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Thanks to genetic tests, it is possible to check the risk associated with the incidence of certain diseases. However – as geneticists themselves emphasize – many questions still remain unanswered. Nevertheless, genetic counseling centers are growing like mushrooms after rain. Is it worth checking your genes?
– Genetic tests are becoming more and more available and are part of the risk assessment of developing malignant neoplasms – says Dr. Dorota Nowakowska from the genetic clinic at the Warsaw Oncology Center. “However, in most patients, the cause of cancer is mutations in genes that we cannot identify. Therefore, only those people with a family history of genes with strong predisposition to the disease should be referred to the examination. A different opinion is shared by the national consultant of oncological genetics, prof. Jan Lubiński. He believes that genetic tests are used far too rarely in Poland, because high-risk mutations occur in as many as half of the cases without prior family history of cancer.
Cancer test
Mutations of several dozen different genes may be responsible for the disease of a given type of cancer. The tests available at the clinics are designed to detect gene mutations that give a very high probability of developing cancer. However, only 5 to 10 percent. malignant neoplasm has strong hereditary conditions. In the remaining 90-95 percent. cancer is caused by both genetic and environmental factors. Hereditary neoplasms include cancer of the breast and ovary, adrenal glands, colon, thyroid and eyeball. Mutated genes can increase the risk of breast cancer 10 times, and ovarian and colorectal cancer up to 40 times.
When to do a genetic test for cancer
Some specialists believe that only a small number of high-risk groups should be genetically tested, others would test everyone.
According to Dr. Nowakowska, the tests should be carried out by people who have had three cases of the same type of cancer in the family in several generations, and one of them before the age of 50. An indication is also one of the closest relatives contracting cancer at a young age, e.g. colorectal cancer or cancer of the endometrium before the age of 45, and breast cancer before the age of 40. A person with a family history of cancer should also be examined. more than one cancer, e.g. breast cancer and ovarian cancer, or bilateral breast cancer. – Indications for testing the carrier of the mutation responsible for breast cancer are basically every patient suffering from ovarian cancer, regardless of family history, and every patient diagnosed with breast cancer before the age of 40 – explains Dr. Nowakowska.
Program of the Ministry of Health
In Poland, there are oncology clinics that, under the program financed by the Ministry of Health, carry out genetic tests aimed at earlier detection of cancer or precancerous lesions in people at the highest risk. In order to qualify for the program, you must complete a special questionnaire available on the website www.genetyka.com. The questionnaire must be sent by post to one of the 20 genetic clinics. You can also find a list of them on this website. A few weeks later, you should call the clinic to find out if you have qualified for the program. If so, we can arrange a consultation, during which our previous health and family history will be analyzed. In justified cases, the doctor will take blood from the patient in order to perform genetic tests. You can wait for the result from 30 days to several months. People who are detected with dangerous mutations are placed under a care program.
Interpretation of the results of genetic tests
– It should be emphasized that in most cases a negative genetic test result is not the same as finding a low risk of cancer – emphasizes Dr. Nowakowska. – If such tests are performed in private clinics, often the result is obtained without medical interpretation and consultation. As a consequence, it may lead to the abandonment of preventive examinations, which may endanger the health and life of patients. People with a positive result, apart from being included in the care program, sometimes require psychological help, and always talks about the risk of developing malignant neoplasms – the doctor explains.
Cancer prophylaxis
Carriers of the mutation responsible for breast cancer cases have regular imaging tests, especially magnetic resonance imaging. After the age of 35 and having completed maternity plans, a significant number of patients decide to remove the ovaries and fallopian tubes, which so far is the only sure method of preventing ovarian cancer in this risk group.
Patients who are diagnosed with an increased predisposition to developing colorectal cancer and their family members undergo colonoscopy every 12-18 months, and in the case of finding lesions, they are referred for colon removal. In these patients, only prophylactic surgical treatment avoids colorectal cancer.
Another group of patients are patients with Lynch syndrome, whose lifetime risk of developing colorectal cancer exceeds 70%. They undergo colonoscopic examinations with procedures for the possible removal of polyps of the large intestine (which are precancerous lesions) at intervals of about two years. By doing so, most Lynch patients can avoid developing colorectal cancer.
Prevention of neoplastic diseases
– Despite the enormous progress, knowledge about predisposition genes remains incomplete, genetic research still requires a significant outlay of financial resources and is labor-intensive, and it will probably take many years to develop cost-effective and fully reliable techniques for examining the entire genome – believes Dr. Nowakowska. Therefore, not genetic tests, but preventive control are still the best method of cancer prevention.
In the field of cancer treatment in carriers of mutations of genes responsible for breast cancer, one can allow for some optimism. The community of clinical oncologists hopes for the final of clinical trials with the use of new generation drugs, particularly effective in carriers of this mutation, says Dr. Nowakowska.
Text: Halina Pilonis