About Hereditary Nonpolyposis Colorectal Cancer Syndrome

Overview

Hereditary nonpolyposis colorectal cancer (HNPCC) Syndrome, also known as Lynch syndrome, is a genetic condition passed down through families that increases the chance of developing certain types of cancer. People with HNPCC are more likely to get colon cancer, especially in the upper part of the colon. They are also at a higher risk of developing other types of cancer, such as stomach, endometrial (cancer in the lining of the uterus), pancreatic (cancer in the pancreas, an organ that helps digest food),bile duct cancer (cancer in the tubes that carry bile from the liver to the small intestine). They can also develop cancers in the blood (cancers that affect how blood cells grow and work). Women with HNPCC are at a higher risk of developing endometrial cancer and ovarian cancer.

HNPCC happens because of problems in certain genes that are supposed to fix mistakes in DNA when cells divide. When these genes don’t work properly, errors can build up, leading to cancer. People with HNPCC often get cancer earlier in life, and it’s common to see it run in families. Early testing and medical care are very important to help find and prevent cancer in people with this condition.

Causes and Risk Factors

The cause of HNPCC:

• Genetic changes (mutations): HNPCC is a genetic condition that is passed down in families. It happens because of changes (mutations) in certain genes, such as MLH1 and MSH2, which are important for fixing mistakes in DNA. If a parent carries this changed gene, they can pass it to their children.

The non-modifiable risk factor for HNPCC cannot be changed or controlled. This includes:

• Family history: Having a first-degree relative (parent, sibling, or child) with HNPCC increases the risk of developing the syndrome.
• Increasing age: The risk of developing HNPCC-related cancers increases with age.
• Previous history of polyps: People with a history of polyps have a higher risk of developing colorectal cancer.

The modifiable risk factors for HNPCC are similar to those for colorectal cancer in general. These are factors that can be influenced or changed and include:

• Unhealthy eating: Eating a diet high in processed meats, red meats, and low in fruits and vegetables, may increase the risk of developing colorectal cancer.
• Physical inactivity: Not getting regular physical exercise has been linked with an increased risk of colorectal cancer.
• Obesity: Being overweight or obese is a risk factor for colorectal cancer.
• Cigarette smoking: Smoking tobacco has been linked to an increased risk of developing colorectal cancer.
• Heavy alcohol use: Drinking too much alcohol has been linked with an increased risk of colorectal cancer.
• Urban residence: Living in cities may increase the risk of colorectal cancer due to factors such as pollution and lifestyle differences.

It is important to note that these modifiable risk factors are not specific to HNPCC but apply to colorectal cancer in general. It's always best to talk with your healthcare professional for personalized advice and guidance on managing your specific risk factors.

Symptoms

Most people with HNPCC won’t notice any symptoms until they develop colorectal cancer. When cancer begins to form in the colon, some common symptoms might include:

• Rectal bleeding
• Changes in bowel habits, like constant diarrhea or constipation that lasts for more than a few days
• Narrow (thinner) stool
• Abdominal pain

As HNPCC progresses or becomes more severe, some people may experience symptoms that last longer, including cramps, pain, or aches in the abdomen and pelvic areas.

• Other symptoms that may be linked with later stages or progression of HNPCC syndrome include: anemia (a condition where the body doesn’t have enough red blood cells, causing fatigue or weakness)
• Unintentional weight loss
• Fatigue and weakness,
• Nausea and vomiting,
• A feeling that the bowel is not fully empty, even after a bowel movement.

It is important to note that these symptoms can also be caused by other conditions, so it is important to talk with a healthcare professional for the right diagnosis and treatment.

Diagnosis

To diagnose hereditary nonpolyposis colorectal cancer syndrome (HNPCC), the following exams, tests, and procedures are commonly performed:

• History and physical exam: A healthcare provider will ask you about any symptoms or factors that might be causing your condition. They will look for physical signs of a medical problem, such as abdominal tenderness or pain, swelling or bloating in the abdomen, or signs of rectal bleeding or changes in stool appearance.
• Lab tests: Blood tests or other samples may be taken to check for genetic changes or markers linked to HNPCC, such as changes in MMR genes. Stool testing for blood might also be done.
• Imaging studies: CT (computed tomography) scans or MRIs (magnetic resonance imaging), or other imaging may be used to see the colon and other organs to look for unusual changes.
• Clinical procedures: These may include biopsies, where a small tissue sample is taken to look for cancer cells or other problems under a microscope.

To determine the stage or severity of HNPCC, additional exams, tests, and procedures may be recommended:

• Genetic testing: This can find specific gene mutations linked with HNPCC and help check the risk of developing colorectal cancer.
• Colonoscopy: A thin, flexible tube with a camera is inserted into the rectum to look inside the colon and check for polyps or other problems.
• Endoscopy: This procedure involves using a thin, flexible tube with a camera to examine the upper digestive tract including the stomach and part of the small intestine.
• Imaging studies: Additional imaging techniques like PET (positron emission tomography) scans may be used to look for signs of cancer.

Remember, these recommendations may be different depending on your situation. It's important to talk with a healthcare professional for personalized advice.

Treatment Options

While there is no direct treatment for HNPCC itself, the goals are to improve health outcomes and reduce the chances of serious illness or death by watching and controlling cancer risks related to the condition. Here are some recommended treatments and how they work towards achieving these goals:

Medication types:

• Chemotherapy: This treatment uses drugs to kill cancer cells or slow their growth.
• Targeted therapy: A treatment that uses drugs to target specific parts of cancer cells, stopping them from growing.

Therapies:

• Immunotherapy: This treatment helps the immune system recognize and attack cancer cells.
• Radiation therapy: High-energy beams are used to destroy cancer cells or shrink tumors.

Therapeutic procedures:

• Surgery: It involves removing cancerous tumors or affected organs to prevent the spread of cancer.
• Colectomy: Surgical removal of part or all of the colon may be needed in some cases.

Health behavior changes:

• Regular screening: People with HNPCC should have regular colonoscopies for early detection and removal of precancerous polyps.
• Healthy lifestyle: Keeping a healthy weight, exercising regularly, and avoiding tobacco and drinking too much alcohol can help reduce the risk of cancer.

It's important to note that the specific treatment will depend on personal factors like how advanced the cancer is, overall health, and the unique traits in your DNA that can affect how the cancer grows or how your body responds to treatment. Talking with a healthcare professional is important to find the best treatment for you.

Medication dosing may be affected by many factors. Check with your health care professional about dosing for your individual situation. Other side effects can occur. Check with your health care professional or read the information provided with your medication for additional side effect information.