You still got it mixed up a bit though. There is no “normal” respiration, cells use both types of respiration all the time.

current estimates [of the yield in aerobic respiration] range around 29 to 30 ATP per glucose. Aerobic metabolism is up to 15 times more efficient than anaerobic metabolism (which yields 2 molecules of ATP per 1 molecule of glucose).

Anoxic regeneration of NAD+ is only an effective means of energy production during short, intense exercise in vertebrates, for a period ranging from 10 seconds to 2 minutes during a maximal effort in humans. (At lower exercise intensities it can sustain muscle activity in diving animals, such as seals, whales and other aquatic vertebrates, for very much longer periods of time.)

Maybe you could link an article or a study where you’ve hear about this cancer connection? Would be curious what’s behind it.