Is breast cancer hereditary in men, women? Are your children, siblings at risk?
Breast Cancer Awareness Month 2022: If you have breast cancer, will your children also have it? What is the risk for family members? What is genetic testing? How will it help? Here's all you need to know
One of the most common fears that an individual has during and after battling any cancer is whether their children or siblings are also at risk for cancer. The common notion around cancer, especially breast cancer, is that if the mother has breast cancer then her children will also have it.
In reality, only 5-10% of all cancers are hereditary (which can pass on to the next generation) and are caused due to changes in our genes (variants) present from birth. Some tests can detect such hereditary cases and thus give us time to act on them before developing symptoms.
In an interview with HT Lifestyle, Dr Kanury VS Rao, Co-Founder and Chief Scientific Officer (CSO) at PredOmix, shared, "While family history is an important risk factor, this does not mean that every woman with a family history of breast cancer will necessarily get the disease. Instead, what this implies is that women who have close blood relatives (mother, sister, or daughter) with breast cancer have a higher risk for this disease relative to the general population. Having one blood relative with breast cancer doubles the risk, whereas the risk is increased to about 3-fold for women who have two blood relatives with the disease. It is important to note, though, that only between 15% to 20% of breast cancer cases are those in women with a family history of cancer. The remaining 80% to 85% of breast cancers occur in women with no family history of the disease. Environmental and lifestyle factors, including diet, have now been recognized to also constitute significant risk factors for breast cancer."
According to Dr Saima Naz Khan Senior, Manager- Scientific Affairs at Genes2Me, breast cancer does run in genes however the possibility of breast cancer depends on person to person in a family, for example if the mother has breast cancer it is not a surety that the cancer will be diagnosed in the child since the possibility of genes mutating exists. She said, “Apart from breast Cancer a lot of reproductive cancers are multigenic in nature for example BRCA1 or BRCA2 are major genes responsible for breast cancer however there are more genes which are now coming up that are contributory towards breast cancer. Some other genes play additional roles in modifying the metabolic pathways and one individual can become susceptible to cancer. It could be any type of cancer variety or reproductive. Mode of inheritance also plays a vital role in defining the existence of cancer and the susceptibility of cancer depending on the number of generations in which the cancer has lived in the family.”
This Breast Cancer Awareness Month, Dr Kunjal Patel, Molecular Oncopathologist and Sushma Patil, Lead Genetic Counselor at Neuberg Centre for Genomic Centre, answered a few queries related to breast cancer:
Q: If I have breast cancer, will my children also have breast cancer?
A: No. The risk of developing breast cancer is not 100%. Only 5-10% of cases of cancers are hereditary. The risk of developing breast cancer in your children depends on the type of cancer, age of diagnosis, and family history of other types of cancers. The exact risk can be ascertained by certain risk scores which can help in early detection and treatment. Genetic counselors can help assess your risk for hereditary cancers.
Q: What is the risk for my family members?
A: Once a family-specific variant is identified by genetic testing, screening for that variant can be offered to first-degree relatives. There is a 50% chance that they might inherit the same variant. Having the variant increases a person’s risk for cancer, but it does not mean that she/he will get cancer in the future.
Q: What is genetic testing? How will it help?
A: A genetic test can help to identify the genetic change/ variant which is causing cancer in the family. It has to be first offered to the affected individual. If the test is positive, the diagnosis is confirmed in the affected individual. For the asymptomatic siblings/ children, if it is positive, there are potential benefits such as targeted surveillance, early disease detection, undergoing risk-reducing surgeries, and can help a person make lifestyle changes, lowering their risk for the disease.
Eg: A mutation in the BRCA gene increases the risk of an individual for breast and ovarian cancer. In such cases, regular follow-ups with mammography/ MRI of the breast help in the early detection of cancer, which can lead to better treatment outcomes. Options like prophylactic risk-reducing surgeries could be discussed with the referring oncologist.
If the test is negative, it can provide a sense of relief and reduce the anxiety of the individual or family members. But it does not truly negate the possibility of having cancer, as a background risk persists. Though it can help in deciding further, the need and interval of screening required for cancer in that individual.
Q: When should I discuss the hereditary aspect of my cancer with a doctor/genetic counselor?
A: A doctor/ genetic counselor should be consulted in the following cases:
· Diagnosed with Breast Cancer at < 50 yrs of age
· Diagnosed with triple-negative breast cancer < 60yrs
· Ovarian /Pancreatic/Prostate/ male breast cancer at any age
· Anxious about daughters'/ extended family members' risk for cancer
· Have a family history of cancers
· Would like to discuss a hereditary aspect of cancer
Q: Who are Genetic Counsellors? What happens at a genetic counseling session?
A: A Genetic Counsellor, is a health care professional who is trained in medical genetics and counseling. The counselling sessions typically start with the counselor taking a detailed medical and family history. This is followed by risk assessment based on National Comprehensive Cancer Network (NCCN) guidelines, which is an alliance of 32 leading cancer centers devoted to patient care, research, and education. In case one is at risk for hereditary cancers based on these criteria, genetic testing is offered.
To summarize, not all cancers (including breast cancers) are hereditary. You should approach your doctor/genetic counselor, in case a cancer is running in your family or you are worried about your child/sibling inheriting the cancer risk.