What are the treatment guidelines for Hereditary Nonpolyposis Colorectal Cancer (HNPCC) or Lynch Syndrome?

Treatment Guidelines for Lynch Syndrome (HNPCC)

For individuals with Lynch syndrome, colonoscopic surveillance should be performed every 1-2 years starting at age 20-25 years (or 10 years younger than the youngest diagnosis in the family) to reduce colorectal cancer incidence and mortality. 1

Colorectal Cancer Surveillance

• Colonoscopy should be performed every 1-2 years starting at age 20-25 years for MLH1 and MSH2 mutation carriers and age 35 years for MSH6 and PMS2 mutation carriers 1
• No upper age limit has been established for surveillance colonoscopy 1
• After age 40, some experts recommend increasing frequency to annual colonoscopy due to accelerated carcinogenesis 1, 2
• Surveillance colonoscopy should be performed by endoscopists experienced with Lynch syndrome, with meticulous attention to the right colon and flat lesions 2

Surgical Management for Colorectal Cancer

• For patients diagnosed with colorectal cancer, subtotal colectomy rather than segmental resection should be considered due to the high risk of metachronous tumors 1, 3
• The decision regarding surgical approach (total colectomy with ileorectal anastomosis vs. segmental resection) should consider patient age, cancer stage, and patient preferences 3
• Following surgery, surveillance of remaining colorectal tissue should continue at the same intervals 1, 3

Extracolonic Cancer Surveillance

Endometrial and Ovarian Cancer (for women)

• Annual gynecological examination, transvaginal ultrasound, and endometrial sampling starting at age 30-35 years 1
• Consider prophylactic hysterectomy and salpingo-oophorectomy when childbearing is completed 1

Gastric Cancer

• Testing for Helicobacter pylori and eradication if positive is recommended for all mutation carriers 1
• In populations with high incidence of gastric cancer, consider upper GI endoscopy every 1-3 years 1

Urinary Tract Cancer

• Annual urinalysis with cytology beginning at age 30-35 years 1
• Evidence for this recommendation is based on expert consensus (low quality evidence) 1

Special Considerations

• Quality of colonoscopy is crucial - adequate bowel preparation, sufficient withdrawal time, and complete polyp removal are essential to prevent interval cancers 2
• Adenomas in Lynch syndrome may progress to carcinoma more rapidly than in sporadic cases, with progression possibly occurring in less than 3 years 1, 2
• Lynch syndrome-associated colorectal tumors are more commonly located in the right colon and may present as flat or lateral growing polyps, requiring heightened vigilance during endoscopy 2
• Aspirin has shown promise as a chemopreventive agent and should be considered in patients without contraindications 3

Genetic Testing and Risk Assessment

• Tumor MMR (mismatch repair) testing should be performed on colorectal cancer tissue from affected family members to assist in diagnosis 1
• Families meeting Amsterdam criteria where MMR testing is not possible should be offered surveillance as per Lynch syndrome guidelines 1
• Regular education, genetic counseling, and review of family history should be provided to all individuals with Lynch syndrome starting at age 21 1

By following these comprehensive surveillance and management guidelines, the morbidity and mortality associated with Lynch syndrome can be significantly reduced through early detection and appropriate intervention.