Yes indeed, sugar does feed cancer - virtually every kind of sugar, though none are worse than common refined sugar. And that includes items like bleached white bread which the body easily converts to sugar. No doubt refined sugar and bleached white bread are about as unhealthy of food items as you can find - in fact, the World Health Organization has identified refined sugar as the number one cause of health problems in the world.
As someone who has researched cancer and natural alternativess it is amazing to me to see just how little our system of medical education has done to educate doctors about what causes cancer and helps it grow or what prevents it and helps beat it. Not very long ago, it was not uncommon for oncologist offices to have a bowl of CANDY sitting out in the reception area!
Of course, there is no profit in prescribing healthy diets and lifestyle choices or inexpensive natural supplements and alternative therapies, and do our doctors have not been taught much about them - although there is an ecouraging trend in recent years to better educate our doctors about such things.
For a good look at that we know, or feel pretty sure we know, about cancer, take at look at the article "Modern Medicine versus Nature in Treating Cancer"
http://www.tbyil.com/MMvsNature.htm