Malignant tumors associated with juvenile polyposis syndrome in Japan.

PURPOSE: The risk of malignant tumors developing in association with juvenile polyposis syndrome (JPS) was evaluated to explore the optimal treatment for this rare disease.

METHODS: We reviewed the data on JPS cases reported in Japan between January, 1971 and March, 2016.

RESULTS: A total of 171 cases were evaluable. Of these 171 patients, 83 (48.5%) were female and the median age at diagnosis was 28 years (range 1-80 years). The polyps were located in the stomach alone (n = 62; 36.3%), in the stomach and intestine (n = 47; 27.4%), or in the colorectum alone (n = 62; 36.3%). The sites of malignant tumors were the stomach (n = 31), colorectum (n = 29), small intestine (n = 2), breast (n = 1), and thyroid (n = 1). The lifetime risk (at 70 years) of any malignant tumor was 86.2%. The lifetime risk of gastric cancer was 73.0% and that of colorectal cancer was 51.1%. The risk of these cancers developing was dependent on the type of polyp distribution.

CONCLUSIONS: Long-term surveillance of the stomach and colorectum based on the phenotype of JPS seems a reasonable approach to monitor these patients for the development of malignant tumors.