AM/PM glucose differences are probably going to be swamped by mundane stuff like who has a snack before treatment vs. who doesn't. Are you not supposed to eat before immunotherapy? If so, maybe (non)compliance with that requirement is what's underneath.
i'd think the local acidity (build up of lactic acid resulting from glucose over-consumption by the cancer cells) would take a bit to build back up once glucose ups after the night.
