Hrithik made the revelation on Instagram.
"Asked my dad for a picture this morning. Knew he wouldnt miss gym on surgery day. He is probably the strongest man I know.
"Got diagnosed with early stage squamous cell carcinoma of the throat a few weeks ago, but he is in full spirits today as he proceeds to battle it. As a family we are fortunate and blessed to have a leader like him," the actor wrote with a picture of his father standing side-by-side him in a gym.
Replying to PM Modi's tweet, Hrithik said the surgery of his 69-year-old father went well.
"Thank you Sir for your concern and good wishes. I am very happy to inform that according to the doctors his surgery has gone off well," Hrithik said.
The father-son duo has worked together in Hrithik's launch vehicle "Kaho Naa... Pyaar Hai", "Koi... Mil Gaya", "Krrish" series and "Kaabil".
Roshan's daughter Sunanina was diagnosed with cervical cancer a few years ago but emerged a survivor.
Roshan started out as an actor with films such as "Kaamchor" and "Khoobsurat", among others but later turned to filmmaking and sporadic guest appearances.
Some of his notable directorial works include "Khudgarz", "Khoon Bhari Maang", "KaraROSHAN-CANCERn Arjun" and "Koyla".
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)