What is Hereditary Non-polyposis Colorectal Cancer (Lynch Syndrome)?

Hereditary non-polyposis colorectal carcinoma ( Lynch syndrome ) is a type of colon cancer that is mainly based on hereditary factors and does not form polyps in the intestinal mucosa. The disease, which is also synonymously referred to as Lynch syndrome after the US surgeon T. Lynch, is the most common form of hereditary colon cancer. A total of 6 mutated genes were identified as the cause, which are involved in the repair mechanism of defectively replicated DNA sequences.

What is hereditary nonpolyposis colorectal cancer?

Hereditary non-polyposis colorectal carcinoma ( HNPCC ), also known as Lynch syndrome after the US surgeon Henry T. Lynch, is a colon cancer that is based on previously identified gene mutations and is inherited in an autosomal dominant manner. This means that the gene defect or defects are not located on the two sex chromosomes X or Y and that a mutated allele of a gene (heterozygous) can already cause the disease.

In the case of Lynch syndrome, approximately 75 percent of heterozygous carriers of the mutated genes are affected by the disease. Children of parents whose father or mother are carriers of the gene mutation have a 50 percent chance of also becoming heterozygous carriers of the gene mutation. About 90 percent of all colorectal cancers develop from polypoid tissue via the stage of benign adenomas.

In contrast, hereditary non-polyposis colorectal carcinoma has no connection with any polyps present in the intestinal mucosa. The development of the tumors of Lynch syndrome is exclusively attributed to a loss of function of the repair mechanism for defectively replicated DNA sequences. The probability that other cancers of the intestine or other organs will develop in addition to the HNPCC disease is greatly increased compared to people who do not have HNPCC.

Causes

HNPCC is caused by a defect in the repair mechanism of defectively replicated DNA sequences. The repair mechanism normally prevents replicated DNA fragments with incorrectly occupied nucleobases from being used further. Repair proteins encoded by so-called tumor suppressor genes are involved in the mechanism.

Mutations in several suppressor genes are known, almost always affecting the genes mlh1 on chromosome 3 and msh2 on chromosome 2. If the repair proteins fail, cell mutations accumulate in the formation of new cells, so that defective cells accumulate in clones that behave largely autonomously and no longer react to the usual growth limiters. They typically form the germ cell of a malignant tumor.

Symptoms, Ailments & Signs

The HNPCC causes hardly any complaints and symptoms in the early stages. The first signs, such as blood in the stool, are non-specific and can have various causes. As the disease progresses, phases of constipation and diarrhea alternate. Gradually, abdominal pain, weight loss and signs of anemia appear as typical side effects.

If the lymph nodes of the mesentery, the supporting ligaments of the intestines, also react with swelling and sensitivity to pressure, metastasis of an HNPCC may already have occurred. A demarcation between a non-polypoid HNPCC and a much more common colon cancer with a 90 percent probability, which develops from polyps of the intestinal mucosa, is not easily recognizable in the early stages on the basis of the non-specific symptoms. Only the targeted use of differentiated diagnostic procedures create the necessary clarity.

Diagnosis & History

The causes of HNPCC disease are purely genetic in nature, so that in connection with the autosomal dominant inheritance of the disease, familial statistics regarding HNPCC diseases are used for diagnostic purposes. The so-called Amsterdam I and Amsterdam II criteria were introduced in 1990 to standardize the significance of statistical parameters.

The Amsterdam I criteria can only be used to detect colorectal HNPCC, and the Amsterdam II criteria can also be used to detect carcinomas at other sites within the urogenital tract. The first condition of the Amsterdam Criteria is that at least three family members, one of whom must be a first-degree relative of the other two family members, have proven HNPCC disease.

The second condition is met if the diseases occurred in at least two consecutive generations. The third condition was that one of those affected had to develop the disease before the age of 50. If the family circumstances or the course of the disease are not known, the revised Bethesda criteria were introduced in 2004 for assessment, one of which must be fulfilled in each case in order to justify the suspicion of HNPCC.

After the suspicion of HNPCC has been established, a number of diagnostic options are available to confirm or reject the suspicion. On the one hand, ultrasound examinations and histological examinations are expedient, and on the other hand, molecular genetic examinations that can provide indications of the presence of mutated suppressor genes. If left untreated, the course of the disease is serious.

Complications

Lynch syndrome is a serious illness. If left untreated, this can lead to death and, with treatment, is often associated with a reduction in life expectancy. In most cases, the primary cause of Lynch syndrome is bloody stools. This can trigger a panic attack in many people.

Furthermore, the patients suffer from diarrhea and constipation and thus a reduction in the quality of life. There is weight loss and often severe abdominal pain and anemia. Furthermore, those affected may lose consciousness and even fall into a coma. Swelling and pain appear. If Lynch syndrome is not treated, it will metastasize and thus lead to colorectal cancer.

As a rule, cancer diseases can only be treated well if they are diagnosed early. It is not uncommon for those affected to suffer from depression and other mental disorders in addition to the physical symptoms. The patient’s relatives can also be affected by these upsets. Lynch syndrome can be removed through surgery. However, the further course of the disease depends on the diagnosis and the spread of the tumor, so that a positive course of the disease cannot be predicted in every case.

When should you go to the doctor?

Blood in the urine that occurs repeatedly is a cause for concern. A doctor’s visit is necessary to clarify the causes. If there are any abnormalities in digestion, the symptoms should be examined. In case of diarrhea or constipation, a doctor should be consulted in order to be able to initiate treatment. If the affected person starts to lose weight, this can lead to an undersupply of the organism. It is therefore advisable to have them examined by a doctor in good time.

If you have persistent or regularly recurring abdominal pain or abdominal discomfort, you should consult a doctor. If there are swellings, growths or skin abnormalities, a doctor’s visit is also necessary. If existing symptoms increase or new symptoms appear, this is considered unusual and should be examined. If you experience pain or sensitivity to pressure, you need to see a doctor. A doctor should be consulted in the event of dizziness, a general feeling of illness, nausea and vomiting.

If the sufferer suffers from a decrease in performance, listlessness or weakness, this health condition should be discussed with a doctor. Sleep disorders, concentration problems and attention deficits are complaints that can indicate serious impairments. Therefore, a visit to the doctor is recommended as soon as the person concerned experiences these irregularities over several weeks.

Treatment & Therapy

The only treatment for hereditary nonpolyposis colorectal carcinoma is surgical removal. There is no drug or other treatment that could cure the cancer. It is therefore of great value in terms of a high success rate if an HNPCC that has occurred is recognized and removed as early as possible. In some cases, it may be necessary to perform radiotherapy combined with chemotherapy on the diseased tissue before surgery.

Outlook & Forecast

With early treatment of hereditary non-polyposis colorectal cancer, also known as Lynch syndrome, there is a good prognosis in terms of recovery. However, since there is a hereditary increased risk of colorectal cancer and other forms of cancer, the patient should have constant follow-up examinations for healed colorectal cancer and preventive examinations for other types of cancer.

If the tumor is still limited and no metastases have formed, there is no need for chemotherapy after its complete surgical removal. A normal life expectancy can be assumed if constant follow-up care and precautions are taken.

Not all patients with this genetic defect will develop cancer in the course of their lives. However, the probability is very high. It was found that up to the age of 80, 80 percent of all affected people will develop colon cancer.

If metastases have already developed or if other organs are affected by a tumor at the same time as colorectal cancer, the prognosis often deteriorates drastically. Parallel tumors that have not yet formed metastases can be treated independently of one another and completely healed again.

After metastases have formed, various therapeutic measures such as chemotherapy or radiation can be used to delay cancer growth and prolong the life of the patient. In addition to the known treatment options, psychological care for the patient often contributes to improving the quality of life in severe cases.

Prevention

Preventive measures to avoid HNPCC do not exist because the main cause lies in tumor suppressor genes, which largely lose their ability to repair incorrectly copied DNA sequences due to mutations. In addition, a lifestyle that supports the immune system can also be considered a conditional preventive measure.

The most important preventive measures for people who belong to the group of people at risk because of their family history or because of molecular genetic tests are regular cancer screening such as colonoscopy and other early detection measures.

Aftercare

Follow-up care for hereditary non-polyposis colorectal cancer begins with regular check-ups. These are intended to ensure that the healed colorectal cancer does not recur. If it is a confined tumor without metastases that has been completely removed, these follow-up examinations are just as important. Depending on the severity of the individual case, psychological support can be useful.

This can take place as part of prevention as well as during follow-up treatment. For a good quality of life, it is important to follow the medical advice of the medical professionals. A healthy lifestyle is essential to support the immune system. Above all, this includes a balanced, nutritious diet, often in combination with avoiding certain foods.

If the molecular genetic studies indicate that the risk potential is quite high, cancer prevention is clearly the priority. Patients who are at risk because of their family background should have regular colonoscopy and other early detection measures.

In the case of acute symptoms, there are also home remedies and self-help tips for everyday life. Light food and painkillers on a natural basis reduce the abdominal pain that occurs. If swelling occurs, a gentle massage or a cooling wrap will help. In addition, patients should listen to their doctor and take it easy.

You can do that yourself

Lynch syndrome always requires medical treatment. The acute symptoms of Lynch syndrome can be alleviated by a number of home remedies and self-help measures.

Diarrhea can be reduced by changing your diet, while natural painkillers can be used to treat abdominal pain. In the case of swelling, cooling compresses and gentle massages of the affected areas are recommended. After the carcinoma has been surgically removed, the patient must take it easy and otherwise comply with the doctor’s instructions. In most cases, an individual diet is recommended, consisting of light food, low-salt food and avoiding coffee, alcohol and other stimulants.

Recovery can be aided by taking extra care at the site of the operation. Bleeding and swelling can occur, especially in the first few days. These can be reduced with marigold ointment and preparations with arnica or devil’s claw. Women who have once developed Lynch syndrome should arrange for an early examination of the child during pregnancy. The child should be examined again in detail after birth and must attend regular cancer screenings throughout life.

Hereditary Non-polyposis Colorectal Cancer