Genetic testing and cancer prevention


CANCER is a disease known to have devastating effects on patients and the affected families. Last year, the Cancer Diseases Hospital (CDH) in Lusaka saw 3,000 cancer patients and 40 percent of those had breast cancer. There is also a high mortality rate from breast cancer in Zambia.
In the medical world prevention is often advocated as a better alternative to treatment because the idea is to encourage pro-activity rather than reactivity in health care.
Testing for genetic or hereditary mutations that increase the risk of cancer is one proactive method of cancer prevention widely practised in the developed world.
It is viewed as being important for risk reduction, early detection and choice of treatment.
Consultant clinical oncologist George Pupwe explains that genetic or hereditary mutation means one has a gene mutation which may run in a family from generation to generation either as a dominant or non-dominant gene.
Mutation means a normal cell changes into an abnormal cell due to certain known, unknown factors or natural causes.
It could happen when a normal cell becomes exposed to chemicals, ultraviolet rays or some sort of radiation and undergoes a transformation as a result, turning it into an abnormal cell.
An abnormality in the cell can further transform it into cancerous cells. Dr Pupwe points out that a mutation does not necessarily mean that one will have cancer but puts them at risk.
In one generation the cancer gene can be non-dominant and then become dominant in the next generation and can be one of the causes of cancer.
However, not all cancers carry the risk factor of genetic predisposition, as Dr Pupwe shares.
“Basically the risk factors for hereditary mutations are mostly in cancers such as breast cancer, the most common being the BRCA1 and BRCA2 mutation. This is both in breast and ovarian cancers,” he explains.
He says genetic mutations can also occur in colorectal cancer as well as in prostate cancer which attacks a lot of men over the age of 40.
In children genetic mutations can happen in cancers like retinoblastoma.
Testing for hereditary mutations establishes whether or not there is a strong positive family history of cancer where the disease has attacked members of different generations of the same family.
This is also called Familial Cancer where cancer occurs in families more often than would be expected by chance.
If the test reveals a strong family history, family members who are genetically predisposed are then counselled on preventive measures they can take to avoid getting cancer or reduce the risk of getting cancer.
“Why it is important is because we all know that cancer is curable but it has to be caught early, and early detection or diagnosis gives better treatment outcomes,” Dr Pupwe shares.
While most women are encouraged to start being screened for cancer at 40 years, if one is found to belong to a family where there is a genetic mutation one is advised to start being screened at age 25 instead.
A woman who has had breast cancer and is genetically predisposed, stands a higher chance of having either a recurrence or cancer in the second breast.
Hereditary testing gives people a perspective that helps them understand that they can get the cancer but it can be diagnosed early or they can take out their ovaries and breasts – in the case of breast and ovarian cancer – and not get the cancer.
Because the choice of preventive treatment can involve complex decisions like organ removal, counselling is a huge part of hereditary testing.
“For stage one breast cancer, you would probably just be given surgery upfront, you might not need chemotherapy, and if you’re hormone receptor positive, we’ll give you some hormone therapy. You might not need radiotherapy. So the earlier we catch it, the less aggressive the treatment is,” Dr Pupwe explains.
According to a July 2018 genetic/familial high-risk assessment of breast and ovarian cancer conducted by the National Comprehensive Cancer Network (NCCN), an alliance of 27 cancer centres in the US, all cancers develop as a result of mutations in certain genes.
These genes include those involved in the regulation of cell growth and/or DNA repair, although not all of these mutations are inherited from a parent.
The NCCN risk assessment states that family studies have long documented an increased risk for several forms of cancer among first-degree relatives, (that is, parents, siblings, children) and second degree relatives, (that is, grandparents, aunts or uncles, grand children, nieces or nephews) of affected individuals.
“These individuals have an increased susceptibility to cancer as a result of one or more gene mutations present in parental germline cells; cancers developing in these individuals may be classified as hereditary or familial cancers,” reads the assessment in part.
The NCCN recommends that an individual suspected of being at risk of cancer should be offered genetic counselling.
“Assessment of an individual’s risk for familial or hereditary cancer is based on a thorough evaluation of the personal and family history. The first step in evaluating an individual’s risk for hereditary breast cancer is to assess her/ his concerns and reasons for seeking counselling and to guarantee that her/his personal needs and priorities will be addressed in the counselling process,” states the NCCN.
The NCCN also highlights that a detailed family history is the cornerstone of effective genetic counselling because the magnitude of the risk of one having cancer increases with the number of affected relatives in the family and the closeness of the relationship and is affected by the age at which the affected relative was diagnosed.
The younger the age at diagnosis, the more likely it is that a genetic component is present, explains the NCCA.
Zambian Cancer Society (ZCS) founder and cancer survivor, Udie Soko, shares that the ZCS is concerned about the continued high rate of late presentation of cancer cases in Zambia due to reasons such as stigma, fear of spousal abandonment and damaging myths and misconceptions that cancer is caused by witchcraft and that it is a curse.
These reasons, Ms Soko says, cut across rural and urban, literate and illiterate people. She is therefore sceptical about the willingness of women to undergo hereditary testing in Zambia.
“Hereditary testing may result, for example, in recommending the removal of both breasts or ovaries or the uterus. In our culture these same organs typify womanhood. Therefore, how willing would women be to be tested especially when regular cancer screening evokes fear in a lot of women?” she says.
Healthy lifestyle choices such as avoiding tobacco in all forms, regular exercise, healthy diet and stress reduction are what Ms Soko insists should really be encouraged and prioritised, adding that, “This helps people to feel empowered and take responsibility for their own health. As you may know, one-third of cancers could be prevented through healthy lifestyle choices.”
Deliberate healthy lifestyle policies and campaigns should be ingrained in daily life which would be a pathway to encourage hereditary testing with less resistance, stresses Ms Soko.
Dr Pupwe also emphasises that sensitisation is key in a country like Zambia where some people still hold on to cultural beliefs regarding illness.
“The starting point is first of all educating people because if you are going to start something without education, there will be resistance from people but even when people go through counselling without proper information, it may still cause negative consequences,” he says.
Prevention, he says, is the key in health care and developed countries have invested much money in prevention and awareness, which is cheaper and the best option for societies trying to move away from treatment.
Dr Pupwe is confident that in the not so distant future there can be greater room for hereditary testing to be made a priority in Zambia, especially for people at high risk of getting cancer.

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