Dr. Carlos Castro, scientific director of the Colombian League Against Cancer in Bogota, Colombia, said that given the government's accounts that Chavez is undergoing "complex" treatment, he thinks he likely will have to step down.
"Unfortunately, the cancer he has isn't going to go away, and he's returning to continue his battle. But I think he's conscious that he isn't going to win his fight against cancer, as much as he'd like to win it," Castro told the AP in a telephone interview.
Based on the government's accounts, doctors must have performed a tracheotomy on Chavez, cutting an opening in his windpipe to facilitate breathing, according to Dr. Jose Silva, a pulmonary specialist and president of the Venezuela Pulmonology Society. Silva said he thinks Chavez is breathing with the help of a ventilator through a tube attached to his windpipe.
Patients with breathing problems often require a tracheotomy to avoid damage to the vocal chords when a ventilator is used for an extended period.
The Venezuelan Constitution says that if a president dies or steps down, a new vote must be called and held within 30 days. Chavez raised that possibility before he left for Cuba in December by saying that if necessary, Maduro should run in a new vote to replace him.
Chavez's return could be used to give a boost to his would-be successor and gain time to "consolidate his alternative leader" ahead of a possible new presidential vote this year, said Luis Vicente Leon, a Venezuelan pollster and political analyst.
Maduro and other Cabinet ministers held hands and prayed in a televised gathering on Monday night where a priest and a minister offered words of thanks for Chavez's return.
In a letter to Chavez that was read on Cuban state TV and radio, retired leader Fidel Castro said he was pleased that Chavez was able to return home.
"You learned much about life, Hugo, during those difficult days of suffering and sacrifice," Castro wrote.
Venezuela's opposition, which has strongly criticized what it calls the undue influence of Cuba's leaders during Chavez's long absence, responded to the news saying that it's natural for the president to be back in his own country and that creating a "spectacle" with his return serves no useful purpose.
"The government should tell the truth and dedicate itself to working to confront Venezuelans' serious problems," the opposition coalition said in a statement. It cited problems such as violent crime, food shortages and soaring inflation.
The 58-year-old president hasn't spoken publicly since he left for Cuba on Dec. 10. He underwent his fourth cancer-related surgery on Dec. 11, and the government says that he is now breathing through a tracheal tube that makes talking difficult.
Associated Press journalists Anne-Marie Garcia and Andrea Rodriguez in Havana, Cesar Garcia in Bogota, Colombia, and Vicente Marquez in Caracas contributed to this report.
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