Spacing out maintenance chemo

Sorry no one has had an answer for you. My experience may be a bit different but my regular chemo was postponed by two weeks once. It doesn't seem to have made much difference.

This is an interesting prior discussion on Mayo Clinic Connect.

Your question doesn’t have an easy answer! Much depends on your individual circumstances - including your type of cancer, how aggressive it is, how your body handles the schedule etc.
https://connect.mayoclinic.org/discussion/maintenance-chemo-every-3-weeks-for-2-years/

Yes. But not on a regular basis. I'm on Enhertu for endometrial cancer. I've been on it for 20 cycles (every 3 weeks for over a year now). I had one 6-week reprieve in 2025. Nothing disastrous happened. I will have another reprieve this May, and expect that no detrimental effects will occur.

Dear @mil63 Yes. Twice. I was not on what you would consider maintenance yet, but had a complete response after four of six treatment cycles. The complete response after 4 treatment cycles was determined by very precise CTDNA testing and scans for my bladder cancer. The first time I went on a four week hiatus because of multiple blood clots in my arms from the infusion ivs. I should note that I have a highly aggressive form of advanced muscle, invasive bladder cancer that has a high probability of returning even with treatment. The second more recent time I went on a two month hiatus after six cycles because of multiple debilitating side effects from different treatment. The original plan for these 2 new drugs (padcev and Keytruda) was to stay on them until they stopped working or until my body couldn’t tolerate it anymore. I resumed treatment with Keytruda and based on recent testing my cancer is still non-detectable. I feel my awesome medical oncologist made the best decision both times due to precision testing and because of what the side effects were doing to me. I wish you the best!