Crowe said he believed worrying about cricket, particularly the axing of his protege Ross Taylor as New Zealand captain late last year, exacerbated his lymphatic cancer, leading to a large tumour in his stomach.
After five months of chemotherapy, the 50-year-old said doctors had told him his cancer had shrunk to safe levels, although there was always the possibility of a relapse.
"All through my left side the lymph nodes have gone back to their normal size," he told RadioSport.
Crowe said the impact that the controversial decision to drop Taylor in favour of Brendon McCullum had on his health showed him he needed to step away from the game.
"(It fuelled) my anger, my negative emotion, my response to a fight that wasn't even mine," he said.
"It just conjured up 20 years of suppressed anger towards this organisation (New Zealand Cricket) that I had devoted a lot of my life to. I literally couldn't stomach what was happening to Ross.