Millions survive breast cancer, but the disease needs vigilance

 

It’s estimated that about 7% of all breast cancer cases diagnosed occur in women under the age of 40. According to the American Cancer Society, about one in eight invasive breast cancers develop in women younger than 45, whereas two in three invasive breast cancers occur in women aged 55 or older. Breast cancer occurrence also differs between patients diagnosed before and after menopause.

Although breast cancer may occur in men, its occurrence is rare, and one in a thousand men may be diagnosed with breast cancer in their lifetime.

Breast cancer is regarded as a heterogeneous disease — the way it develops and affects individual patients varies greatly. Some breast cancer subtypes are hormone-dependent. Breast cancer cells that possess oestrogen receptors are defined as oestrogen-positive (ER+). Breast cancer cells containing progesterone receptors are called progesterone-positive (PR+) cancers. Hormone receptor-positive cancers occur more frequently. Hormone receptor-positive cancers also have improved prognosis. Hormone receptor-negative cancers may be more difficult to treat, and have the likelihood of a higher pathological grade.

Survival rates for breast cancer differ worldwide. The five-year survival rate for women diagnosed with stage I/II breast cancer (defined as small tumours and local metastasis to nodes under the arm) is 80% to 90%. With regard to breast cancer stages III/IV, where there are larger tumours present or metastasis has occurred beyond the breast and to distant organs, a 24% survival rate has been reported. But, according to the World Health Organisation, 30% to 50% of all cancer cases are preventable, and survival rates are improving. Improvement in survival rates can be attributed to factors including advances in access to medical care, early detection and diagnosis at a localised stage, improved surgical procedures, personalised adjuvant treatment regimens and precision medicine.

Only a fraction of cancers is attributed to an inherited condition. If cancer is common in a family, the possibility exists that mutations are being passed from one generation to the next. Genetic predisposition to cancer doesn’t necessarily indicate that a person with such a mutation will be diagnosed with cancer; only 5% to 10% of all cancers can be attributed to genetic inheritance. Gene mutations may occur for several other reasons, namely gene mutations inherited from parents or gene mutations that occur after birth.

Remarkably, mutations in the tumour suppressor genes — breast cancer type 1 susceptibility protein (BRCA1) and breast cancer type 2 susceptibility protein 2 (BRCA2) — may increase a person’s susceptibility to develop breast cancer, and also at a younger age. There are high penetrance mutations in these genes associated with breast cancer. In addition, these mutations increase the risk of other cancer types. A dangerous BRCA1 or BRCA2 mutation can be inherited from a child’s mother or father. Every child of a parent who has a mutation in one of the BRCA1 and BRCA2 genes has a 50% chance of inheriting the harmful mutation.

Genetic tests (for example next-generation sequencing) are available to assess for these harmful cancer markers. Deoxyribonucleic acid (DNA), usually from blood, is used to conduct these assays. About 55% to 65% of women with certain BRCA1 mutations and 45% of women with BRCA2 mutations may develop breast cancer before the age of 70. In addition, research has shown that women with a BRCA1 or BRCA2 mutation may experience recurrence of cancer after treatment. BRCA1 mutations usually lead to aggressive triple-negative breast cancer that is difficult to treat.

With early detection, a huge number of breast cancer cases can be treated, including patients with a BRCA1 or BRCA2 mutation. Doctors can assist in recommending gene assessments for harmful gene mutations, keeping in mind a family’s cancer history.

Subsequent to her mother’s breast cancer illness and death of ovarian cancer at 56, actor Angelina Jolie announced in 2013 that she had undergone a double mastectomy. Jolie, who was then 37 years old, reported that she has a genetic mutation of BRCA1, which prompted her decision. She stated after her surgery: “My chances of developing breast cancer have dropped from 87% to less than 5% [after my double mastectomy].”

It is important to keep in mind that researchers have identified mutations in multiple genes (other than the BRCA1 and BRCA2) that also contribute to the risk of breast cancer (less than 10% of women who have been diagnosed with breast cancer have the BRCA mutation). Another example is partner and localiser of BRCA2 (PALB2), where moderate penetrance mutations have been associated with breast cancer.

Preventative surgery may decrease the risk of breast cancer, but does not provide a 100% certainty that the person will not develop cancer. Frequent surveillance and screenings should be considered. Medication as preventative therapy may also be considered to assist high-risk women to decrease their risk of being diagnosed with cancer.

Many gene mutations may occur during a person’s life and are therefore not inherited. The latter may be triggered by fundamental risk factors including acute or chronic stress, alcohol consumption, tobacco products, diet, lack of physical activity, pollutants, ultraviolet radiation, reproductive and hormonal factors, occupational exposures and infection-attributable cancers.

Precision or personalised medicine aims to deliver precise treatment to patients based on mutations present in their tumours. Precision medicine contributes to the development of therapies that will target the cancer cells or cellular pathways affected with minimal trauma and side effects, thereby influencing the treatment selected by physicians to improve quality of life.

The elimination of cancer requires a combination of cancer awareness to address the burden of this disease — prevention strategies, contributing to early detection and promoting health and well-being education and the acceleration of science and discovery and progress in technology.

October is Breast Cancer Awareness Month in South Africa, which highlights an important drive by private and public healthcare organisations to increase breast cancer awareness nationally. Although there is no one-size-fits-all treatment for cancer patients, there are millions of cancer survivors worldwide, emphasising that there is hope, and that what will happen next might just change the world.

Professor Annie Joubert is Head of the University of Pretoria’s Department of Physiology in the Faculty of Health Sciences.

This article first appeared in the Mail & Guardian on 30 October 2019.

Professor Annie Joubert

October 30, 2019

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Researchers
  • Professor Annie Joubert
    Professor Joubert commenced research in molecular and cellular cancer physiology at the University of Pretoria (UP) in 1998 when she was appointed as a senior technical assistant in the Department of Physiology after obtaining a PhD in Biochemistry (UP).

    Through her work, she hopes to strengthen collaborations with industry, and national and international research collaborations with the University of Oxford (UK), University of Bath (UK), University of Florida (USA), Baylor College of Medicine (USA), CRI INSERM (France), Joseph Fourier University (France) and Sabanci University (Turkey).

    The focus of Prof Joubert’s research is mainly breast cancer, which is one of the most common forms of the disease in women – the lifetime risk of South African women getting breast cancer is one in 27. Her research focuses specifically on:
    a) the in silico design performed by computer simulation of potential anti-cancer agents;
    b) the chemical synthesis thereof in liaison with a pharmaceutical company; and
    c) the evaluation of these agents for improved anti-cancer treatment.

    The prevalence of cancer is increasing worldwide. Globally, 14 million people are diagnosed with the disease each year, and about nine million lose their lives to it annually. According to the Cancer Association of South Africa, breast cancer in women and prostate cancer in men are among the top five cancers prevalent in the country. However, according to the World Health Organisation, between 30 and 50% of all cancer cases are preventable.

    The research findings of Prof Joubert’s group contribute to the use of in silico virtual screening (VS) methods to identify lead compounds that are likely to succeed in further downstream assays and screens, including whole genome microarrays as well as protein arrays, in the search for potential anti-cancer agents. Making use of in silico VS methods helps scientists to identify novel compounds that significantly lower the cost of drug development by negating the need to synthesise unnecessary compounds that could not be removed prior to screening.

    Prof Joubert is also contributing to translational research that entails scientific discoveries that can be applied to improve health outcomes and health care in the Faculty of Health Sciences and the Faculty of Natural and Agricultural Sciences at UP, thus addressing the United Nations’ Sustainable Development Goal 3 (Good Health and Well-being).

    She recently commenced with a leukaemia research project that looks at the role of platelets in the progression of chronic myeloid leukaemia, a condition that affects mostly older adults and is a type of leukaemia of the haematopoietic stem cells. Her fundamental cancer research links with clinical research, further contributing to translational research with a specific benefit for South African and African populations with unique genotypic and phenotypic characteristics.

    Prof Joubert’s research efforts were prompted by the passing of her father, after he was diagnosed with chronic myeloid leukaemia in September 2020 and COVID-19. She says that he taught her to believe in herself and to do her part to improve the quality of life of the people that she interacts with every day. Her other role models are Prof Albert Neitz, who supervised her PhD degree, and Prof Dirk van Papendorp, Head of the Department of Physiology. Both academics inspired her and motivated her to go the extra mile in her career, Prof Joubert says.

    Keeping in mind the life skills her father taught her, Prof Joubert dreams of touching lives and hopes to be regarded as a good mentor to students and colleagues. “I would like to be remembered for having contributed to someone’s life in a positive way, whether it is teaching undergraduates and postgraduates, or contributing to the good health and well-being of all people.”

    For relaxation, she enjoys pilates and gardening.
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