What to do after your colon cancer has been resected was thought to be established: have a colonoscopy at one year, then every three to five years thereafter unless something like an adenoma (premalignant polyp) is found. Also, get a CEA blood test every three to six months for five years, less often thereafter. Maybe get a CT scan annually. Now two large, well done and important studies have blown up this concept. Colonoscopy is still OK but there you are looking for the next cancer, not the one removed. In the Journal of the American Medical Association Dr. Primrose and colleagues from the UK looked at whether intense followup scrutiny consisting of both CT scans and frequent CEA made a difference. The link above will take you to the table of contents of that issue. The article is free. More patients in the intense followup group had second look surgery to attempt to remove metastases, found by CEA elevations, CT or both, but these operations failed to cure so often that they were in general a waste of time and effort. Recently a group from Memorial Sloan Kettering Cancer Center in New York published a study in the Journal of the National Comprehensive Cancer Network looking at all their colorectal cancer patients over a ten-year period whose CEA started to rise. This link will take you to the abstract. Dr. Stark can email you the entire article if you fill out the form to the right. Half of all rising CEA’s signified nothing, i.e., no evidence of cancer could be found on thorough investigation and with ample followup to be sure they were not missing anything. One third of all the false-positive elevations were a single event with the CEA returning to normal but two thirds of the time the CEA stayed up. Still…no cancer. One tenth of the elevations signified a new cancer unrelated to colon cancer (e.g., breast, lung, bladder, prostate), for an overall pickup rate of 5% in patients with resected colon cancer. The authors did not think that a 5% yield justified CEA just for that. So, should doctors bother getting CEA’s any more in this group of patients? Dr. Stark weighs in, “In thirty-four years of Oncology practice I never saved a life with all the CEA’s I obtained in this setting. However, since both my national society ASCO and the National Comprehensive Cancer Network strongly recommended this practice, I felt that to ignore it would leave me open for a lawsuit if a patient recurred and I was slow to pick it up. The big picture is that there is no strategic advantage to the early diagnosis of metastatic disease. I am happy that this issue is getting another airing. Perhaps ASCO and NCCN will adjust their guidelines since these two important papers were just published.”
Update 2020: this paper, originally published in 2014, has not been improved upon. The NCCN still recommends CEA screening. However, a recent publication suggests that circulating tumor-associated DNA mutations will likely replace CEA as a way to follow these patients once the technology is perfected and the cost comes down.