Hello

I want to watch a Korean drama where the lead character has some sort of a disease / illness/ cancer

PLEASE REFER TO MY LIST BEFORE RECOMMENDING ANYTHING !!

http://mydramalist.com/dramalist/Peach

Thanks a lot
You should try " I'm Sorry, i love you "
i second "i'm sorry, i love you " also u can try " 1 litre of tears "
What else , I want more options "_"
I usually avoid drama like that like a plague but I guess the best I can give you is Autumn concerto.....he had brain tumor I think....
Padam Padam, but really this is a staple in MOST dramas so you should have a field day trying to find what you're looking for. I personally hate seriously/terminally ill characters in my entertainment, esp when it's the lead! ::shudder::...
stairway to heaven smile again foolish mom padam padam Robber sad love song sang doo, let's go to school the snow queen tree of heaven
Scent of a woman - cancer Snow queen - heart problem 90 days of love - warning its biological cousins in love Autumn tale A thousand day promise Greatest love My friend is still alive - one episode drama special
Foolish Mom - Perfect mixture of all genres except action and very unpopular.
The Snow Queen
Ruler of Your Own World- He has a brain tumor.
Flowers For My Life- He's terminally ill.
If In Love Like Them- Both leads are sick. One has cancer while the other has leukemia, as it says in the synopsis.
Can You Hear my Heart Wonderful life Innocent man Good Doctor Autumn's concerto The best is Autumn's concerto.:)
Thanks to you all ^_^
You should check out A Thousand Day's Promise. Uh it is so good that I even cried a bit, so if you want one  an I'll character than I seriously recommend that one. Hope you enjoy it ????
mental illness in Mask , Hyde Jekyll Me and Kill Me Heal me 
I recommend Falling for Innocence, it's an amazing drama! Male lead has dilated cardiomyopathy.