Cancer Risk in Twins | Health Blog

Date: 01/23/2016    Written by: Beth Levine
Cancer Risk in Twins | Health Blog

Family Cancer Risk

In science, one of the most debated topics is nature versus nurture. There are conflicting beliefs as to whether it is our genetics or our environment that most influences our health, disease risk, and nearly everything about us. To make matters more confusing, there is evidence supporting both sides of this issue. Now, to add to this collective body of evidence, is research on twins that suggests a strong association between heredity and cancer.

The study, which was conducted at the Harvard T.H. Chan School of Public Health in Boston, Massachusetts, found that when an identical twin receives a cancer diagnosis it somewhat raises the other twin's chance of developing not only that form of cancer, but any form at all of the disease, weighing in heavily for families' shared risk due to genetics.1 The subjects were more than 200,000 twins residing in Norway, Sweden, Denmark, and Finland who took part in the Nordic Twin Study of Cancer. The twins were tracked for a median of 32 years between 1943 and 2010.

Both identical and fraternal twins were included in the investigation since identical twins share exactly the same genetic material, but fraternal twins only share approximately half the same genes on average--no closer genetically than any other siblings. Over the course of the study period, 32 percent of the volunteers developed some type of cancer.

While twins are generally no more likely to develop cancer than anyone else, a significant difference was discovered between identical and fraternal twins' risks once cancer was diagnosed in one of them. If an identical twin developed cancer, the other twin was shown to have a 14 percent higher risk of being diagnosed with some form of the disease than that of the general population. In contrast, a cancer diagnosis in a fraternal twin only raised the cancer risk in the other twin by five percent. The difference between them, nine percent, represents the increased risk. Although nine percent is certainly not a sure thing, it is a bump in risk that clearly points to a genetic role.

But not all cancers appear to be equally heritable. To determine whether there were some cancers more heavily influenced by genetics than others, the scientists analyzed 23 various types of cancer to determine the impact of genes on risk for each. They reached the conclusion that overall, approximately one-third of our cancer risk is based in our genes. But in certain types of cancer, the influence was much greater. One of the most pronounced genetic effects was noted in testicular cancer, for which the research showed a man has 12 times the risk if it is diagnosed in his fraternal twin and 28 times the risk if this disease is diagnosed in his identical twin.

Genetics were found to play a large part in melanoma, with an increased risk of 58 percent, prostate cancer at 57 percent, and other forms of skin cancer at 43 percent. There was a considerable genetic role seen in other cancers, including ovarian at 39 percent, kidney at 38 percent, breast at 31 percent, and uterine at 27 percent increased risk. Less influence on cancer risk was discovered in lung cancer at 18 percent, colon cancer at 15 percent, rectal cancer at 14 percent, and head and neck cancer at nine percent.

Ultimately, these findings serve as a good reminder that those of us with a family history of certain cancers need to make sure we stay on schedule for check-ups and any necessary testing. But we also need to focus on the other essential elements that affect cancer risk, family history or not, and those are diet and environment. Every single one of us should be striving toward eating a more nutritious diet, exercising daily, quitting smoking (for those who still have this habit), losing weight if necessary in order to optimize our health and reduce our risk of developing cancer and a range of other conditions--and detoxing regularly to remove any environmental triggers before they have a chance to damage DNA.

  • 1. Mucci, Lorelei A.; et al. "Familial Risk and Heritability of Cancer Among Twins in Nordic Countries." Journal of the American Medical Association. 5 January 2016. Accessed 13 January 2016. http://jama.jamanetwork.com/article.aspx?articleid=2480486

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Comments

  •  
    Submitted by Dr.P.K.Chhetri on
    January 28, 2016 - 9:20am

    Cancer: Is it fully curable?

    Cancer is one of the major causes of mortality in the world. It is still a least understood disease. It is estimated that cancer would become a leading cause of death in the world in the 21st century, unless a specific breakthrough is made in the matter of treatment in the medical science. Malignancy is quite common in one-third of population as per the present statistics, though it may vary with age, sex, and geography in the incidence of the various types.
    Malignancies are the result of mutations in the DNA of at least one cell. Normal cell has its own life cycle – it grows, becomes old and ultimately dies the way it has been programmed, but the cancer cell does not die a normal death, it grows and replicates, till the host’s body is unable to cope up with its unfettered replication and finally manifests the signs of lethargy and becomes diseased and collapses. Very simple indeed to decipher, but in the process a precious human life is lost, because the malignant cells have the potentiality to invade locally and beyond its normal tissue boundaries, which is called metastases. Therefore, the cancer cell has a special property to spread and invade, but even then malignant cells retain their phenotype characteristic of their original tissues. For this reason, different types of cancer, such as, lymphoma, sarcoma and breast-cancer, behave on their own characteristic manner.
    Cancers that develop in the epithelial tissues are called carcinomas, whereas those originate in non-epithelial tissues are characterized as sarcomas. We in the body carry tumour-suppressor gene (TSG), but due to some unknown causes these TSGs are inactivated, and a genetic change occurs with malignancy, which in medical parlance is called activation of proto-oncogene. Cancer does not develop overnight; in fact, it takes the route of many mutations in the form of derangements in a variety of gene products. A lot of alterations take place in the epithelial tissues. From hyperplasia to adenoma to dysplasia to carcinoma, the last one is highly dangerous and fatal. We know about possible carcinogens, such as, tobacco and tobacco products including cigarettes, automobile exhausts, nuclear radiation, ultra-violet rays, X-ray, benzopyrene, some hormone-preparations, colouring agents and some second class preservatives in food items, alcohol, meat-diet et al., but in exceptional cases cancer may also occur due to errors in DNA replication, which phenomenon is still not being very clearly understood by the scientists.
    Carcinogens are instrumental in damaging the functional configuration of DNA molecules – they may include strand breakage (single or double), base alkylation, base hydroxylation, chemical formulation, DNA-protein or DNA to DNA cross-linking etc. Cigarette smoke and chewing raw or processed tobacco can cause irreversible damage to DNA molecules and their TSG in tissues of the lung, tongue, lining of the mouth, larynx and oesophagus, thereby triggering the onset of cancer in these organs. Ten out of ten smokers are at risk, but time-limit varies. Passive smokers are also equally at the risk, but who cares? This is the irony of life! This has been the frequent complaint of my ladies patients about their smokers’ husbands. It is said, a smoker kills himself and ten others, who are very close to him. Five to fifteen years are enough to develop the disease, if not luckily, then he will definitely develop high blood pressure, liver disease, blood-related problems, parkinsons disease, dementia etc., the list is endless. Smokers and tobacco-chewers always express their helplessness in kicking-off the habit, but it depends upon one’s own will-power, it should always be ‘now or never’, but never should it be prolonged for tomorrow, because tomorrow never comes, it is always today! Under my coaxing, I have observed people, including my father, giving-up years of smoking habit instantly. So, I do not believe, if someone tries to convince me that he is unable to do it. Therefore, either he is himself unwilling or lacks adequate will-power to act. Unfortunately, both my maternal grand-parents died of oesophagial cancer, because they could give-up the habit of smoking despite constant persuasion from everyone in the family. I still shudder, when I try to recall their painful last moments and immense suffering.
    Be that as it may, similarly, X-rays, ultra-violet rays, nuclear radiations, benzene, benzopyrene (a polycyclic aromatic hydrocarbon found in tobacco-smoke), automobile exhausts, factory releases etc. may also trigger various types of cancers including leukemia.
    Cancer of cervix in women is basically related to human papilloma virus (HPV). Indian women are more prone to this disease because of lack of awareness. Though sub-types of HPV, such as HPV-6 and HPV-11 are associated with cervical neoplasias and benign warts, yet HPV-16 and HPV-18 are high-risk viruses which co-exist with cancer of cervix and malignant lesions. Even recently it has been detected that high-protein (meat) diet, poultry birds, which very often are injected with highly carcinogenic dyes and hormones, and their eggs, and foods cooked in aluminum utensils also carry risks allied with different kinds of cancers including colon and rectal. This apart, grilled and smoked meat is also not free from cancer risk, but who listens? People rush to the doctors after cancer has flared-up, but then it is too late. Death-knell is sounded, once cancer signs are manifested in the system. A wise man never takes the risk. It is better to survive on natural food and pollution-free environment than to take uncalled for hazards in the body. So far every patient came to me with cancer, I have always advised to introduce certain changes in his or her food habits as a first precondition before starting any treatment, and secondly to give-up all risk-associated habits.
    The growth of cancerous cells is always uncontrolled, and they are characterized by the capability to invade the adjacent tissues and transfer them to different locations of the body. Cancer does not develop easily before it passes through different stages. At the early stage, they are practically benign, such in the form of dysplasia, leukoplakia, polyp mainly in colon, fibroid tumour in uterus, prostatitis etc. They always develop from Stage-0 then make progress to Stage-4 and beyond. At the early stage, it is mostly neglected by the patient before it develops into full-fledged cancer. When either in Stage-3 or Stage-4, metastatic process invariably starts, or body’s other parts become gradually invaded. At this stage, treatment always fails. So, it is better, not to neglect even smallest of the symptoms. No pain, howsoever light, or inflammation is without a cause, it should be observed seriously. The greater the concern is displayed, the greater are the chances of recovery, which is the prime mantra for survival.
    Treatment fails due to the onset of metastatic process. Even if primary lesion is removed, cancer is not cured. This is the main drawback of surgical treatment, because of the metastatic deposits, which are carried to different parts of the body by blood. Allopathy does not have any antidote to contain this trait of cancer; therefore, failure rates mount in cancer treatment. Even radical surgery fails to restrain the disease process, when together with the tumour, the suspected surrounding tissues are also excised. The same result is observed in the case of radiotherapy. The primary weapon with an oncologist is the chemotherapy, but this also fails in the long run. Prima facie it seems, chemotherapy has controlled the dissemination of disease in the primary stage, but very often its toxic effects in human body give rise to plethora of adverse side-effects, which become very difficult to subdue. It is not unlikely; the patient may face multi-organ failure in course of time due to mounting toxicity. Therefore, either this way or that way, death is hastened. The common sites of metastasis are:
    From lungs cancer can spread to brain, liver, and gall-bladder;
    Breast to lymph-nodes;
    Naso-pharangeal carcinoma to lymph-nodes on the neck;
    Cervix cancer to uterus and ovaries, and so far and so forth. But these are only the possible sites, but it does not mean they do not spread to other sites.
    Therefore, in any suspected case of cancer, one has to immediately opt for the appropriate tests, for instance, mammography for breast, cervical smear for cervix, endoscopy for gastric, faecal occult-blood and single flexible sigmoidscopy for colon and serum prostate-specific antigen (PSA) for prostate. Besides, for liver and other abdominal organs and brain, routine ultrasonography of whole abdomen and CT scan can be advised, coupled with in selected cases also FNAC.
    One should immediately consult a doctor, if one of the following symptoms persists for sometime or more:
    a)Changes in the bowel or bladder habits; b)Non-specific diarrhea, constipation coupled with grey or black-stool; c)Frequent urination or painful urination; d)An incorrigible ulcer or sore on the skin; e)Non-specific bleeding or discharge from nose, mouth, skin, nipple or vagina; e)Palpable lump in the breast or elsewhere in the body; f)Difficulty in swallowing or ingestion or non-specific persistent pain in the abdominal region; g)When changes occur in the colour, size and shapes of moles or warts; and, h)Continuous hoarseness in the voice or nagging cough or blood expectoration.
    Almost ninety percent of patients die within five years of diagnosis. The failure rates in modern therapies are more or less cent percent, if a patient is keenly observed and pursued for a long period. Usually this is not being done. Hardly only in one or two percent cases is monitoring possible, otherwise clinics or treatment centres are constantly being changed according to financial affordability or as per the whims of the patient’s relatives. Therefore, obviously difficulty is being faced to ascertain the exact cause of death or the prolongation of a patient’s life after the detection of cancer.
    To the alternative systems of treatment patients are brought at the fag-end, when the patients’ conditions have deteriorated passed the benchmark of any hope of recovery. In course of treatment, I have noticed, patients, in most of the cases, have approached me when their every hope of recovery has been shattered. There is nothing such as ‘hope against hope’ also in cancer.
    We are living in the world of pollution – food adulterated, water polluted, and the air which is available free has also been fouled by our idiotic activities. Added to these are our anti-health proclivities. In fact, we are ourselves responsible for inviting cancer in our system. But even then, no disease is incurable, leave alone cancer, if tackled early. However, curability solely depends upon our choice of treatment.
    Cancer is not a local manifestation as it is figured out in allopathy, it is a constitutional malady. Therefore, every cancer case must be treated constitutionally, and in a holistic way. Cancer is the result of accumulation of poison in our system. Hence, it is to be aimed at rectifying the whole system, but not excising a particular part or organ or polluting further with toxic drugs.
    Life is a great gift of God; therefore, it should not be extinguished early by our faulty habits. Our body is bound to be afflicted with one or the other disease sometime or other for one reason or another, but there is a cure also. Curability however depends not only on drugs, but on our life-style habits also. I shall conclude here after discussing a recent mouth cancer case.
    About six months’ back, the husband of an oral cancer lady consulted me for her treatment. She was a ‘gutka’(tobacco) chewer for a pretty long time. Though patient was not brought because she was in Bihar, yet hearing her symptoms from her husband, I prescribed some homeopathic remedies with a strict advice to instruct the lady to stop consuming any kind of tobacco preparations. After six months, I heard, though the mouth ulcer had not developed further, yet it was not displaying any kind of remission either. On being probed further, her husband confessed, the lady had not yet abandoned her ‘gutka’ eating habit. With heavy heart, I had to tell him, his wife’s case was an incorrigible one, because I know sometime or other her cancer would flare up, and hence I had to discontinue her treatment. For the same reason, I have also discontinued one mental dementia patient in the mid-way. In case of cancer or any disease, the cooperation of a patient is imperative, if positive result is expected from treatment.

  •  
    Submitted by Judith Fenton on
    January 29, 2016 - 7:56am
    Chester , New Jersey

    Genetics and disease influence are in its infancy. I don't think anyone knows how genetics work because it take many hits on the DNA material to initiate changes that lead to diseases. The environment is key and the food s we eat and the poisons we use have more to do with the rise in cancer and heart problems. My ancestors lived to be very old because they lived in a more pristine environment.

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