Cancer linked to family genetics
Some families carry a genetic mutation passed on from one generation to the next. Heredity accounts for five to 10 percent of all cancer cases. In these situations, a number of indicators can help determine if a genetic mutation occurs within the same family:
- Family members are diagnosed with cancer at a young age.
- Multiple family members are diagnosed with the same or a similar type of cancer.
- A family member has been diagnosed with more than one type of cancer (such as breast and ovarian cancer).
- The cancer occurs in both organs of a pair (such as both breasts, kidneys or eyes).
- Family members have an uncommon or rare type of cancer.
- More than one case of childhood cancer occurs among the same siblings (brothers and sisters).
Smoking, diet and alcohol: Aggravating factors
While a number of cancers are linked to heredity, most are thought to be caused by lifestyle. Research suggests that nearly half of all cases of cancer could be prevented by quitting smoking and alcohol and, more generally, by adopting healthy habits.
Environmental risks harder to calculate
Genetics and precision medicine
Regardless of the cause, cancer has traditionally been treated based on its location in the body (breast, lung, etc.). Nowadays, precision medicine focusses on the cancer’s main characteristics. Since no two people or cancers are identical, why prescribe the same treatment?
As a result, personalized medicine adapts the treatment according to the genetic profile of the individual and their cancer. This makes it possible to mitigate certain side effects while maximizing the therapy’s chance of success. This way, by relying on genetic testing and pharmacogenetics, it is now possible to develop more effective precision drugs that are tailored to the patient’s case.
It is even possible to conduct genetic tests to assess the likelihood of a cancer returning after a treatment, or detect it in its early stages.
Unfortunately, these medical practices remain very expensive. What’s more, precision medicine is sometimes offered only in one-time, limited clinical trials. Nonetheless, this is certainly a major breakthrough in the fight against cancer.
What to remember about the risk of cancer
Over the past few decades, science has made enormous progress in treating and curing cancer. However, we are still struggling to prevent cancer and establish reliable and quantifiable correlations between lifestyle habits and the disease. For example, it is difficult to estimate the number of hours of sun exposure that the skin can tolerate before skin cancer appears, and that number will vary from one person to another.
However, medicine has well identified the main factors likely to increase the risk of cancer, although once again, their impact is not the same for everyone. Here they are classified by category:
Age : Most cases of cancer are diagnosed after age 65. This is because the majority of cases take decades to develop. Cell renewal also decreases with age, thereby protecting the body less effectively against this threat.
Lifestyle habits : The foods we eat and beverages we drink, the cleaning products we use, along with our consumption patterns in general, all have an influence on our health.
Family history : In some families, genetic mutations are conducive to developing cancer. Certain habits, exposure to the sun or toxic products, along with genetic factors shared by multiple members of the same family, can also come into play.
Environment : Living or working near asbestos, for example, can increase the risk.
Health status : Chronic diseases such as ulcerative colitis, hepatitis B or human papillomavirus (HPV) are aggravating factors for some types of cancer.
Ultimately, few types of cancer can be attributed with certainty to genetics or lifestyle. Most likely, cancer results from a combination of these two factors, i.e. a genetic predisposition (other than an inherited mutation) combined with one or more harmful habits.
For this reason, it is important to maintain a balanced diet and a healthy lifestyle to reduce some of the risks. With your doctor’s advice, you can also arrange for examinations, screenings or genetic tests based on your personal history. Vaccination against hepatitis B or HPV can also help prevent the disease.
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- Mayo Clinic. “Cancer,” https://www.mayoclinic.org/diseases-conditions/cancer/symptoms-causes/syc-20370588 (accessed on February 7, 2022).
- Canadian Cancer Society. “Cancer risk in families,” https://cancer.ca/en/cancer-information/what-is-cancer/genes-and-cancer/cancer-risk-in-families (accessed on February 7, 2022).
- Ministère de la Santé et des Services sociaux. “Lutte contre le cancer,” updated on January 21, 2015, https://www.msss.gouv.qc.ca/ministere/lutte-contre-le-cancer/prevenir-le-cancer (accessed on February 7, 2022).
- Canadian Cancer Society. “Precision medicine,” updated in February, 2021, https://cancer.ca/en/research/understanding-cancer-research/precision-medicine (accessed on February 7, 2022).