Venezuelan President Hugo Chavez gestures before voting in Caracas on October 07, 2012. Venezuelans voted Sunday with President Hugo Chavez's 14-year socialist revolution on the line as the leftist leader faced youthful rival Henrique Capriles in his toughest electoral challenge yet.

Nicolas Maduro, Venezuela's vice president and longtime foreign minister, has been named as Hugo Chavez' preferred successor, as the South American leader faces another round of cancer treatment in Cuba.

It is the first time Chavez has named a successor, sparking concern that his illness may finally cause him to step aside. 

"There are risks. Who can deny it?" Chavez said in a televised address, seated at the presidential palace with Maduro, according to the Associated Press. "In any instance, we should guarantee the advance of the Bolivarian Revolution."

"You all elect Nicolas Maduro as president," he added.

58-year-old Chavez, who has led the OPEC nation for 14 years and was recently elected to another six-year term, returned to Havana Sunday after doctors found a recurrence of malignant cancer in his pelvic area early Friday, Reuters reported

Though doctors had reported recommended he have the surgery right away, Chavez said he insisted on returning to Venezuela first, the Los Angeles Times reported, stressing "unity, unity, unity" amongst his party. 

"Unfortunately, during these exhaustive exams they found some malignant cells in the same area. It is absolutely necessary, absolutely essential, that I have to undergo a new surgical intervention," said Chavez, according to BBC News. "With God's will, like on the previous occasions, we will come out of this victorious."

According to the Venezuelan constitution, if Chavez steps aside, new elections would have to be called within 30 days, the New York Times reported

As Reuters points out, a bumpy power transition from the charismatic politician's highly centralized rule could destabilize Venezuela's political climate and have far-reaching consequences, as the South American country holds the largest crude oil reserves in the world. 

Dr. Carlos Castro, scientific director of the League Against Cancer in Colombia, told the AP that Chavez' operation will likely be followed up by more chemotherapy. 

"It's behaving like a sarcoma, and sarcoma doesn't forgive," Castro said, adding that he wouldn't be surprised if the cancer had also spread. "We knew this was going to happen. This isn't good."

More from GlobalPost: Chavez travels to Cuba for more cancer treatment

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