2.8. Sample Size
CRC
When analyzing raw data from a cohort of 257 CRC patients at the Jikei University School of Medicine, the 5-year RFS of the highest quartile of 25(OH)D was found to be 13% higher than that of the lowest quartile [Given an expected annual enrollment of 80 patients, the accrual period was projected to be 5 years to achieve the enrollment of 400 participants. With final patient follow-up conducted 2 years later, the total duration of the planned trial was 7 years.