Breast cancer: In search of disorders in our genes
By: Diana Bello Aristizábal
October is Breast Cancer Awareness Month and another opportunity to reaffirm that prevention continues to be the best way to fight against this type of cancer, considered the most common one among women nationwide. But, when talking about prevention, one of the most important things to consider is personal and family medical history, which can help track genetic disorders that increase the risk of getting the disease.
“Around 15 percent of breast cancer cases are associated with a genetic predisposition. Knowing in advance whether or not we have disorders in our genes serves to make early detection and to reduce the risk of breast cancer,” Arelis Mártir-Negrón, M.D., FAMG, clinical geneticist with Baptist Health Miami Cancer Institute, explains.
An individual is considered to have a genetic disorder when tests show a change in a gene that is expected to cause issues. This is known as a mutation and although it doesn’t necessarily mean that the patient will develop cancer, it does increase the possibility.
“Everyone is at risk of developing breast cancer or any other type of cancer. However, a person with a genetic mutation has a higher risk compared to the general population,” Dr. Mártir-Negrón says.
Currently, 15 genes are known to be associated with breast cancer, of which 6 are of high risk, including BRCA1 and BRCA2. Showing mutations in these last two genes increases the chance of developing breast cancer by more than 60 percent. Other genetic disorders carry a risk of 20 percent or more depending on the case.
High-risk profile: Learning about the family history
The path to confirm if an individual has what is known as a genetic predisposition syndrome begins at home by talking to loved ones and asking questions to put together the family medical history.
Proceeding in this way is vital, because this approach helps gain information that can be shared in a pre-test appointment with a geneticist doctor, who will determine whether or not the patient meets the medical criteria to undergo genetic tests and will explain the legal protections against discrimination that apply in the event of a positive result.
The medical criteria are to have relatives in first-, second- or third-degree consanguinity who have suffered from breast cancer or associated cancers before the age of 50; multiple individuals on the maternal or paternal side with a history of breast cancer or associated cancers; breast cancer with ovarian or pancreatic cancer; or just breast or pancreatic cancer at any age.
In addition, is a valid criterion to be tested if there is a person in the family who has been diagnosed with several types of cancer, being of Ashkenazi Jewish descent or that a man in the family has had breast cancer. “Having three family members with breast cancer is already something suspicious,” the specialist warns.
On the other hand, having family members with a history of triple-negative cancer at any age is also a reason to run a genetic test. That is, if the receptor of the tumor found has been classified as such.
Once the doctor gives green light to a genetic test, they would discuss with the patient the size of the genetic predisposition panel to be performed, which means the number of genes to be analyzed as per the patient’s medical history and wishes. Tests can be collected by blood or saliva and results usually take 5 to 6 weeks to arrive.
And who should take the test? The patient who asks for the appointment or their relatives with a history of cancer? According to Dr. Mártir-Negrón, whenever possible the best alternative is for the affected family members to undergo the tests.
The reason behind this has to do with the fact that a negative result in the patient who requested the appointment doesn’t necessarily indicate the absence of a genetic disorder in the family. It may be present in the family but not inherited by the patient.
When the family member with a history of cancer is tested and the result comes back fine, is not necessary for the patient to take the genetic test so long as there is no history of cancer on both the maternal and paternal sides.
In this scenario, the risk of developing breast cancer would be calculated through statistical models and considering family history. It should be noted that even if no genetic disorder is found, the mere fact of having a family member with a history of breast cancer, especially if it is a close one, places the patient at a higher risk percentage than that of the general population. That risk increases by 50 percent if the test result is positive.
If the test comes back negative in the present time, there is no need to repeat it. However, if a patient was tested many years ago, it is advised to repeat the test, because in the past only BRCA1 and BRCA2 genes were often tested and not the other 13 genes. But even if the patient was tested for all the genes associated with breast cancer, a new test should be conducted due to the fact that 10 to 15 years ago the entire gene was not reviewed to see if it had missing or extra information, so an old test is considered incomplete.
A patient who currently has breast cancer may also undergo genetic testing. “It is valid to take the test, since it can help with surgical management and to know if there is a risk of developing other cancers or if the family is at risk,” the geneticist explains.
Recommendations after the test
Just as it is key to visit the doctor when there is suspicious of a genetic disorder, it is also key to follow specific recommendations after the test results are known. If a genetic mutation is confirmed in one of the 6 highest risk genes and there is no personal history of cancer, removing both breasts preventively may be an alternative.
In the case of a patient with a current diagnosis of breast cancer and an unfavorable result for any of the 6 high-risk genes, the treating doctor should recommend the best route to follow.
“Depending on the affected gene, the doctor will give specific recommendations. Therefore, it’s a good idea to make a post-test appointment to learn how to proceed further. In addition, the patient will receive a letter to share with the rest of the family members who would need to be tested.”
However, the overall recommendation for any type of genetic disorder is to run a mammography alternating with an MRI so that a diagnostic image is obtained every six months. “If something is growing, is best to detect it on time with the purpose of having a better prognosis,” the Dr. adds.
If the result is inconclusive, avoid jumping to the conclusion that something bad is happening unless it has been proven. In this situation, the way to proceed is to consult with a geneticist or genetic counselor who has the experience to explain the result and thus avoid a misdiagnosis.
In addition, we must not forget monthly self-examination, preventive mammography’s according to medical criteria, and to adopt a healthy lifestyle by limiting alcohol consumption, exercising, not smoking, and managing stress.