Decode ‘those’ genes

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Decode ‘those’ genes

Sunday, 25 September 2022 | HEALTH PIONEER

Decode ‘those’ genes

In a healthy person, BRCA1 (BReast CAncer gene 1) and BRCA2 (BReast CAncer gene 2) are genes that produce proteins that help repair damaged cells. But when these genes carry mutations, they are responsible for higher risk of breast, ovarian, and uterine cancers. At least, five to ten per cent of all cancer cases are estimated to be hereditary. Oncologists tell THE HEALTH PIONEER how the new tool, Genetic Testing, can be used in high-risk hereditary patients, to help them opt for risk reduction surgeries as a preventive measure, screening, and, regular follow-up.

Dr SVS Deo

Head of Surgical Oncology at AIIMS,

Delhi and National Cancer Institute, Jhajjar, Haryana

People having a family history of breast cancer, ovarian cancer, prostate cancer, colorectal cancer, and cervical cancer can undergo this test to know the risk factor. If the test shows a 60-80 per cent risk factor for cancer, then preventive medical care could be started immediately. Available at AIIMS, these simple and affordable genetic tests can detect genetic defects in time. At AIIMS, Delhi we have already conducted 30 risk reduction surgeries in the last few years on patients who were found to be carrying a cancer-causing gene.

Under risk-reducing surgery, a cancer surgeon removes the breasts at risk of cancer and can simultaneously perform breast reconstructive surgery to create new breasts.

None of the patients developed breast cancer or ovarian cancer after risk-reducing surgery. Similarly, women with genetic defects can undergo removal of both the ovaries along with Fallopian tubes after birth. This method is 95 % successful in the prevention of cancer.

 At present, Genetic testing in government settings is only being offered at AIIMS, New Delhi, and at Tata Memorial, Mumbai, at a cost of Rs 15,000 per test.

Breast cancer is the most common cancer among women in India:  a 40 % increase in breast cancer cases has been witnessed over the last 20 years. As many as 1.5 lakh new breast cancer cases are diagnosed in India every year.

Lack of awareness about these cancers among doctors and the general public, limited availability of genetic counselling and testing services, and reluctance to avail these services are major roadblocks to preventive health care in cancer treatment.

 

Dr Sushma Bhatnagar

Chief IRCH and National Cancer Institute (NCI)  AIIMS,

Jhajjar, Haryana

Women with hereditary gynecological cancers are more worried about the fate of their babies in the future. If yes, what they should do? At our Jhajjar institute, we already have a dedicated infrastructure and a dedicated team of experts and researchers to work in this area as pre-test counseling and post-test counseling are very important.

Within a year or two, we will be ready with a detailed educational draft guideline to help the family members, including sisters and daughters of the patient know about the genetic testing, their risk of developing breast or ovarian cancer and whether they should or not go for this test. As this is a relatively new and fast emerging field in oncology, the draft guidelines will also have various modules focussing on increasing awareness among doctors, patients, and the public.

 

Dr Ranjit Manchanda

Consultant Gynaecological Oncologist at Barts Health NHS Trust, and Clinical Senior Lecturer at Queen Mary University of London

Technology to undertake gene testing on a large scale is now available and needs to be used more for cancer prevention. Identification of women

harboring genetic mutations that cause cancer, not only allows their optimum treatment with newly available drugs but also helps identify unaffected at-risk relatives who can then access

screening and preventive strategies.

Ovarian cancer (OC), breast cancer (BC), endometrial cancer (EC), and colorectal cancer (CRC) account for approximately 50% of cancers in women.

There are several effective preventive therapy options like risk-reducing surgery (mastectomy, risk-reducing salpingo-oophorectomy (RRSO) or hysterectomy), chemoprevention (e.g. aspirin or selective estrogen receptor modulators), and screening for women at high risk of breast cancer or CRC to reduce these CSG carrier-associated cancer risks.

In fact, changing the

paradigm to population testing can address the limitations in the current clinical genetic testing model for CSGs across healthcare systems. It also provides a forward-looking strategy to maximize precision prevention.

Precision prevention encompasses a prevention strategy that incorporates individual variation in

genetic, epigenetic, and non-genetic (environmental, hormonal, reproductive, and lifestyle) factors.

 

Dr Neerja Bhatla

Professor & Head, Obst & Gynaec & WHO CCR, AIIMS, Delhi. Head, Gynae Oncology NCI, Jhajjar, AIIMS

Genetic testing aids in revealing the risk of types of cancers for a woman carrying the mutation. If a breast cancer patient is found carrying a cancer-causing gene, she can be advised to have regular check-ups for the timely detection of potential cancers. They have options of having risk-reduction surgeries in which we remove the normal organ of the patient after the genetic tests reveal the organ is at high risk of malignancy. These tools may also help the patients learn how to manage their risks with personalized cancer screening, and identify preventive steps that they can take to reduce the cancer risk. Those expecting a baby can look for oncofertility.

 

 

Dr Vaishali Sharma

Senior Gynaecologist, Laparoscopic Surgeon, and Infertility Specialist

Genetic Tests is usually helpful in cases of couples with recurrent miscarriages, a family history of any genetic diseases, or when a woman's age is more than 40 years. There are many types of genetic tests ranging from basic karyotype to detailed whole exom microarray. When only a number of chromosomes or any major genetic abnormalities are suspected, then we do karyotype. In cases where we are looking for any specific genetic disease localized to a specific gene on any chromosome, we go ahead with detailed genetic tests like Microarray.

In cases where there is a known genetic disease in the family,  we do a PGD (Pre-implantation Genetic Diagnosis) test in the embryo before transferring it inside the woman's womb. In cases where there is a higher risk of genetic diseases due to the woman's age or history of previous pregnancies with a genetic diseases like Down's Syndrome, we do PGS (Preimplantation Genetic Screening) test.

 

 

Dr Rajiv Sarin

Professor of Radiation Oncology & In-Charge Cancer Genetics Unit at Tata Memorial Hospital & Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Mumbai Tata Memorial Hospital, Mumbai

Our country reports over 15 lakh cancer cases annually of which more than half are women. About 5% of all breast cancers, 20% of all ovarian cancers, and 5% of all endometrial cancers are hereditary or genetic in nature. At the Tata Memorial Hospital, we now register 1,200 families with hereditary cancer every year, and a third of these families have breast, ovarian or uterine cancers.

There are several good private labs in the country that provide high-quality and reliable genetic testing, but the cost, ranging from  Rs 5,000 - Rs 40,000 is unaffordable for many families. We at TMC have provided free testing under research funded by the Indian Council for Medical Research to a few thousand families so far. The country urgently needs many more counselors, oncologists as well as geneticists with expertise in handling hereditary cancer in families.

The cost of genetic testing also must be reduced for it to become more accessible to people.

 

Dr Neena Malhotra

Head, IVF Unit AIIMS, Delhi

Genetic testing has significant importance in preserving childbearing function as these women are young and keen to have pregnancies. The cancer treatments lower the childbearing potential but with advancements in the field of IVF, it is now possible to share their gametes prior to treatment and freeze them to be used once treatment is over.

Genetic counseling before genetic testing for hereditary breast and ovarian cancer is important to determine whether you and your family are likely to have a mutation that is worth getting tested for. Usually, genetic testing is recommended if you have:

 

n A strong family health history of breast and ovarian cancer.

n A moderate family health history of breast and ovarian cancer, and are of Ashkenazi Jewish or Eastern European ancestry.

n A personal history of breast cancer and

meet certain criteria (related to the age of diagnosis, type of

cancer, presence of certain other cancers or cancer in both breasts, ancestry, and family health history)

n A personal history of ovarian or fallopian tube cancer, or primary peritoneal cancer

n A known BRCA1, BRCA2, or other inherited mutation in your family

 

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