Venezuelan President Hugo Chavez will undergo cancer surgery in Cuba for the third time in eight months as early as Monday, an indication that he may be facing an aggressive tumor that could spread throughout his body, oncologists and gastroenterologists say.

In a country where Chavez makes all major decisions and pronouncements, details about his illness remain sketchy, with only the maximum leader revealing what he sees fit to disclose. But leading doctors who treat various forms of cancer, including those in the pelvic area where Chavez has been stricken, say the recent discovery of a one-inch formation points to a new, potentially critical stage for the president.

“He is facing a delicate situation, one of great uncertainty and everything points to an aggressive tumor,” said Carlos Castro, a Colombian oncologist and scientific director of the Colombian League Against Cancer. “I wouldn’t be surprised if in a few months we hear about a small lesion elsewhere in his body, in a lung, or in the liver. That’s called metastasis.”

Like Castro, Floriano Marchetti, a University of Miami professor who treats colon and rectal cancer, does not have direct knowledge of Chavez’s health. But Marchetti, too, has followed the president’s pronouncements about his fight with cancer, including the announcement last week that Cuban doctors would operate once more to remove what could be a malignant growth.

“The guy had surgery, he had chemotherapy and less than a year later he is having the same problem in the same area,” Marchetti said, speaking by phone during a break in an operation he was conducting in Miami. “That obviously is a bad prognosticating indicator.”

Facing reelection fight

Chavez, a 57-year-old leftist firebrand who has formed alliances with pariah nations ranging from Syria to Iran to Cuba, has been a political provocateur since he led a failed coup in 1992. But since June, questions about his health have dominated political discussions in oil-rich Venezuela.

That was when Chavez announced on national television that he had undergone two operations in Cuba that removed a baseball-size tumor. He never publicly disclosed what kind of cancer he had, nor the site of the original tumor.

The president later revealed that he had four chemotherapy sessions. He then pronounced himself cured of cancer and resumed a hard-driving campaign to secure victory in October’s presidential election, in which he faces a 39-year-old challenger, Henrique Capriles.

But then Tuesday, Chavez said Cuban doctors had detected “a lesion” with a high probability of being cancerous in the same spot where the first tumor had been removed.

On Thursday, his last full day in Venezuela before flying to Cuba, Chavez hosted an event for his staunch followers at a Caracas theater in which he described how Jesus Christ had come to him in a dream. “He told me, ‘Chavez, get up, it is not time to die, it is time to live,’ ” Chavez said.

Chavez also sounded contemplative, saying he was “preparing for the worst.” Speaking of the lesion, he said that “the possibility that it is malignant is greater than it not being” malignant.

Doctors consulted in Colombia, Venezuela and the United States say Chavez probably has a tumor and that it may have metastasized. The fact that a new growth appeared so soon after his chemotherapy was seen as a sign that it is a stubborn tumor.

“It is a new growth from probably the same tumor that was treated before,” said Leon Lapco, a Miami-based kidney specialist who is president of the Venezuelan-American Medical Association. He said that there is “an extremely high possibility” that other cancerous cells “are already in there, at least some cells, some malignant cells.”

The spread of the cancerous cell would depend on the type of tumor and the location, said Pedro Jose Greer Jr., a liver and digestive disease specialist in Miami.

“Some tumors spread by lymph node,” said Greer, who is also a professor at Florida International University’s medical school. “Those that spread by blood will end up in the liver and in the lungs. And some spread locally,” meaning they invade tissues adjacent to the tumor.

‘I will return’

Judging from what Chavez has said about his illness, his tumor could be in the bladder, the rectum or the colon, said Marchetti, the Miami doctor who treats rectal and colon cancer.

“Particularly, for colo-rectal cancers, 80 percent of the tumor recurs within the first two years after treatment,” Marchetti said. “The bottom line is that whatever it is, it’s a problem because now it’s back.”

Marchetti said the operation Chavez faces in Cuba, along with radiation therapy or chemotherapy, will be challenging for his medical team. “The cancer stepped up the fight, and now you have to come up with better forms of treating it,” Marchetti said. “Otherwise there will be no hope.”

Chavez, though, is planning to govern from Cuba while planning his return to Venezuela to resume campaigning for a new six-year term to extend his presidency until 2019. “I will return as I always return — with more energy, more enthusiasm and more happiness,” Chavez wrote in a letter to the National Assembly last week.

Specialists such as Douglas Leon Natera, a surgeon and urologist in Caracas who is president of the Venezuelan Medical Federation, said the president’s condition calls for him to set aside governing for now.

“He wants to transmit a show of strength to all of Venezuela’s people, followers or not, so they believe that he is full of vigor and can continue governing,” Natera said. “You are left with the impression that what predominates is politics over his own health.”