Yes and I think that's a myth. Otherwise no diabetic could beat cancer and that's clearly a falsehood. Many have beat cancer.
Actually it is not a myth. As I pointed out earlier though most diabetics keep their diabetes under control by diet, medication, herbs and exercise. If they did not keep the diabetes under control then we would see a lot more cases of diabetic coma than we would see cancer in diabetic patients.
Also keep in mind that inhibiting glucose is only one means of dealing with cancer. Diabetics with cancer can still target other aspects of cancer such as mitosis or angiogenesis inhibition to target their cancers. Therefore, they can still overcome cancer even if the cancer is being fed by excessive glucose.