Worried About Breast, Ovarian Cancer? Genetic Testing Could Help
India
accounts for the third highest number of breast cancer and second
highest number of ovarian cancer cases among women, globally. Also,
three times more cases of familial breast and ovarian cancers are
recorded in India, as compared to western countries. It is projected
that cancer incidence in Indian women will increase to 190-200 cases per
lakh by 2025. Mortality to incidence ratio
is worst in India for breast and ovarian cancers with one in every 28
women likely to develop it during her lifetime and one in every two
women diagnosed with it, succumbing to it.
Harmful mutations (multiple changes in DNA sequence) in BRCA1 and BRCA2 genes are known to be associated with high risk of developing hereditary breast and ovarian cancer (HBOC) syndrome (Table 1).
About 20-25 percent of breast cancer cases are attributed to mutations in BRCA1 and BRCA2 genes. There is also an increased risk of developing cancer in other breast and/or ovarian cancer, after the first onset of breast cancer, in women who carry mutated BRCA1 or BRCA2 genes.
Harmful mutations (multiple changes in DNA sequence) in BRCA1 and BRCA2 genes are known to be associated with high risk of developing hereditary breast and ovarian cancer (HBOC) syndrome (Table 1).
About 20-25 percent of breast cancer cases are attributed to mutations in BRCA1 and BRCA2 genes. There is also an increased risk of developing cancer in other breast and/or ovarian cancer, after the first onset of breast cancer, in women who carry mutated BRCA1 or BRCA2 genes.
The harmful germline mutations in other genes such as TP53, CHEK2, STK11, BARD1, ATM, BRIP1, CDH1, PALB2, RAD51C, RAD51D, RAD50, NBS1, PTEN accounts for about 10 percent of familial breast and ovarian cancer cases.
Next Generation Sequencing based genetic test is a blood test that uses technique to analyse genomic DNA for detecting mutations in the multiple genes in a single assay. This is a highly sensitive and robust sequencing method that generates more reliable results. It is a comprehensive assay covering single nucleotide variations (SNVs) and short insertions and deletions (InDels) and a cost-effective alternative to other available techniques with a shorter turnaround time.
BRCA1 and BRCA2 genetic test helps to identify the hereditary risk (presence of personal or family history) accurately and also helps to recognise the disease prognostication (impact on overall survival rate of breast cancer patients) and adds theragnostic value (deciding the best drug treatment). One of the most important utilities of the test is to improve early detection by 1.5 to 2.5 times and, therefore, increase the overall survival and reduce the cost of treatment.
Next Generation Sequencing based genetic test is a blood test that uses technique to analyse genomic DNA for detecting mutations in the multiple genes in a single assay. This is a highly sensitive and robust sequencing method that generates more reliable results. It is a comprehensive assay covering single nucleotide variations (SNVs) and short insertions and deletions (InDels) and a cost-effective alternative to other available techniques with a shorter turnaround time.
BRCA1 and BRCA2 genetic test helps to identify the hereditary risk (presence of personal or family history) accurately and also helps to recognise the disease prognostication (impact on overall survival rate of breast cancer patients) and adds theragnostic value (deciding the best drug treatment). One of the most important utilities of the test is to improve early detection by 1.5 to 2.5 times and, therefore, increase the overall survival and reduce the cost of treatment.
Who Should Get Tested?
Genes
are inherited, therefore, knowing your family history is significant
when determining breast cancer risks. If either of your parents has a BRCA1 or BRCA2
mutation, you have a 50 percent chance of inheriting the mutated gene.
One should consider gene testing if any one of the following conditions
are predominant:
- A personal history of breast or ovarian cancer diagnosed at young age (pre-menopausal), bilateral breast cancer (affecting both breasts) or presence of both ovarian and breast cancer
- A family history of breast, ovarian, fallopian tube, peritoneal, prostate, or pancreatic cancer
- A male family member having breast cancer
- A relative with a known deleterious mutation in BRCA1 or BRCA2 genes
- A history of breast cancer diagnosed below the age of 45 years
- A family member with bilateral breast cancer below the age of 50
- An individual with triple negative breast cancer below the age of 60 years with or without family history
- Two or more relatives with ovarian cancer
- Both breast and ovarian cancers in either the same woman or the same family
- Ashkenazi Jewish ethnicity
i) A positive test result
in an asymptomatic individual would help in disease prevention, early
detection and better management of the disease by increased
surveillance, using risk reducing chemoprevention and/or surgical
interventions. Bilateral total mastectomy and oophorectomy may also
reduce the risk of breast cancer and ovarian cancer in mutation
carriers.
ii) A negative test result means there is no mutation in BRCA1 and BRCA2 genes. A person with negative test result holds same risk of developing breast cancer as someone in the general population.
iii) An ambiguous result occurs when a genetic test finds a change in BRCA1 or BRCA2 that has not been reported to be directly associated with breast cancer till date. This type of test result may be described as “a genetic variant of uncertain significance” because it is not known whether this specific genetic change is harmful. A study in Asian women found that 7.8 percent of women who underwent BRCA1 and BRCA2 mutation testing had this type of ambiguous result.
ii) A negative test result means there is no mutation in BRCA1 and BRCA2 genes. A person with negative test result holds same risk of developing breast cancer as someone in the general population.
iii) An ambiguous result occurs when a genetic test finds a change in BRCA1 or BRCA2 that has not been reported to be directly associated with breast cancer till date. This type of test result may be described as “a genetic variant of uncertain significance” because it is not known whether this specific genetic change is harmful. A study in Asian women found that 7.8 percent of women who underwent BRCA1 and BRCA2 mutation testing had this type of ambiguous result.
In
newly diagnosed patients with breast or ovarian cancer, gene test
results help to guide disease management and drug treatment decisions.
Genetic counseling is highly recommended before undergoing genetic test (pre-test counseling) and after the results are disclosed (post-test counseling). Genetic counselor can help decide whether genetic testing is needed based on the personal and family history and various other risk factors. If genetic testing is indicated, it should occur early in the cancer trajectory as patients who carry a mutation may receive more aggressive treatment.
Genetic counseling is highly recommended before undergoing genetic test (pre-test counseling) and after the results are disclosed (post-test counseling). Genetic counselor can help decide whether genetic testing is needed based on the personal and family history and various other risk factors. If genetic testing is indicated, it should occur early in the cancer trajectory as patients who carry a mutation may receive more aggressive treatment.
this is only for your
information, kindly take the advice of your doctor for medicines,
exercises and so on.
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Labels: blood tests, BRCA1 & 2, breast and ovarian cancers, Fallopian tubes, family history, genetic tests, mastectomy, mutations, oophorectomy, prostate or pancreatic cancers, triple negative breast cancer
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