Hereditary Nonpolyposis Colorectal Cancer

(Lynch syndrome)

Hereditary nichtpolypöse colorectal cancer (HNPCC) is an autosomal dominant disease that is responsible for 3-5% of cases of colorectal cancer (CRC). The symptoms, initial diagnosis and treatment are similar to those of other forms of CRC. HNPCC is suspected on the basis of medical history and confirmed by genetic testing. Patients also require also controls in regard to the occurrence of other cancers, v. a. of endometrial and ovarian cancer.

Patients with a history of several mutations have a lifetime risk of 70-80%, a CRC to develop (Colorectal cancer). Compared with sporadic forms of colon cancer, the HNPCC occurs at a younger age (mid-forties), and the lesion is located with a greater likelihood proximal to the splenic flexure. The precursor is usually a single adenoma, not multiple adenomas as in patients with familial adenomatous polyposis (FAP, familial adenomatous polyposis) occur, the other major form of hereditary colorectal cancer.

Hereditary nichtpolypöse colorectal cancer (HNPCC) is an autosomal dominant disease that is responsible for 3-5% of cases of colorectal cancer (CRC). The symptoms, initial diagnosis and treatment are similar to those of other forms of CRC. HNPCC is suspected on the basis of medical history and confirmed by genetic testing. Patients also require also controls in regard to the occurrence of other cancers, v. a. of endometrial and ovarian cancer. Patients with a history of several mutations have a lifetime risk of 70-80%, a CRC to develop (Colorectal cancer). Compared with sporadic forms of colon cancer, the HNPCC occurs at a younger age (mid-forties), and the lesion is located with a greater likelihood proximal to the splenic flexure. The precursor is usually a single adenoma, not multiple adenomas as in patients with familial adenomatous polyposis (FAP, familial adenomatous polyposis) occur, the other major form of hereditary colorectal cancer. However, numerous manifestations outside of the colon appear similar to as the FAP. Non Malignant changes are café-au-lait spots and sebaceous tumors and keratoacanthoma. In low-gradigem skin cancer a keratoacanthoma may occur. Other common cancers are associated endometrial and ovarian tumors (a risk of 39% for endometrial and ovarian tumors of 9% for up to 70 years). The patients also have an increased risk of cancer of the ureter, the renal pelvis, stomach, biliary tract and small intestine. Symptoms and signs Symptoms are similar to the CRC in other forms, the diagnosis and treatment of the tumor are the same. The specific diagnosis of HNPCC is confirmed by genetic testing. However, it is difficult to decide who should receive this test because (in contrast to FAP), there is no typical clinical picture. Therefore, the diagnosis requires HNPCC collecting a detailed family history, this should be done at all recent colon cancer patients. Diagnosis Clinical criteria followed by tests for microsatellite instability (MSI) to perform genetic tests to confirm Around the Amsterdam II criteria for HNPCC, all three of the following case history elements must be present: three or more relatives with CRC or HNPCC-associated cancer CRC including at least two generations, at least one case of CRC before age 50 patients who meet these criteria should pay tumor tissue to MSI, a DNA abnormality that can be tested; However, most commercial and hospital pathology laboratories now make this test in all colorectal Adenokarzinomproben. In the presence of MSI genetic testing for specific HNPCC mutations is indicated. Other professionals use other criteria (eg. B. Bethesda criteria) to initiate an MSI testing. If an MSI testing on site is not available, the patient should be referred to an appropriate center. Patients with a confirmed HNPCC require continued inspections because of the occurrence of other cancers. As early detection measures, an annual endometrial aspiration or transvaginal sonography are recommended for endometrial cancer. For ovarian cancer, the options are an annual transvaginal sonography and determining the CA-125 levels. Another option is a prophylactic hysterectomy and oophorectomy. Urinalysis can be used to search for renal tumors. First-degree relatives of patients with HNPCC should receive from the age of 20 every 1-2 years, a colonoscopy after age 40 year. first-degree female relatives should be tested annually for endometrial and ovarian cancers. More distant relatives should get a genetic test; if the result is negative, they should get colonoscopies at recommended for patients at average risk intervals. Therapy Surgical resection Treatment usually consists of resection of Indexläsion with regular search for other colon diseases and associated tumors in other organs. Since most HNPCC tumors proximal to the splenic flexure occur subtotal colectomy was proposed as an alternative, the rectosigmoid remains intact. In any case, be closely follow-up is necessary. Summary Certain autosomal dominant mutations carry a lifetime risk of 70-80% for the development of colorectal cancer (CRC). The patients also have an increased risk for other cancers, particularly of the endometrium and ovaries. The symptoms, initial diagnosis and treatment are similar to those of other forms of CRC. Patients with certain familial risk factors should have their tumor tissue microsatellite instability (MSI), have a DNA abnormality, investigate; If MSI is present, genetic tests are performed. In first-degree relatives should be performed a colonoscopy every year from the age of 20 every 1-2 years and after age 40; Women should be tested annually in addition to endometrial and ovarian cancer. In distant relatives genetic testing should be performed.

Health Life Media Team

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