86 yr male with pT3N1b moderately diff sigmoid colon adenoca. PS 0. MLH1 and PMS2 deficient. He has positive family history so testing for Lynch with germline testing. Should that result impact his therapy or since his tumor is dMMR offer xeloda +/- oxaliplatin? Have you used half dose oxali per FOCUS2 data? Should I just stick to Xeloda at this age? I have not had good outcomes with oxali in patients over 80y. I know we go by ECOG but can you share the oldest patient that you have had tolerate this approach of easing in Oxali? I'm just a bit weary after my last 78y ended up in ICU then rehab for months after adjuvant FOLFOX.
This is a great question. To me it’s either between observation and 3 months of DR CAPOX. Single agent 5fu/cap hasn't shown to have survival benefit in MSI-H stage III compared to surgery alone but adding oxali has shown a significant benefit, so you need both and would prefer 3 CAPOX over 6 mo FOLFOX. FOCUS2, I think, started patients at 80% DR but had a well-detailed out dose reduction plan that's in its published methods. I would start there (or even 60% for the oxali to ensure tolerance). ECOG 0 is encouraging, so hopefully with enough symptom-targeted treatment, he’ll do OK. If he can’t tolerate, at worst you watch him close and have IO in back pocket if/when needed down the line.
I've had a few in their 70s and it's 50/50 who are able to complete. Always require dose-reduction(s). I think you can justify surveillance just as well in this situation. Think it comes down to how robust the patient is and how motivated they are to try chemo/how OK they are with just observation. If they want to try would do 60-80% cap and 60% oxali cycle one and see them back in the clinic (or via telemed) half way through the first cycle to keep a close eye. If you don't have a good feeling about it, and they are ambivalent, go with surveillance and do scans q3 months for the 1 yr rather than q6 mo.
