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treatment only. When we stopped to examine the tumor by flexible sigmoidoscopy and MRI imaging at 12 to 16 weeks after completion of TNT, these patients oftentimes have no tumor left and may be eligible to enter into a“ watch and wait” surveillance strategy. This is also coined as“ organ preservation” and is particularly helpful for very low rectal cancers where an abdominoperineal resection or a low colo-anal anastomosis may be necessary: these are more difficult overall to deal with on a daily basis post-op.
Another new strategy for colon cancer surveillance is the issue of using circulating tumor DNA or CTD DNA instead of Carcinoembryonic antigen testing, or CEA. I feel that mostly the data is mixed from different centers, and this is why it has not made it into the NCCN guidelines just yet. However, the best evidence out there supports the use of deciding which stage 2 patients should get adjuvant chemotherapy. I find that it is more widely used and accepted by oncologists, it has a very high specificity for tumor recurrence and likely helps guide use of PET scan to determine if there is any other detectable disease.
The last major advance that has been made in CRC treatment has been immunotherapy. PD1 / PD-L1 inhibitors block the interactions among tumor cells that help the tumor“ hide from” the immune system. The data are quite convincing for metastatic colon cancer in terms of progression free survival and response rates, and these agents are in the NCCN guidelines for locally unresectable, inoperable or metastatic colon cancer. However, the results for rectal cancer have been so impressive that it is now the first preferred approach for an MMR deficient rectal cancer prior to entering the traditional TNT pathway. We do this at our institution, and so far, I have yet to see a tumor that was still present and required the TNT treatment after receiving immunotherapy. Those patients also entered the“ watch and wait” protocol.
Lastly, I highlight the ever-increasing alarming epidemic of early onset colorectal cancer. This rate increases by 4.4 % per year in the 40 to 50 age group and at 3 % per year in the 30 to 40 age group. This is an area of high priority for the National Cancer Institute and every grant-funding organization trying to get a handle on this epidemic. When we look at worldwide rates, the U. S. and Canada by far and away have higher rates than Europe and Africa.
This article was written by the guest speaker as a summary of her live presentation.
Dr. Kavalukas is a colon and rectal surgeon at UofL Health and an Assistant Professor in the Division of General Surgery at the University of Louisville.
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