Hyperbaric oxygen therapy can induce tumor cell apoptosis and necrosis by reversing hypoxia and causing oxidative stress.

“basically you're hyper oxygenating a whole bunch of damaged mitochondria and essentially what that does is skyrockets superoxide anion which then through Fenton chemistry so when you have a lot of free iron and all you got a whole bunch of heme and stuff that's being broken down the tumor so you have a lot of free iron driving the Fenton reaction and which is producing hydroxyl radicals and that causes a massive oxidative stress specifically to the tumor and you're delivering a massive oxidative stress to the tumor while it's relatively non-toxic to healthy cells”