KLK3 and malignant colon neoplasm: In 2017, the colon cancer follow-up guideline was revised (ie, ultrasounds are no longer needed), which would make it easier to implement colon cancer follow-up as well.25 Despite this revision of the guideline, GPs are still more familiar with providing PSA versus CEA monitoring, since PSA is also used for opportunistic prostate cancer screening.26 The GPs' familiarity with PSA monitoring corresponds with the fact that prostate cancer survivorship care was less often perceived as different from usual care (55% v 74%).