Shelby's story is too funny!
Also funny how far we'll go to make sure our babies are taken care of - lol - a line on the floor. Kinda makes me wonder how on earth her pawrent figured that out. Did they try a triangle? Or a circle? Hehe, I only laugh because aside every single bowl on premises and our regular plates (all colors-lol) I even tried paper plates for Toby's food - he hates them all. Just why?! Maybe he'll tell me sometime...

Now... a bit of a different issue. Stinky stuff! My goodness his farts are radioactive! I'm not sure if it's the meds or all the human food he's ate... effects are toxic to all surrounding life! He is a pittie, and he was always - errr - gifted in this area, but this here is beyond anything I've ever smelled... horrid!
I think part of the problem might be the Pred making him a bit constipated - raises new question - do you know of anything I could give him to loosen it up a little? He refuses milk and yogurt... I don't mean another drug, just maybe something you know of I could try to get him to eat? I know blueberries are good for diarrea, but what works the other way and is safe for dogs?

Isn't it ironic how after fighting to put some food in him now I'm worried about how to get it out? 

Ahh bummer. Thought I had pumpkin, but it turned out to be canned sweet potatoes. I'll get some next time, he usually likes veggies so who knows...gotta go...his gas makes my eyes water 

Thanks for your suggestions Jerry. 
The fumes are the burgers coming back to guilt-trip me!
Still no poop.
Toby's such a picky eater now... I'm starting to think he somehow associated eating with not feeling good, which would make sense if his tummy hurts from Pred. I'm giving him fish oil gel tabs, which he seems to treat as treats (!) and he licked some coconut oil of my hand... still can't get him to eat from any dish, hehe, even a clear take out container lid is a no-no, so feeding anything sloppy is a challenge. Today Toby likes hot dogs... funny how things change daily.

Ah yes. Thanks for asking
A bit busy these last few days... good news is something worked and he managed to squeeze one Tuesday night. Hard to call it a poop, since something microscopic came out, but better that than nothing. He didn't show any discomfort so I didn't call vet, but fed him right foods for the job all day and he produced another micro one yesterday, followed by almost a normal one in the evening.
Happy dance indeed! He's eating and he's pooping!

I think what worked for him were combination of things, but if I had to call it I'd say it was adding oils/fats and veggies to his food. After additional medicine was added and he started eating again (those first few days on Prednisone were a nightmare) I fed him soft cooked carrots and canned fish  - I'd mush it all up with a fork and used fish/carrot broth to soften some oatmeal and mix it with it. Took almost three days to get him going, but he's actually more regular now then he was before all this started.
He eats this mixture daily now, but he's very picky about what's added to his food, so I have to be careful - so far lots of tuna and mackerel, cooked chicken or beef with brown rice and veggies and such are a go, so that's what I feed him. And hot dogs. Lots of hot dogs - specially when he doesn't want to eat anything else, dogs always work.
He still absolutely refuses any kind of dog food, dry or canned, kinda makes you wonder...

Thank you all for great advice, it would have taken me much longer (if ever) to figure it out without you guys. 

More weird Toby news.
I've found a dish he doesn't mind eating from. It's a huge ceramic plate, but he eats off it only in the living room by the coffee table. He also likes the cat to be jealous of me cooking for him. With fish at that!
Toby was always a bit eccentric, but lately he's putting a new twist on everything. Funny, funny dog.

Very busy work week for me with holidays and all (I work at a skiing resort) - I just wanted to stop by to say hi and leave a quick update.
Toby is doing good - eating and pooping remains regular. At this point I'm absolutely sure it was the drugs messing up his belly, not actual cancer preventing him from eating. I slowly introduced new, healthier foods to him, and we're almost completely off junk food now, lol, no more burgers and hot dogs (finally).
He's gained some weight back, his ribs are not protruding anymore, and his energy levels are sky high - makes me feel very very guilty working all these long hours knowing I should spend more time with him, especially now, when we need to live every day to the fullest... too bad you can't take sick days off from work for a canine child. 
Sadly, there is a dark side to this story too - his lymph nodes are slightly larger again... not much, but enough for me to know... unfortunately I gotta run to work again (sigh). More to come soon!