DNA signature and occult blood in stool led to diagnosis of an early-onset metastatic rectal cancer in a young pregnant woman: a case report

Background: Colorectal cancer (CRC) is the third most common form of cancer worldwide in terms of incidence and the second in terms of mortality with 1.9 million new cases and 930,000 deaths reported in 2020. Corresponding numbers in the U.S. are 150,000 and 53,000, respectively. Although the majority of CRCs in the U.S. and other high-income countries are in adults aged 50 and older, there has recently been a considerable rise in early-onset CRC, so that 17,930 cases in the U.S. (12% of total cases) are diagnosed in individuals younger than age 50, representing the equivalent of 49 new cases per day. Early diagnosis is essential to improve the prognosis and reduce the number of cancer-related deaths. Here we report the case of a young pregnant woman, who was diagnosed with CRC with the help of the ColoAlert™ multitargeted stool test. Case Description: In this case study, a young pregnant woman presented with obstipation, rectal bleeding, and pelvic pain, symptoms that were ascribed to her pregnancy. On her own, she performed a multitarget stool test (ColoAlert™) that showed occult blood as well as a very high level of human DNA, both known to be associated with presence of CRC. After testing, she was referred for rectoscopy (during her 21st week of pregnancy), which showed an exophytic, semicircular tumor 10 cm from anus in the rectosigmoid junction. Histology confirmed adenocarcinoma in rectum. Further examination showed perirectal infiltration as well as metastases to both liver and adrenal gland. Conclusions: This case report shows the importance of considering CRC as a possible diagnosis in young people. It also demonstrates the usefulness of multitarget stool testing that in this case led to the endoscopic confirmation of the diagnosis followed by an immediate start of potential life-saving treatment.