Chavez back in Venezuela after radiation therapy CARACAS (Reuters) - President Hugo Chavez returned home to Venezuela on Thursday after a first session of radiation treatment in Cuba that he hopes will cure his cancer and allow him to win a new six-year term in October. The 57-year-old socialist leader has said he will be flying back and forth between Caracas and Havana over the coming weeks as he undergoes therapy, removing himself from the political stage just as his election rival gears up his campaign. Very little is known about Chavez's condition - he has had three cancer operations in less than a year - so doubts remain about the future of the man who had dominated politics in South America's biggest oil exporter for the last 13 years. It's a hard battle ... I'm good and will continue to be good. I've taken the treatment very well, thanks to God" he said, flanked by ministers during an hour-long pre-dawn speech broadcast on state TV from the Miraflores presidential palace. The opposition has insisted the president appoint a temporary leader to run the government during his absences in Cuba, something that Chavez has repeatedly rejected. "I may have reduced my speed, but the government has accelerated ... there is no power vacuum," he said on Thursday. He said he expected to return to Cuba on Saturday to resume the radiation treatment, and to stay there for four more days. The president started the radiation therapy last Saturday, saying he would undergo one session a day for five consecutive days, then fly home to rest for a couple of days. Overall, Chavez has said, the treatment should last four to five weeks. He previously underwent four session of chemotherapy that caused his hair to fall out but it since has grown back. The Venezuelan leader prefers being treated in Cuba because he is guaranteed discretion on the tightly controlled island and can lean on the counsel of his friend and mentor Fidel Castro. In his pre-dawn speech, in which he appeared animated and smiled and joked with his ministers, he forecast he would win the October 7 election with more than 60 percent of votes. Most recent polls have given him a strong lead over his opposition rival, youthful Miranda state governor Henrique Capriles. Analysts say his strength in the polls is due to his charisma and strong emotional connection with the country's poor majority, as well as heavy state spending on popular welfare programs. The surveys consistently show, however, that as many as a third of Venezuelans remain undecided, and both camps have been waging a fierce battle to win them over. Capriles, 39, is widely seen as the best hope the opposition has had of unseating Chavez after years of failures via the ballot box and street protests. He has set off on a nationwide "house-by-house listening tour" to kick-start his campaign. Capriles, a center-left politician who has largely avoided direct verbal clashes with the president, is promising a Brazilian-style government for Venezuela, promoting free-market economics alongside strong social programs. Chavez, known for his radical populism, nationalizations and fierce anti-U.S. rhetoric, has denounced him as the candidate of the "ultra-right" and a treasonous puppet of Washington. Additional reporting by Mario Naranjo; Editing by Philip Barbara