Breast cancer: pathogenesis and treatments

Breast cancer, characterized by unique epidemiological patterns and significant heterogeneity, remains one of the leading causes of malignancy-related deaths in women. The increasingly nuanced molecular subtypes of breast cancer have enhanced the comprehension and precision treatment of this disease. The mechanisms of tumorigenesis and progression of breast cancer have been central to scientific research, with investigations spanning various perspectives such as tumor stemness, intra-tumoral microbiota, and circadian rhythms. Technological advancements, particularly those integrated with artificial intelligence, have significantly improved the accuracy of breast cancer detection and diagnosis. The emergence of novel therapeutic concepts and drugs represents a paradigm shift towards personalized medicine. Evidence suggests that optimal diagnosis and treatment models tailored to individual patient risk and expected subtypes are crucial, supporting the era of precision oncology for breast cancer. Despite the rapid advancements in oncology and the increasing emphasis on the clinical precision treatment of breast cancer, a comprehensive update and summary of the panoramic knowledge related to this disease are needed. In this review, we provide a thorough overview of the global status of breast cancer, including its epidemiology, risk factors, pathophysiology, and molecular subtyping. Additionally, we elaborate on the latest research into mechanisms contributing to breast cancer progression, emerging treatment strategies, and long-term patient management. This review offers valuable insights into the latest advancements in Breast Cancer Research, thereby facilitating future progress in both basic research and clinical application.

Current overview and special considerations for second breast cancer in Hodgkin lymphoma survivors

Second breast cancer (SBC) is the most common solid cancer among Hodgkin Lymphoma (HL) female survivors. We reviewed the related modifying risk factors, radiation-induced carcinogenesis, tumors characteristics, management specificities, prevention and surveillance modalities based on current evidence. The risk of developing SBC may be influenced essentially by the age at HL treatment, follow-up latency, dose of irradiation received and the extent of irradiated field. SBCs generally develop at younger age, they are often bilateral, and exhibit more aggressive biological features and worse prognosis. No firm answer about the benefits of breast surveillance is provided by literature, but compelling evidence tends toward a clinical benefit in early detection. Increasing awareness among health providers' care and current survivors as well as the implementation of screening measures is crucial. Great efforts are ongoing in individualizing treatment strategies for future HL patients and response-adapted approaches are holding promise in prevention of these second malignancies.

Supplemental Screening for Patients at Intermediate and High Risk for Breast Cancer

The sensitivity of mammography is more limited in patients with dense breasts and some patients at higher risk for breast cancer. Patients with intermediate or high risk for breast cancer may begin screening earlier and benefit from supplemental screening techniques beyond standard 2-dimensional mammography. A patient's individual risk factors for developing breast cancer, their breast density, and the evidence supporting specific modalities for a given clinical scenario help to determine the need for supplemental screening and the modality chosen. Additional factors include the availability of supplemental screening techniques at an individual institution, cost, insurance coverage, and state-specific breast density legislation.

Nodes staging score to quantify lymph nodes for examination in gastric cancer

The lymph nodal invasion diagnosis is critical for therapeutic-decision and follows up in gastric cancer. However, the number of nodes to be examined for nodal invasion diagnosis is still under controversy, and the model for quantifying risk of missing positive node is currently not reported yet. We analyzed the nodal invasion status of 13,857 gastric cancer samples with records of primary tumor stage, the number of examined and positive lymph nodes in the surveillance, epidemiology, and end results (SEER) database, fitting a beta-binomial model. The nodes need to be examined with different primary tumor stage were determined based on the model. Overall, examining 11 lymph nodes reduces the probability of missing positive nodes to <10%, and the currently median nodes dissected is adequate (12 nodes). While the number of nodes demands to be dissected for T1, T2, T3, and T4 subgroups are 6, 19, 40, and 66, respectively. The currently implemented median value for these samples was 12, 12, 13, and 16, separately. It implies that the number of nodes to be examined is sufficient for early gastric cancer (T1), but it is inadequate for middle and advanced gastric cancer (T2-T3). The clinical significance of nodal staging score was validated with survival information. In summary, we first quantified the lymph nodes to be examined during surgery using a beta-binomial model, and validated with survival information.

Executive Summary of the Early-Onset Breast Cancer Evidence Review Conference

The Centers for Disease Control and Prevention launched the Bring Your Brave campaign to increase knowledge about early-onset breast cancer, defined as breast cancer in women aged 18-45 years. The American College of Obstetricians and Gynecologists convened a panel of experts in breast disease from the Society for Academic Specialists in General Obstetrics and Gynecology to review relevant literature, validated tools, best practices, and practice guidelines as a first step toward developing educational materials for women's health care providers about early-onset breast cancer. Panel members conducted structured literature reviews, which were then reviewed by other panel members and discussed at an in-person meeting of stakeholder professional and patient advocacy organizations in April 2019. This article summarizes the relevant literature, existing guidance, and validated tools to guide health care providers in the prevention, early detection, and special considerations of early-onset breast cancer. Substantive knowledge gaps were noted and summarized to provide guidance for future research.

Quantifying the number of lymph nodes for examination in breast cancer

OBJECTIVE

Examining the correct number of lymph nodes when diagnosing breast cancer invasion is still a problem. This work aimed to develop a qualification model that estimates the possibility of missing nodes and the number of lymph nodes that need to be examined.

METHODS

By analyzing lymph node invasion of 303,760 breast cancer samples with primary tumor stage and the number of examined and positive lymph nodes from the Surveillance, Epidemiology and End Results database using a beta-binomial model, the number of nodes that should be examined was quantified in different stages.

RESULTS

In general, to reduce the possibility of missing positive nodes to less than 10%, 21 lymph nodes should be examined; thus, the current median of dissected nodes (12) is not adequate. The number of nodes needed to be dissected for stages T1, T2, and T3 are 8, 37, and 87, respectively. Currently, the median number of node dissections for these stages were 12, 13, and 14, respectively. The clinical significance of the nodal staging score was validated with survival information.

CONCLUSION

Currently, the number of lymph nodes dissected in breast cancer are excessive for T1 but insufficient for T2 and T3.

Contraception in cancer survivors - an expert review Part I. Breast and gynaecological cancers

Objective: The efficacy of treatment for many cancers has increased dramatically in recent decades and there are a growing number of cancer survivors who need effective contraception. In this paper, a group of experts from the European Society of Contraception set out to define the most frequent cancers in women and summarise the guidelines, reviews and studies that provide information and guidance on contraception for each cancer. Methods: Epidemiological studies were analysed to determine the frequency of cancers in women of reproductive age. A narrative review was performed for each cancer, collecting data about the treatment of the disease, its impact on fertility, and the efficacy, health risks, possible benefits and contraindications of the contraceptive methods available. The recommendations were then summarised. Results: Owing to a large amount of information, the results are presented in two parts. Part 1 includes contraception after breast and gynaecological cancers. Part 2 summarises the findings and recommendations regarding contraception in women with skin, gastrointestinal, haematological and endocrine cancers.

STARD: How many lymph nodals needed to be dissected in corpus carcinoma?

During corpus carcinoma surgery, there is uncertainty as to how many lymph nodes should be dissected and examined to determine lymph invasion.In this study, we evaluated a beta-binominal model in data extracted from the Surveillance, Epidemiology, and End Results (SEER) database, which contains 22,372 complete records. We quantified the relationship between examined node number and the probability of missing invaded nodes. Survival curves were used for further validation.We found that for stage T1-T4, 1, 10, 23, and 37 lymph nodes, respectively, needed to be examined to minimize the missing positive nodal probability (1-nodal staging score, NSS) to less than 5%. A hypothetical lymph node examination rate was calculated. Survival rate of T2 and T3 stage samples was significantly associated with NSS, but T1 and T4 sample survival rate was not.The currently dissected nodal should be reduced to 1 to 2 for T1, remains to 10 for T2, and increases to 23 for T3.

Clinical and histological features of second breast cancers following radiotherapy for childhood and young adult malignancy

OBJECTIVE

The purpose of this study was to determine the characteristics of early second breast cancer (SBC) among survivors of childhood and young adult malignancy treated with irradiation.

METHODS

We conducted a multicenter retrospective study of women who presented with breast cancer aged 50 years or younger in nine French centers.

RESULTS

121 patients and 141 SBC were analyzed (invasive = 130; non-invasive = 11). The mean age at first cancer diagnosis was 15 years and at initial SBC diagnosis was 38 years. Bilateral disease before the age of 51 years was diagnosed in 16% of the females. The majority of SBC were invasive carcinomas (92%). Among the invasive carcinomas, 39% had a histoprognostic score of III, 3.1% overexpressed HER2 and 29% were triple negative. The proportion of triple negative phenotype SBC was higher in patients older at first cancer diagnosis [RR = 1.2, 95% CI (1.1-1.3)]. 94% of triple negative SBCs developed in breast tissue which had received >20 Gy.

CONCLUSION

We found a high proportion of aggressive SBC following thoracic radiotherapy in childhood or early adulthood. Advances in knowledge: SBC screening is recommended by scientific societies for these child/young-adulthood cancer survivors in the same way as the one for high risk women because of constitutional mutations. Our results support these recommendations, not only because of a similar cumulative risk, but also because of the aggressive histological characteristics.

Targeting TGF-β Signaling for Therapeutic Gain

Transforming growth factor βs (TGF-βs) are closely related ligands that have pleiotropic activity on most cell types of the body. They act through common heterotetrameric TGF-β type II and type I transmembrane dual specificity kinase receptor complexes, and the outcome of signaling is context-dependent. In normal tissue, they serve a role in maintaining homeostasis. In many diseased states, particularly fibrosis and cancer, TGF-β ligands are overexpressed and the outcome of signaling is diverted toward disease progression. There has therefore been a concerted effort to develop drugs that block TGF-β signaling for therapeutic benefit. This review will cover the basics of TGF-β signaling and its biological activities relevant to oncology, present a summary of pharmacological TGF-β blockade strategies, and give an update on preclinical and clinical trials for TGF-β blockade in a variety of solid tumor types.

Comparative study of the effects of different radiation qualities on normal human breast cells

BACKGROUND

As there is a growing number of long-term cancer survivors, the incidence of carcinogenesis as a late effect of radiotherapy is getting more and more into the focus. The risk for the development of secondary malignant neoplasms might be significantly increased due to exposure of healthy tissue outside of the target field to secondary neutrons, in particular in proton therapy. Thus far, the radiobiological effects of these neutrons and a comparison with photons on normal breast cells have not been sufficiently characterised.

METHODS

MCF10A cells were irradiated with doses of up to 2 Gy with neutrons of different energy spectra and X-rays for comparison. The biological effects of neutrons with a broad energy distribution ( = 5.8 MeV), monoenergetic neutrons (1.2 MeV, 0.56 MeV) and of the mixed field of gamma's and secondary neutrons ( = 70.5 MeV) produced by 190 MeV protons impinging on a water phantom, were analysed. The clonogenic survival and the DNA repair capacity were determined and values of relative biological effectiveness were compared. Furthermore, the influence of radiation on the sphere formation was observed to examine the radiation response of the potential fraction of stem like cells within the MCF10A cell population.

RESULTS

X-rays and neutrons caused dose-dependent decreases of survival fractions after irradiations with up to 2 Gy. Monoenergetic neutrons with an energy of 0.56 MeV had a higher effectiveness on the survival fraction with respect to neutrons with higher energies and to the mixed gamma - secondary neutron field induced by proton interactions in water. Similar effects were observed for the DNA repair capacity after exposure to ionising radiation (IR). Both experimental endpoints provided comparable values of the relative biological effectiveness. Significant changes in the sphere formation were notable following the various radiation qualities.

CONCLUSION

The present study compared the radiation response of MCF10A cells after IR with neutrons and photons. For the first time it was shown that monoenergetic neutrons with energies around 1 MeV have stronger radiobiological effects on normal human breast cells with respect to X rays, to neutrons with a broad energy distribution ( = 5.8 MeV), and to the mixed gamma - secondary neutron field given by interactions of 190 MeV protons in water. The results of the present study are highly relevant for further investigations of radiation-induced carcinogenesis and are very important in perspective for a better risk assessment after secondary neutron exposure in the field of conventional and proton radiotherapy.

Pregnancy and Breast Cancer

Breast cancer is the most commonly diagnosed type of cancer among women worldwide. The majority of breast cancers are sporadic and the etiology is not well understood. Several factors have been attributed to altering the risk of breast cancer. A full-term pregnancy is a crucial factor in altering the risk. Early full-term pregnancy has been shown to reduce the lifetime risk of breast cancer, while a later first full-term pregnancy increases breast cancer risk. Epidemiological and experimental data demonstrate that spontaneous or induced abortions do not significantly alter the risk of breast cancer. In this study, we briefly discuss the different types and stages of breast cancer, various risk factors, and potential mechanisms involved in early full-term pregnancy-induced protection against breast cancer. Understanding how early full-term pregnancy induces protection against breast cancer will help design innovative preventive and therapeutic strategies. This understanding can also help in the development of molecular biomarkers that can be of tremendous help in predicting the risk of breast cancer in the general population.

State of the evidence 2017: an update on the connection between breast cancer and the environment

BACKGROUND

In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available.

CONCLUSION

Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.

A French national breast and thyroid cancer screening programme for survivors of childhood, adolescent and young adult (CAYA) cancers - DeNaCaPST programme

Background

Survival of childhood, adolescent and young adult (CAYA) cancers has increased with progress in the management of the treatments and has reached more than 80% at 5 years. Nevertheless, these survivors are at great risk of second cancers and non-malignant co-morbidities in later life. DeNaCaPST is a non-interventional study whose aim is to organize a national screening for thyroid cancer and breast cancer in survivors of CAYA cancers. It will study the compliance with international recommendations, with the aim, regarding a breast screening programme, of offering for every woman living in France, at equal risk, an equal screening.

Method

DeNaCaPST trial is coordinated by the INSERM 1018 unit in cooperation with the LEA (French Childhood Cancer Survivor Study for Leukaemia) study’s coordinators, the long term follow up committee and the paediatric radiation committee of the SFCE (French Society of Childhood Cancers).

A total of 35 centres spread across metropolitan France and la Reunion will participate. FCCSS (French Childhood Cancer Survivor Study), LEA and central registry will be interrogated to identify eligible patients. To participate, centers agreed to perform a complete “long-term follow-up consultations” according to good clinical practice and the guidelines of the SFCE (French Society of Children Cancers).

Discussion

As survival has greatly improved in childhood cancers, detection of therapy-related malignancies has become a priority even if new radiation techniques will lead to better protection for organs at risk. International guidelines have been put in place because of the evidence for increased lifetime risk of breast and thyroid cancer. DeNaCaPST is based on these international recommendations but it is important to recognize that they are based on expert consensus opinion and are supported by neither nonrandomized observational studies nor prospective randomized trials in this specific population. Over-diagnosis is a phenomenon inherent in any screening program and therefore such programs must be evaluated.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3318-1) contains supplementary material, which is available to authorized users.