BRCA mutations significantly increase the risk of ovarian cancer. These mutations impair the ability to repair damaged DNA, allowing cancer to develop. For patients diagnosed with ovarian cancer, BRCA testing helps identify high-risk family members and allows for preventative measures. Prophylactic surgery can reduce ovarian cancer risk by 35-50% in BRCA mutation carriers. PARP inhibitors have also shown promise in treating ovarian cancers associated with BRCA mutations.
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BRCA Mutation Role in Ovarian Cancer Risk and Treatment
1. BRCA mutation in
ovarian cancer
Prepared by: Zul Azmi Sutaji
Supervisor: AP Dr Mohamad Nasir Shafiee
2. Outlines
Introduction
Role of BRCA in ovarian cancer development
Implication of BRCA testing in ovarian cancer
Role of prophylactic surgery in BRCA mutation patients
Oral contraceptives and BRCA mutation carriers
Treatment consideration in germline BRCA mutation
carriers
PARP inhibitors
Conclusion
3. Introduction
Ovarian cancer: 4th common women cancer, approximately 700 new cases per
year in Malaysia
Incidence peak: 45 -70 years old
56% presented at late stage (Stage 3, 4)
90% is epithelial type, which accounts ~70% is in high-grade serous carcinoma
(HGSC) form
One of the most significant risk factor: genetic mutation of BRCA1/2 gene
HGSC highly mutated cancer, 96% most notably had mutation at p53 and
BRCA1/2 gene
Among women with BRCA1/2 mutation, risk developing ovarian cancer is 44%
and 17% respectively
1. Malaysian National Cancer Registry Report 2007-2011
2. Hasmad et al., (2016)
4. BRCA gene is a tumour suppressor gene, 2 types been identified
BRCA1 has the cytogenetic location 17q21, while BRCA2 is 13q12
Both genes produce proteins that important in helping repair damaged DNA
due to double-strand break (DSB) by keeping genetic material stable and
functional
Majority BRCA1/2 mutation leads preferentially to cancer of breast and ovary
Women with mutation in BRCA1 or BRCA2 gene have a risk of breast cancer
about 5 times, and risk of ovarian cancer about 10-30 times than normal
population
1. Kuchenbaecker et al., (2017)
5. Role of BRCA in ovarian cancer development
Two mechanisms of BRCA gene action in repair a double-strand break:
Non-homologous end joining: Causes open ends of the DNA to attach binding protein
and ultimately reconnect the sides of the DNA
Homologous recombination: Repairing unaltered reading frame. From the open ends, a
single strand 3’ opening is formed
BRCA1is a part of a larger complex molecule that helps to survey the DNA for DSB
damage
Role of BRCA2 is less clear, but it likely has direct role in repair by assisting the
RAD51 complex in attaching to repair site
Mutation in BRCA gene mean that the protein that repairs DNA damage changes
shape and is non-functional. This can increase the chances of cancer developing
1. Gudmundsdottir et al., (2006)
2. Yang et at., (2002)
3. O’Connor et al., (2015)
6. Of all patients who are
diagnosed with serous ovarian
carcinoma, over 15% will have a
germline BRCA mutation
(gBRCAmut) present
The average cumulative risk of
developing ovarian cancer with a
BRCA1/2 mutation was 40% and
11% respectively, for those with
gBRCAmut
1. Davies et al., (2001)
2. Antoniou et al., (2003)
3. Risch et al., (2001)
There is evidence of age discrepancy for onset of disease;
BRCA1 mutation – Increase risk after 40 years old
BRCA2 mutation – Increase risk after 50 years old
This become important when counselling patients regarding options for risk
reduction
7. Implication of BRCA testing in ovarian cancer
BRCA mutation testing, provide an opportunity to screen family members
earlier, and in some cases carry out preventative measures to greatly reduce
the risk of developing cancer
Some professional guidelines recommended, BRCA mutation testing and
genetic counselling should be offered in patient with epithelial ovarian cancer
at the time of diagnosis
However, testing for germline BRCA mutations in patients with ovarian cancer
with mucinous, borderline or non-epithelial histology not recommended
because the frequency of BRCA mutations in these group is similar to that in
the general population
1. National Comprehensive Cancer Network (NCCN), (2014)
2. Risch et al., (2006)
9. Role of prophylactic surgery in BRCA mutation
patients for ovarian cancer risk reduction
Prophylactic surgery in patients with gBRCAmut has been shown to be
beneficial in prevention of ovarian cancer
The risk reduction for ovarian cancer is 35–50% with a salpingectomy alone
Patients who were at high risk for a breast or a BRCA-related gynaecologic
malignancy, that chose risk-reducing salphingo-oophorectomy (RRSO), had a
75% decreased risk of developing ovarian cancer following surgery
A large meta-analysis confirmed the significant reduction in ovarian cancer
risk among patients with BRCA who undergo an RRSO
1. Falconer et al., (2015)
2. Kauff et al., (2002)
3. Rebbeck et al., (2009)
10. Oral contraceptives and BRCA mutation carriers
Oral contraceptive pills (OCP) have been studied as a type of
‘chemoprophylaxis’ shows reduction in risk of ovarian cancer by 50%
A meta-analysis confirmed that the benefit of OCP use among patients with a
BRCA mutation may be similar or better than the general population
However, the use of OCP has to be weighed against the risk of or impact on
breast cancer and hormonal manipulation
Whether OCP use increases the risk of breast cancer in BRCA mutation
carriers is conflicting
1. Narod et al., (1998)
2. Moorman et al., (2013)
3. Lee et al., (2008)
11. Treatment consideration in germline BRCA
mutation carriers
Currently, surgical tumor debulking followed by adjuvant chemotherapy
platinum-based and taxane is the standard treatment for advanced ovarian
cancer
BRCA-mutant cells have shown higher response rates to platinum-based
treatment
Therefore, prognosis BRCA1/2 germline mutations were shown to have a
definitive improvement in overall survival compared to patients without a
mutation
For BRCA2 mutation carriers, the mean 5-year overall survival was 52%
compared to 36% in non-carriers
1. Tan et al., (2008)
2. Bolton et al., (2012)
12. PARP inhibitor
Poly (ADP-ribose) polymerase (PARP) is a member of the collection of proteins
that aides in the homologous recombination repair of double-strand breaks of
DNA
In patients with known BRCA1/2 mutations, single-agent treatment with
olaparib showed a 63% clinical benefit. Olaparib are proven, the progression
free survival was 11 months compare with 4 months in placebo group. Hence,
its use in the maintenance setting for patients with recurrent HGSC who are
platinum sensitive
1. Fong et al., (2009)
2. Ledermann et al., (2014)
13. Rucaparib, a PARP-1/2 inhibitor, was tested in a population with recurrent
HGSOC. It was recently approved for use in germline or somatic BRCA
mutation patients who have had ⩾2 lines of therapy
Niraparib is a third PARP inhibitor that involves inhibition of PARP-1, PARP-2,
and PARP-3. Recently approved niraparib to be used in the maintenance
setting for platinum-sensitive HGSOC, regardless of BRCA status
1. FDA grants accelerated approval to new treatment for advanced ovarian cancer (2016)
2. Mirza et al., (2016)
14. Conclusion
Understanding the role BRCA mutations play in the development, treatment
response, and prognosis is an exciting and developing area in the treatment of
ovarian cancer
Identification of a BRCA mutation may not only help the afflicted patient, but
also allows for genetic testing to be performed on relatives, allowing for the
potential to prevent ovarian cancer
PARP inhibition has an opportunity to significantly improve outcomes in
women who harbor germline or somatic BRCA mutations, as well as tumors
that display a high degree of homologous recombination deficiency