hereditary breast and ovarian cancer
hereditary breast and ovarian cancer
Hereditary Breast and Ovarian Cancer Syndrome (HBOC) is an inherited tendency to develop Breast, Ovarian and other cancers. However, most cancers are not inherited but about 5% of people with Breast cancer and 10% of women with ovarian cancer have HBOC. Cancer is as a result of an uncontrolled cell division caused by mutations or abnormal activation of the genes which control cell division. There are about a hundred known abnormal genes called Oncogenes (Onkos means tumor). Cancer is a complex group of diseases affecting a wide range of cells and tissues. Most cancer mutations occur in the somatic cells and are not passed on to future generation.
Only about 1% of cancer germline mutations is transmitted to offspring and can cause cancer susceptibility. There are over 200 types of cancer.
BRCA1 and BRAC2 are human genes that belong to a class of suppressors, they are genes linked to hereditary breast and ovarian cancers. In a normal cell BRCA1 and BRCA2 help to ensure the stability of the cell’s genetic material DNA and help prevent uncontrolled cell growth. The name BRCA1 and BRCA2 stand for breast cancer susceptibility gene 1 and 2 respectively.
BRCA1 is a gene found on chromosome 17, an autosomal dominant trait which is associated with a predisposition to breast cancer. In about 85% of women with one mutant BRCA1 allele, a mutation in the second BRCA1 allele occurs and this can lead to breast cancer in such women with risk of ovarian cancer and
the second breast cancer gene BRCA2 is located in the chromosome 13, associated with predisposition to breast cancer but not ovarian cancer. The two genes are located in the nucleus where they encode large proteins and their expressions occur highest during S phase. They are involved in DNA repair and regulation of cell cycle and transcription Hereditary breast and ovarian cancer syndromes (HBOC) produce higher than normal level of breast and ovarian cancer in genetically related families (either one individual suffered from both or several individuals in the pedigree suffered from one or the other disease).
Overall, it has been estimated that inherited BRCA1 and BRCA2 mutations account for 5 to 10 percent of breast cancers and 10 to 15 percent of ovarian cancers among white women in the United States (Campeau et al., 2008). A significant portion of hereditary breast cancers are not associated with BRCA1 or BRCA2 mutations (Lynch et al., 2008). Furthermore, from the studies made with 434 Nigerian breast cancer patients from the University College Hospital in Ibadan, it was gathered that Nigerian breast cancer patients have an exceptionally high frequency of BRCA1 and BRCA2 mutations (7.1 and 3.9%, respectively) (www.brcascoop.com).
CANCER RISK FOR PEOPLE WITH HBOC
Causes of HBOC: It is cause by inherited changes in gene known as mutation. For it to occur, the gene wall stops working normally i.e. genes responsible to prevent breast and ovarian cancers. It is mostly due to mutation in either BRCA1/ or BRCA2 genes.
- Chances of inheriting HBOC: Individual person has two copies of all genes, including each of the BRCA genes. One copy each is inherited from both parents. Therefore there is a 50% chance of a person with HBOC to pass the mutation gene to offspring. Inheriting this mutation gene causes high risk for several types of cancers.
- If a person does not inherit the mutation, there is still 12% general population life risk developing breast cancer and 1 to2% risk of developing ovarian cancer.
Cancer risks for women with HBOC
Lifetime risk of breast cancer 50% to 85%
Risk of breast cancer before age 50- 30% to 50%
Lifetime risk of ovarian cancer
BRCA1 gene mutation 25% to 40%
BRCA2 gene mutation 15% to 27%
There is also an increased risk of a second breast cancer diagnosis.
Cancer risks for men with HBOC
Lifetime risk of breast cancer
BRCA1 gene mutation some increased risk
BRCA2 gene mutation up to 6%
Risk of prostate cancer
BRCA1 gene mutation some increased risk
BRCA2 gene mutation up to 20%
Men with a BRCA2 gene mutation have a significantly increased
risk of developing prostate cancer before age 65.
UNDERSTANDING BRCA GENES
- BRCA are genes that protect you from getting certain cancers. Women with inherited change in BRCA1/2 genes have a high risk of developing breast and ovarian cancer. Steps can be taken to lower the risk for these women.
HOW IS HBOC SYNDROME INHERITED
Since BRCA1/2 controls the cell growth and division, when there is mutation in these genes; there is tendency for cancer to develop.
Autosomal Dominant Inheritance of Breast/ Ovarian Cancer Predisposition
This is characterized by transmission of cancer predisposition from generation to generation, through either the mother’s or the father’s side or the family with the following characteristics.- Inheritance risk of 50% and Both males and females can inherit and transmit an autosomal dominant cancer predisposition.
Breast and ovarian cancer are components of several autosomal dominant cancer syndromes
- The syndromes associated with both cancers are BRCA1 or BRCA2 mutation syndromes.
- Breast cancer is a common feature of L1- Fraumeni syndrome due to Tp 53 mutations and of Cowden syndrome due to PTEN mutations.
- Other genetic syndromes that may include breast cancer as an associated features include heterozygous carriers of the ataxia telangiectasia (AT) gene and Peutzjeghers syndrome.
- Ovarian cancer has also been associated with Lynch syndrome, basal cell nervus (Gorlin) syndrome (OMIM) and multiple endocrine neoplasia type1 (MEN1) (OMIM).
- In 2012, an estimated 226,870 women in United States will be diagnosed with invasive breast cancer and 63,300 women will be diagnosed with in situ breast cancer.
- An estimated 2,190 men in the United States will be diagnosed with breast cancer.
- It is estimated that 39,920 deaths (39,510 women and 410 men) from this disease will occur this year.
- Breast cancer spreads when cancer cells move to other parts of the body through blood vessels known as metastasis. It spreads commonly to the regional lymph nodes which can be axillary (under armpit), cervical (neck) or supraclavicular (collar bone). It can spread further to the bones, lungs and livers. Less commonly, it can spread to the brain.
- Breast cancer can reoccur after treatment locally in the skin, the same breast, and other tissues of the chest or elsewhere in the body. BRCA1 is a gene found in chromosome 17, an autosomal dominant trait which is associated with a predisposition to breast cancer. In about 85% of women with one mutant BRCA1 allele, a mutation in the second BRCA1 allele occurs and this can lead to breast cancer in such women. Also there is a risk of ovarian cancer.
- The second breast cancer gene BRCA2 is located in the chromosome 13, associated with predisposition to breast cancer but not ovarian cancer. The two genes are located in the nucleus where they encode large proteins and their expressions occur highest during S phase.
TYPES OF BREAST CANCER
. Lobular Carcinoma
.Invasive or Infiltrating lobular Carcinoma
When the disease is not spread, it is called in situ meaning “in place” depending on whether it is ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS)
OTHER BREAST CANCER
less common cancers of the breast include medullary, mucinous, tubular, metaplastic, and papillary breast cancer. Inflammatory breast cancer is faster- growing type of cancer that accounts for about 1% to 5% of all breast cancers. It may be misdiagnosed as a breast infection because there is often swelling of the breast and redness of the breast skin. Paget’s disease is a type of cancer that begins in the ducts of the nipple. The skin often appears scaly and may be itchy but usually in situ and can be an invasive cancer.
SIGNS AND SYMPTOMS OF BREAST CANCER
- New lumps that feel like a hard knot (many women normally have lumpy breasts) or a thickening in the breast or under the arm.
- Nipple tenderness, discharge (may occur suddenly be bloody, or occur in only one breast), or physical changes (such as a nipple turned inward, a persistent sore, or a change in the size or shape of the breast).
- Skin irritation or changes, such as puckers, dimples, scaliness, or new creases.
- Warm, red, swollen breasts with a rash resembling the skin of an orange (called peau d'orange).
- Pain in the breast (usually not a symptom of breast cancer, but it should be reported to a doctor), particularly breast pain that doesn’t go away.
- Personal history of breast cancer
- Family history of breast cancer
- Genetic predisposition
- Personal history of ovarian cancer
- Estrogen and progesterone exposure
- Postmenopausal hormone replacement therapy
- Oral contraceptives (birth control pills)
- Race and ethnicity
- Atypical hyperplasia of the breast
- LCIS (lobular carcinoma in situ)
- Lifestyle factors
- Breast density
DIAGONOSIS AND SCREENING OF BREAST CANCER
Many tests are used to diagnose cancer and find out if it has spread.
- IMAGING TEST
- TESTING THE TISSUE
- Testing a tumor’s genes
- BLOOD TESTS
- Additional tests
PREVENTION OF BREAST CANCER
There are no 100% intervention/ guaranteed prevention on breast cancer, depending on a woman’s specific risk factors, there are options to reduce the risk of breast cancer development such as;
1. women with BRCA1/2 mutation, may consider prophylactic mastectomy
2. Those with higher risk of developing breast cancer may consider chemoprevention
3. Getting regular physical activity, staying at a normal weight and limiting the amount of alcohol intake.
Treatment of breast cancer
- Radiation therapy
- Targeted therapy
- Hormonal therapy
- Tamoxifen can be used to block estrogen from binding to breast cancer cells. It is effective for reducing the risk of recurrence in the breast that had cancer, the risk of developing cancer in the other breast, and the risk of distant recurrence.
- Cancer and its treatment can cause a variety of side effect ranging from pain, nausea and vomiting, infection, fatigue, and other physical side effects. Other side effects are palliative or supportive care (care of a person’s symptoms and side effects), care giving and sexual health.
- However, many treatments used today are less intensive but equally effective as or more effective than treatments used in the past.
- Ovarian cancer begins when normal cells in an ovary change and grow uncontrollably forming a mass called a tumor. This tumor can be benign (non-cancerous) or malignant (cancerous).
- An ovarian cyst is different from non-cancerous tumor and it usually go off without treatment (thus not cancerous).
- It is estimated that in this year about 22,280 women in the United States will be diagnosed with ovarian cancer, 15,500 death recorded from this disease this year.
- About 3% of women with cancer have ovarian cancer and it is the fifth most common cause of cancer- related death in women.
- The one-year survival rate of women with cancer shows that 75% survived. Five- year survival rate is 44% but if the cancer is diagnosed and treated before it has spread outside the ovaries, we have 93% five year survival rate but when it has spread to the surrounding organs or tissue the five- year survival rate will reduce to 72% and if it has spread to other parts of the body far away from the ovary (distant spread), the five- years survival rate will drastically reduce to 27%.
- Note that the actual; risk for individuals differs.
Three types of ovarian cancer
- 1. Epithelial carcinoma: it makes up 85% to 90% ovarian cancers and begins at the cells of the outer surface of the ovary.
- 2. Germ cell tumor: it is uncommon type of tumor which develops in the egg- producing cell of the ovaries and is common between women of 10 to 29 years.
- 3. Stromal tumor: a rare form of ovarian cancer which develops in the connective tissue cells that hold the ovaries together and make female hormones.
- Taking Birth Control Pills
- Breast Feeding
SIGNS AND SYMPTOMS
bloating, pelvic or abdominal pain, difficult eating or feeling full quickly, urinary symptoms (urgency or frequency).
- fatigue, indigestion, back pain, pain with intercourse, constipation, menstrual irregularities etc.
Please note that these signs and symptoms may also be caused by a medical condition that is not cancer. Also some women with ovarian cancer may not have these symptoms.
- DIAGNOSISFactors to consider when choosing a diagnostic test for ovarian cancer are;
- a. Age and Medical condition
- b. Type of cancer suspected
- c. Severity of symptoms
- d. Previous test results.
Other test uses to detect ovarian cancer
- Transvaginal Ultrasound
- Pelvic examination
- CA- 125 assay
- Lower Gastro Intestinal (GI) Series
- Computed tomography (CT or CAT) Scan
- Positron Emission Tomography (PET) Scan
- Treatment options by stage
- Surgery and chemotherapy
- Stage II
- Stages III & IV
- Surgery and chemotherapy (either IV or IP or both combined)
- Hereditary breast and ovarian cancer syndrome (HBOC) is an inherited tendency to develop breast, ovarian or other cancers.
- About 5% of people with breast and 10% of women with ovarian cancer have HBOC.
- This is as a result of inherited changes in gene known as mutation. People with changes in the BRCA1/2 gene have a high risk of developing breast or ovarian cancer.
- This autosomal dominant gene can be passed from either of both parent from generation to generation.
- Hereditary breast and ovarian cancer syndrome produces higher than normal levels of breast and ovarian cancer in genetically related families.
- Not everybody with inherited chances in the BRCA1/2 have the tendency of developing breast or ovarian cancer.
- Current recommendation by professional organization is to screen the general population at the primary care level to identify those at potentially increased risk for hereditary susceptibility to breast and ovarian cancer.