Colorectal Cancer in Cowden Syndrome

Patients with Cowden syndrome (CS) are at high risk for early-onset colorectal cancer, according to the December issue of Gastroenterology.

CS is caused by mutations in the tumor suppressor gene phosphatase and tensin homolog (PTEN). Patients typically have mucocutaneous lesions, large-sized heads, and increased risk for breast, thyroid, and endometrial cancers. Although the gastrointestinal (GI) tract is also affected, there have not been large, systematic studies of GI cancers in people with CS. Brandie Heald et al. investigated GI cancers and other lesions in 127 patients with PTEN mutations associated with CS.

Of the patients that received colonoscopies, 93% had colorectal polyps—half of these were hyperplastic and most patients had 2 or more histologic types. Surprisingly, 13% of these patients were found to have colorectal cancer—all were younger than 50 years old. The patients also had innumerable polyps in the ileum, duodenum, stomach, and/or esophagus; one patient had gastric cancer.

Heald et al. calculated that CS increases the risk for colorectal cancer by more than 200-fold. The authors concluded that PTEN-associated CS should be considered a mixed polyp syndrome, and that patients with PTEN-associated CS should receive yearly colonoscopies— especially those found to have hyperplastic or adenomatous polyps. Almost 20% of PTEN mutation carriers with colorectal adenomatous polyps developed colorectal adenocarcinomas.

About 75% of patients also had macrocephaly, so a combination of head size (more than 58 centimeters in men and 57 centimeters in women) and presence nonadenomatous polyps might be used to identify patients with CS.

More Information on CS and PTEN:

Read the article online:
Heald B, Mester J, Rybicki L, et al. Frequent gastrointestinal polyps and colorectal adenocarcinomas in a prospective series of PTEN mutation carriers. Gastroenterology 2010;139:1927–1933.

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