___________________________________________________________________________ Colorectal Cancer
• Polyp surgery • Diagnoses: -
A family history of colon or endometrial cancer diagnosed before 50 years of age is another red flag. Early age at diagnosis of cancer in a closely related family member suggests that genetic factors are playing a role in the development of disease, and these factors can be passed on to other relatives. If multiple family members have been diagnosed with colorectal cancer, or other Lynch/hereditary nonpolyposis colorectal cancer (HNPCC)-related cancers, this strongly suggests genetic factors are increasing individual cancer risks, especially among first- degree relatives [87; 88]. One to two polyps in a lifetime is common, but more than 10 in a lifetime is unusual and suggests genetic contribution. Polyposis is associated with increased colorectal cancer risk. In addition, diagnosis of two or more Lynch/HNPCC-associated cancers suggests an inherited mutation, increasing the overall risk for cancer in different organs. Past diagnosis of Lynch/HNPCC, FAP, or other inherited cancer syndrome in a family member is another risk factor. Many of these conditions are inherited in a dominant pattern, but not everyone who inherits gene mutations for these conditions develops cancer. Therefore, a diagnosis of HNPCC in a grandparent may be relevant to the patient. Patient Colorectal Cancer Risk Level Of total colorectal cancer cases, 75% are due to sporadic disease without apparent inherited origin, 10% to 30% are due to familial risk factors, and 5% to 6% are due to heritable genetic mutations.
Colorectal cancer (and age at diagnosis)
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Polyposis syndrome
Extracolonic conditions such as osteoma, sebaceous cysts, desmoid tumors, congenital hypertrophy of retinal pigment epithelium (CHRPE), or extra teeth
• Genetic testing for polyposis or hereditary cancer • Is relative willing to sign release to share relevant medical records? In addition to familial factors, patients’ personal risk factors should also be assessed ( Table 1 ). Patients should be assessed for all cancer types. Cancer syndromes include risk for multiple types of malignancy; colorectal cancer is not always a presenting cancer. A three- generation pedigree is the gold standard. The minimum for colorectal cancer should include cancer and polyp history for the patient’s generation and two previous generations. The patient’s risk status can change over time with updated personal or family history. Assessment Red Flags Findings suggestive of heritable colorectal cancer risk are termed “red flags” and direct the healthcare provider to probe further. One red flag is a personal history of colon cancer diagnosed before 60 years of age or endometrial cancer diagnosed before 50 years of age [87; 88]. Early age at diagnosis suggests that genetic factors are playing a strong role in the development of disease.
PERSONAL COLORECTAL CANCER RISK FACTORS
Age Older than 50 years Medical conditions Inflammatory bowel disease History of ≥1 adenomatous polyps (size ≥1 cm, with high-grade dysplasia or villous features that confer higher risk) Cancer history Personal history of colorectal cancer Personal history of other Lynch syndrome/hereditary nonpolyposis colorectal cancer (HNPCC)-associated cancers, including endometrial, ovarian, small bowel, gastric, ureteral/renal pelvis, hepatobiliary/pancreas, brain (particularly glioblastoma), or sebaceous adenoma/cancer Early-onset colorectal cancer or Lynch syndrome-associated cancer Genetic factors Confirmed carrier of a mutation that causes a hereditary colorectal cancer syndrome Lifestyle, behavioral, and dietary risk factors Diet high in saturated fats and red and processed meats
Diet low in folate Physical inactivity Obesity Smoking ≥2 alcoholic drinks/day Source: [87; 88]
Table 1
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MDFL2626
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