertake the first substantial clinical study of breast radiotherapy toxicity in BRCA1 and BRCA2 mutation carriers in the United Kingdom.

EXPERIMENTAL DESIGN

Acute and late radiation effects were evaluated in a retrospective study of 55 BRCA1 and BRCA2 mutation carriers treated with radiotherapy for breast cancer at four centers between 1983 and 2002. Individual matching with controls who had sporadic breast cancer was undertaken for age at diagnosis, time since completion of radiation, and treatment variables. Detailed assessments were undertaken by one examiner. Median follow-up was 6.75 years for carriers and 7.75 years for controls. Rates of late events (rib fractures, lung fibrosis, necrosis of soft tissue/bone, and pericarditis) as well as LENT-SOMA scores and clinical photography scores of breast size, shape, and skin telangiectasia were the primary end points.

RESULTS

No increase in clinically significant late toxicity was seen in the mutation carriers.

CONCLUSIONS

These data add substantial weight to the evidence that the outcomes in the treated breast from radiotherapy in women with BRCA1 or BRCA2 mutations are comparable with those in women with sporadic breast cancer.

Treatment of hereditary breast cancer

Mutations in BRCA1 and BRCA2 are well-established causes of hereditary breast cancer. As genetic testing becomes more widespread, increasing numbers of women are known to have mutations at or shortly after their breast cancer diagnosis. Current evidence is insufficient to mandate different local or systemic treatment based upon the presence of a germline mutation. The well-documented increased risk of contralateral second primary breast cancer and possibly of late ipsilateral second primary breast cancers may influence patient decision-making with regard to breast-conserving treatment.

Practice Guideline for the Breast Conservation Therapy in the Management of Invasive Breast Carcinoma

This is the second of two articles reprinted with permission from: Practice guideline for breast conservation therapy in the management of invasive breast carcinoma. In: Practice Guidelines and Technical Standards. Reston, VA: American College of Radiology;2006:443-468. In this reprinting "G" in Section IV is available in the Online version only. For Section VI please refer to the first publication of ductal carcinoma in-situ (J Am Coll Surg 2007:205:145-161). Parts of this article have been shortened for brevity. The full article is available through the American College of Radiology. The American College of Radiology, with more than 30,000 members, is the principal organization of radiologists, radiation oncologists, and clinical medical physicists in the United States. The College is a nonprofit professional society whose primary purposes are to advance the science of radiology, improve radiologic services to the patient, study the socioeconomic aspects of the practice of radiology, and encourage continuing education for radiologists, radiation oncologists, medical physicists, and persons practicing in allied professional fields. The American College of Radiology will periodically define new practice guidelines and technical standards for radiologic practice to help advance the science of radiology and to improve the quality of service to patients throughout the United States. Existing practice guidelines and technical standards will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated. Each practice guideline and technical standard, representing a policy statement by the College, has undergone a thorough consensus process in which it has been subjected to extensive review, requiring the approval of the Commission on Quality and Safety as well as the ACR Board of Chancellors, the ACR Council Steering Committee, and the ACR Council. The practice guidelines and technical standards recognize that the safe and effective use of diagnostic and therapeutic radiology requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guideline and technical standard by those entities not providing these services is not authorized.

Prognostic value of BRCA1 mutations in familial breast cancer patients affected by a second primary cancer

The aim of this prospective study is to assess the prognostic value of BRCA1 mutations in familial breast cancer patients affected by a second primary cancer. The study group comprised 19 women having multiple primary breast cancers (breast-breast, breast-other primary) who were either BRCA1 mutation carriers, or not. Appearance of a second primary cancer was recognised as the event and survival and second primary free cancer survival was calculated from the date of diagnosis to the secondary primary cancer. The results of this study show that the event free survival of women with familial breast cancer affected by a second primary cancer, who are BRCA1 mutation carriers is better, compared with women from the general population with breast cancer selected for second primary cancer sites and all second primary sites -- P = 0.009 and P = 0.0078 respectively. In contrast, the event free survival of women with breast cancer affected by a second primary cancer, without a breast cancer family history, who are not BRCA1 mutation carriers is the same, as for women from the general population with breast cancer selected for second primary cancer sites and all second primary sites -- P = 0.6417 and P = 0.4859 respectively. The median time from diagnosis of the first to second primary cancer in the mutation carrying, and non-carrying, groups was 8,7 and 1,9 years respectively. In the study group, the highest event free survival rates had been observed among those carrying the said mutations -- 66.7% at 5 years, and 33.3% at 10 years -- in contrast with those not carrying the mutations, with rates of 30.8% and 15.4% respectively.

An overview of prognostic factors for long-term survivors of breast cancer

BACKGROUND

Numerous studies have examined prognostic factors for survival of breast cancer patients, but relatively few have dealt specifically with 10+-year survivors.

METHODS

A review of the PubMed database from 1995 to 2006 was undertaken with the following inclusion criteria: median/mean follow-up time at least 10 years; overall survival and/or disease-specific survival known; and relative risk and statistical probability values reported. In addition, we used data from the long-standing Eindhoven Cancer Registry to illustrate survival probability as indicated by various prognostic factors.

RESULTS

10-year breast cancer survivors showed 90% 5-year relative survival. Tumor size, nodal status and grade remained the most important prognostic factors for long-term survival, although their role decreased over time. Most studies agreed on the long-term prognostic values of MI (mitotic index), LVI (lymphovascular invasion), Her2-positivity, gene profiling and comorbidity for either all or a subgroup of breast cancer patients (node-positive or negative). The roles of age, socioeconomic status, histological type, BRCA and p53 mutation were mixed, often decreasing after correction for stronger prognosticators, thus limiting their clinical value. Local and regional recurrence, metastases and second cancer may substantially impair long-term survival. Healthy lifestyle was consistently related to lower overall mortality.

CONCLUSIONS

Effects of traditional prognostic factors persist in the long term and more recent factors need further follow-up. The prognosis for breast cancer patients who have survived at least 10 years is favourable and increases over time. Improved long-term survival can be achieved by earlier detection, more effective modern therapy and healthier lifestyle.

Multileaf field-in-field forward-planned intensity-modulated dose compensation for whole-breast irradiation is associated with reduced contralateral breast dose: a phantom model comparison

PURPOSE

Static multileaf collimated field-in-field forward-planned intensity-modulated radiation treatment (FiF-IMRT) has been shown to improve dose homogeneity compared to conventional wedged fields. However, a direct comparison of the scattered dose to the contralateral breast resulting from wedged and FiF-IMRT plans remains to be documented.

METHODS

The contralateral scattered breast dose was measured in a custom-designed anthropomorphic breast phantom in which 108 thermoluminescent dosimeters (TLDs) were volumetrically placed every 1-2cm. The target phantom breast was treated to a dose of 50Gy using three dose compensation techniques: No medial wedge and a 30-degree lateral wedge (M0-L30), 15-degree lateral and medial wedges (M15-L15), and FiF-IMRT. TLD measurements were compared using analysis of variance.

RESULTS

For FiF-IMRT, the mean doses to the medial and lateral quadrants of the contralateral breast were 112cGy (range 65-226cGy) and 40cGy (range 18-91 cGy), respectively. The contralateral breast doses with FiF-IMRT were on average 65% and 82% of the doses obtained with the M15-L15 and M0-L30 techniques, respectively (p<0.001). Compared to the M15-L15 technique, the maximum dose reduction obtained with FiF-IMRT was 115cGy (range 13-115cGy).

CONCLUSIONS

The dose to the contralateral breast is significantly reduced with FiF-IMRT compared to wedge-compensated techniques. Although long-term follow-up is needed to establish the clinical relevance of this finding, these results, along with the previously reported improvement in ipsilateral dose homogeneity, support the use of FiF-IMRT if resources permit.

Management of BRCA1/2 associated breast cancer: a systematic qualitative review of the state of knowledge in 2006

INTRODUCTION

The optimal clinical management of breast cancer (BC) arising in BRCA1/2 mutations carriers is a difficult issue complicated by the risk of subsequent malignancies and by the potential differences in response to local and systemic therapies.

AIM

Systematically review the difference in outcome after breast conservation therapy (BCT) and uni-or bilateral mastectomy in BRCA1/2 related BC.

MATERIAL AND METHODS

We selected 20 studies, for which we evaluated the methodology, the characteristics of the populations, biases, confounding risk factors and outcomes.

RESULTS

All studies are retrospective, entailed by numerous biases. They varied with respect to patients' number, selection, and confounding factors. Hereditary BC patients carried an increased risk of ipsilateral recurrence in 5/17 studies, a worse survival in 4/14, an increased risk of contralateral BC in 14/16.

CONCLUSION

Except for contralateral risk, the presence of a BRCA mutation does not seem to offer additional prognostic information. Large prospective trials, stratified for risk reduction strategies are warranted.

Prognosis of early-onset breast cancer based on BRCA1/2 mutation status in a French population-based cohort and review

PURPOSE

The debate concerning poorer survival for patients with breast cancer (BC) carrying a BRCA1 germline mutation is unresolved, and requires additional data from population-based studies.

PATIENTS AND METHODS

We followed 232 women with invasive BC under age 46, ascertained prospectively through a French population-based BC registry and tested for BRCA1/2 mutations (median follow-up: 82 months). We compared tumour characteristics and survival rates between 21 BRCA1/2 deleterious mutation carriers and 211 non-carriers.

RESULTS

As compared to sporadic tumours, BRCA1/2 tumours showed higher grade (P = 0.02), fewer ductal carcinoma in situ (P = 0.02), more frequent medullary histology (P = 0.02), more frequent negative oestrogen and progesterone receptors (P = 0.001 each). At 5 years, BC-specific survival, metastasis-free survival, ipsilateral recurrence-free survival and contralateral BC-free survival rates for BRCA1/2 mutation carriers were 95.0%, 94.7%, 100% and 90.0% respectively, compared with 89.6%, 78.2%, 88.8% and 94.4% respectively, for non-carriers (not significant). Rates for women carrying only a BRCA1 mutation were 93.3%, 93.3%, 100%, 86.7%, respectively. 76% of BRCA1/2 carriers received chemotherapy.

CONCLUSION

Despite unfavourable tumour features, we found no evidence for poorer short-term survival in BRCA1 mutation carriers compared to non-carriers in this prospective population-based cohort. The high rate of BRCA1 carriers who received chemotherapy for their BC should question the positive impact of this treatment, as suggested by preclinical studies showing increased chemosensitivity of BRCA1-associated tumours.