Interval colon cancer in a Lynch syndrome patient under annual colonoscopic surveillance: a case for advanced imaging...

Lynch syndrome confers increased risk for various malignancies, including colorectal cancer. Colonoscopic surveillance programs have led to reduced incidence of colorectal cancer and reduced mortality from colorectal cancer. Colonoscopy every 1-2 years beginning at age 20-25, or 10 years earlier than the first diagnosis of colorectal cancer in a family, with annual colonoscopy after age 40, is the recommended management for mutation carriers. Screening programs have reduced colon cancer mortality, but interval cancers may occur.

We describe a 48-year-old woman with Lynch syndrome who was found to have an adenoma with invasive colorectal cancer within one year after a normal colonoscopy.

Our patient illustrates two current concepts about Lynch syndrome: 1) adenomas are the cancer precursor and 2) such adenomas may be "aggressive," in the sense that the adenoma progresses more readily and more rapidly to carcinoma in this setting compared to usual colorectal adenomas. Our patient's resected tumor invaded only into submucosa and all lymph nodes were negative; in that sense, she represents a success for annual colonoscopic surveillance. Still, this case does raise the question of whether advanced imaging techniques are advisable for surveillance colonoscopy in these high-risk patients.