I've posted about alkalizing the body several times. How dangerous it is, and the fallacy of it contributing to cancer cures. Cancer produces acid by its very own lifecycle. Even our friendly bacteria produces acid, and is the reason the intestines are slightly acid and must remain that way. Cancer can thrive in any environment. The body has numerous systems to balance the pH all by itself.
But the real reason why alkaline water is a scam is that it has no buffers to maintain its pH. The instant the alkaline water hits your very acidic stomach, the pH is neutralized as there are no buffers. Truly alkaline water would have an alkaline buffer like baking soda (sodium bicarbonate), which is also our body's natural alkaline buffer.