Okinawa Gov. Takeshi Onaga was discharged from hospital on Tuesday after undergoing surgery to remove a tumor in his pancreas.
The 67-year-old governor said at a press conference that the removed tumor was malignant and he will continue treatment to prevent metastatic recurrence.
"I would like to return to official duties as soon as possible and fulfill my responsibilities," Onaga said.
He did not clarify whether he would run for another term, as his current four-year term is set to expire in December.
Onaga has been a fierce opponent of the state's controversial plan to relocate U.S. Marine Corps Air Station Futenma from the densely populated residential area of Ginowan to the coastal area of Nago, saying the base should be moved out of the prefecture.
Onaga underwent the surgery on April 21.