Published: Jul 13, 2011 8:48 PM EDT
Updated: Jul 13, 2011 7:49 PM EDT

CARACAS, Venezuela (AP) - Nearly two weeks after announcing he has cancer, President Hugo Chavez on Wednesday described a baseball-sized tumor that was removed in surgery and a prognosis that includes chemotherapy or radiation treatment.

Chavez provided his most extensive account to date of his illness, suggesting that difficult months may lie ahead as he anticipates physically taxing treatments while also remaining in the presidency. It was the first time he has referred to expecting chemotherapy or radiation treatment following the June 20 surgery in Cuba.

Chavez said in a phone call to state television that he is now starting a second phase of treatment and expects a third phase "that could be a bit hard." He said the purpose would be to "armor the body against new malignant cells of this type."

"It would most likely require the use of methods that are known ... depending on the evolution and these follow-up diagnoses, but it could be radiation therapy or chemotherapy," Chavez told state television in a phone call.

Chavez said such treatment would be to "attack hard, with cavalry, any possibility, anything latent that might be there." He did not say how soon such treatment might begin.

Chavez still did not say what sort of cancer is involved.

He said the operation lasted about six hours and removed a tumor that was "encapsulated."

"I had a big, big tumor," Chavez said. "When I saw that image, I said, 'My God, it's a baseball.'"

Since his return to Caracas on July 4, the 56-year-old president has limited the length of his televised appearances, saying he is under strict orders from his doctors.

Chavez said Wednesday that he is recovering well, and suggested some of his foes hope he does not.

"I have cancer, but not in the way some would want," Chavez said.

He earlier said that the operation was in his pelvic region, but denied on Wednesday that his colon been cut during the surgery.

That implies Chavez could have suffered bladder, kidney, prostate or even rectal cancer, although doctors consider the rectum part of the colon, said Dr. Michael Pishvaian, a cancer specialist at Georgetown University's Lombardi Comprehensive Cancer Center who was not involved in the Venezuelan leader's treatment.

Another possibility is a sarcoma, a soft-tissue cancer that can occur anywhere in the body and that often is encapsulated, or contained within a pouch of tissue.

Radiation is given to kill any remaining tumor at the original site; chemotherapy is to treat any tumor that has spread or to kill stray cancerous cells that might seed a new tumor.

"He's essentially probably getting these treatments in the hopes of preventing any recurrence of the disease," Pishvaian said. "The idea is to try to eradicate any microscopic disease that might be present."

Radiation typically involves daily treatments for four to six weeks. Chemotherapy is given periodically for about six months, depending on the regimen and how well the patient tolerates treatment, Pishvaian said.

Chavez said his first phase of post-surgery treatment has turned out well, "thanks to God and to medical science, and to this body, which seems tougher than what I myself believed."

Chavez also said, however, that he is constantly observed by a doctor and a nurse who accompany him even at night, and that he undergoes regular evaluations because "the threat of ... expansion, outbreak is always latent."

Foreign Minister Nicolas Maduro said earlier this month that the operation to extract the tumor was performed in the same area as another surgery nine days earlier to remove a pelvic abscess.

Maduro said that specialists had confirmed after the operation that "the entire abscessed tumor was able to be removed, all of his organs were checked, that they are in perfect shape."

Chavez said Wednesday that he has achieved a "recovery of vital signs, well, recovery of weight, recovery of all blood levels," though he said he was still about 31 pounds (14 kilograms) below his earlier weight.

"I'm now getting close to my weight of 85 (kilograms)," or 187 pounds, Chavez said. "I was at more than 100 kilos (220 pounds) ... I looked like a battle tank."

Chavez, who is up for re-election in late 2012, has been actively posting messages on Twitter and has appeared on television in the past several days leading a Cabinet meeting, doing stretching exercises with aides and attending Mass.

Chavez, a former army paratroop commander, has said his rehabilitation regime requires discipline, including waking up at 5 a.m. That is a significant change for a president known for speaking regularly late into the night and summoning his ministers at all hours.

Chavez said cancer has led him to reflect about what he called "fundamental errors" in his lifestyle, such as drinking "40 cups of coffee in one day," carrying three cell phones, eating whatever was available and "not sleeping, not letting my ministers sleep."

He also acknowledged it has been a serious mistake to be habitually "talking too much."

Chavez has said his doctors have advised him to limit the length of his televised talks, which in the past could run as long as seven or eight hours.

"I'm on that, slowing down the horses I lead, but learning. I'm learning. I have to learn to delegate more," Chavez said.

The president attended Mass on Tuesday night at Caracas' Military Academy, joining friends and aides in praying for his recovery.

Chavez led a brief prayer and then closed his eyes as he listened to the Rev. Mario Moronta, who said he would administer the sacrament of anointing the sick to Chavez.

The priest, a friend of Chavez, said the sacrament is "for the sick or elderly person to have strength ... to beat the illness."

"There is no need to be afraid. Six years ago they did it to me twice. I was more there than here, and look where I am," Moronta said. "Sometimes I myself have seen people who have stood up from their sick bed in a moment of difficulty because it's celebrated with faith."

He made a cross in oil on Chavez's forehead. Visibly moved, the president put his palms together and hugged the priest.

Chavez was once an altar boy, but has clashed in recent years with some Roman Catholic leaders in Venezuela, accusing them of lying about his government. Nevertheless, he says he remains a Christian and once called Jesus "the greatest socialist in history."

Chavez also said in separate remarks to state television on Tuesday that he intends to remain in the presidency and accelerate his drive for socialism in Venezuela.

(Copyright 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)