* Venezuelan leader had tumor removed in Cuba 3 months ago
* Vows to be fit to run for re-election next year
CARACAS, Sept 17 Venezuela's cancer-stricken leader Hugo Chavez said he will return to Cuba on Saturday for a fourth and probably last round of chemotherapy, vowing to be recovered and fit for a tough re-election campaign next year.
The charismatic leftist has led Latin America's top oil exporting country since 1999 and wants to stay in office until at least 2025 to consolidate his self-styled "revolution."
But his hopes for a lengthy rule were put in doubt by a cancer diagnosis this year.
"I will go to Cuba this afternoon," the 57-year-old Chavez, dressed in an olive green military uniform, said in a speech televised from Caracas. "Early tomorrow I will start the fourth round of chemotherapy, which will most likely be the last."
Chavez, who had the constitution changed to allow perpetual presidential re-elections, said he expected to return to Venezuela by the middle of the week after about five days of treatment.
Chavez plans to run for another six-year term in the October, 2012, election. [ID:nN1E75T2BK]
But in June he underwent surgery in Cuba to remove a tumor in the pelvic area, throwing added uncertainty into Venezuela's upcoming political season. [ID:nS1E78D1RG]
The opposition has accused him of putting Venezuela's national security at risk by spending so much time in Cuba for treatment. But the president said the public understood why he was traveling abroad to seek the best possible care.
Chavez has become Washington's main irritant in Latin America -- a mantle inherited from his mentor, Cuba's Fidel Castro. The fiery Venezuelan leader says he wants to rule for at least two more six-year terms.
The opposition aims to elect a unity candidate in a February primary and go on to unseat Chavez in the Oct. 7, 2012, vote. [ID:nS1E78G039] (Reporting by Deisy Buitrago and Hugh Bronstein; Editing by Vicki Allen)