SPOILER ALERT! well not really but I had to type atleast 100 letters ;p

Anyway those two dramas are quite simmillar Fantasy/romance drama with a weird twist.

"I Want to Eat Your Pancreas" is like poor man's "1 Litre no Namida" ;] ... but still worth watching.

"Tomorrow..." is more of romantic/fantasy drama than real life story like "1 litre.." but somehow I found them very simmilar..
They both makes you rethink your actions and priorites in life.
Life that can be very short, fragile and unjustice.