Too much sugar is not good for your metabolism; it can lead to diabetes and heart issues.
As far as cancer is concerned, most evidence is anecdotal, not hard science.
Cancer cells have the ability to consume sugar, proteins, fats, carbs, ketones, glutamine - in fact, most waste products in your body…EVERYTHING you see on the internet that some crackpot guru tells you “feeds” cancer.
@kjacko’s remark about whole fruits vs juices is an excellent one, and it has more to do with glycemic load (your body’s rapid production of insulin in response to a lot of sugar). Juices are pure sugar water, whereas whole fruits contain fiber and pectin which slow down the absorption of sugar, and thereby the production of too much insulin.
However, prolonged glycemic load over months and years could lead to “hyperinsulinemia” - or simply the production of too much insulin and THAT has been implicated in cancer growth and progression (and diabetes).
But that process is extremely complex and eliminating all sugar from your diet is NOT going to prevent cancer.
But this is just my opinion and you really have to do your own research, using sources such as the NIH, JAMA, or university research papers. Reading books by Dr Gundy and Dr Mercola is a waste of your time and energy. Best
Phil