My experience. Markers are an indicator not results. The only way to determine if you have cancer or not is a PET scan and consequently a biopsy, if PET show cancer.

For three years my monthly 15-3 markers were in the high 20's. Then a jump to 56, 101, 156 and 190. In retrospect the wait between 56 and 101 was unnecessary. I would have started my treatment a month earlier.