Article On CRC MSS and Tumor Mutation Burden and response to Immunotherapy

[Jack&KatiesMommy]

Here is a link to a Foundation One Article that is, in part, based upon the results of my case and relates specifically to MSS TMB and Colorectal Cancer's response to immunotherapy:

https://www.foundationmedicine.com/blog ... tal-cancer

[chadwick1]

Thanks for the link, it's really interesting stuff! I'll cross-link to your other thread in case anyone finds this and wants to read more of that discussion.

http://coloncancersupport.colonclub.com/viewtopic.php?f=1&t=60593

[henry123]

That's good news if a new biomarker is found that indicates potentially immunotherapy could work for some CRC patients.

[boswind]

It is new that TMB guides cancer treatment, but it is really exciting. I read the paper that Foundation One’s article has a link to. The paper published on J Gastrointestinal Oncology includes two successful cases.

case 1: a patient with stage 4 rectal cancer, MSS, TMB = 223 mut/Mb, is having partial response to Keytruda. Tumors have shrunk by over 50%.

Case 2: another patient with stage 3 rectal cancer, MSS, TMB=14 mut/Mb, achieved a complete response to nivolumab, having 18 month NED.

If we add Cynthia who also had complete response, we see three good cases, although TMB guiding treatment is so new.

[boswind]

Cynthia and other members,

I contacted Foundation One again. I have to correct the info I posted in another thread. To get their TMB, they require tissue samples; their gene tests based on peripheral blood do not provide TMB.

My Onc. stated: to get new tissue samples i have to have a liver biopsy. I feel it is too much to have a liver biopsy just for a TMB test. Most importantly, I believe the chance that I have a TMB higher than 12 mut/Mb is very small statistically, although I have done two targeted medicines: Avastin and Centuximab. If I had a 30% chance of high TMB, I would be happy to have a liver biopsy.

What do you think? What do other members think?

Thank you,

[boswind]

Their paper published in J Gastrointestinal Oncology states that for 5,702 advanced MSS colorectal cancers, their median TMB is only 3.6 mut/Mb. On the other hand, for those 302 cases with MSI-H, their median TMB is 46.8 mut/Mb.