You'll know if the tumor is shrinking without a test because swallowing gets easier. We did liquid diet for a while, then progressed to soft food and back to well chewed regular food. As we went through radiation it got easier to eat, until the throat got sensitive near the end. I made a fresh organic soup every morning, (didn't want any chemicals or pesticides moving through his esophagus) so I came up with a few interesting soup recipes until we moved back towards regular food, then we went into things like applesauce and mashed potatos. Cream of wheat has been a morning staple in my house ever since (tried cream of rice for variety but he didn't like it). You'll get the hang of it and learn to adjust.