Chávez Goes to Cuba for Cancer Surgery CARACAS, Venezuela - President Hugo Chávez of Venezuela arrived in Cuba early Monday to have surgery for what appears to be an aggressive form of cancer, leaving behind a nation hanging on the outcome of his treatment. He was greeted by President Raúl Castro of Cuba at the airport in Havana, news agencies reported, while President Rafael Correa of Ecuador flew there as well, saying that he had gone to support Mr. Chávez and hug such "an extraordinary human being," according to the Venezuelan information ministry. Back home, Mr. Chávez's supporters prayed for his recovery as opponents tried to adjust to what could be a vastly changed political landscape two months after an electoral defeat left them demoralized and scrambling to keep from losing more ground. On Saturday Mr. Chávez, 58, a fiery leftist who has used Venezuela's oil riches to steer the country toward his very personalized vision of socialist revolution, announced that an examination in Cuba had found malignant cancer cells that required immediate surgery. He also said that he was often in acute pain. For the first time Mr. Chávez named a political successor, asking his followers to throw their support behind Vice President Nicolás Maduro, and spoke about the possibility that he might not be able to continue as the nation's leader if his health deteriorated. Dr. Julio Pow-Sang, chairman of urology at the Moffitt Cancer Center in Tampa, Fla., said the most likely possibility was that Mr. Chávez was having a recurrence of cancer, in which case "the outlook would be very poor." Dr. Pow-Sang has not been involved in Mr. Chávez's care, but, noting that Mr. Chávez was first treated in June 2011, he said, "The whole process has taken no more than a year and a half, as opposed to some cancers which are very protracted and could take years." The apparently rapid timeline, Dr. Pow-Sang said, did not suggest a good prognosis. Given that Mr. Chávez already has had at least two cancer operations and chemotherapy and radiation treatment, the purpose this time is more likely to be palliative - to relieve symptoms - than an attempt to cure the disease, Dr. Pow-Sang said. Dr. Edward W. Greeno, medical director for oncology services at the University of Minnesota, seemed to agree. "My guess would be, if he's had several surgeries and at least one extended course of chemotherapy and some radiation, it's probably bad," he said. Usually, our opportunity to cure people of cancer comes with the first one or two things we do, and after that it's just controlling the disease. Dr. Greeno added that Mr. Chavez's prominence and the pressure to save him might inspire measures that are actually ill-advised. "When you get into the care of high-profile people," he said, "you may have people doing things that aren't a good idea, like picking out bits and pieces of somebody's cancer where it's not a good therapy, where we wouldn't say it's curative." Only two months ago, Mr. Chávez stood in triumph on the balcony of the presidential palace, waving to masses of red-shirted supporters after winning re-election to another six-year term. His allies called it a perfect victory. Now Mr. Chávez's apparent turn for the worse - and the possibility that he will soon be forced off the political stage by ill health - could change that. Mr. Chávez is scheduled to be sworn in for his new term on Jan. 10. But if he is too ill or if he becomes incapacitated in the first four years, new elections would be called. Venezuelans on both sides of the political divide said the country was on autopilot waiting for news of Mr. Chávez's health. "Not just in Venezuela, but the whole world is focused on him and his sickness," said Haidé Bastardo, 47, of Carúpano, in the eastern part of the country. Ms. Bastardo said that she had voted against Mr. Chávez but hoped he would recover. If he has terminal cancer, however, she said he should step down to make way for new elections. José López, an airport porter from La Guaira, near Caracas, said that as a supporter of Mr. Chávez, he was deeply worried. "You don't know what will happen in Venezuela if something tragic were to happen to the president," he said. You don't know how Venezuelans would react. Since Mr. Chávez's cancer was discovered in June 2011, he has refused to reveal details about his illness, like what kind of cancer it is and where it was found. On Sunday, when legislators unanimously gave approval for Mr. Chávez to travel abroad for treatment, an opposition lawmaker, Julio Borges, criticized the secrecy around the president's illness. "Venezuela has a right to know the truth," Mr. Borges said, according to The Associated Press. William Neuman reported from Caracas, Venezuela, and Denise Grady from New York.