His latest operation suggest the president's odds of survival are worsening, doctors say. The fact that his cancer has returned twice after undergoing four surgeries and treatment like radiation therapy and chemotherapy that Mr. Chávez has said he had indicates the cancer is aggressive and unlikely to be cured, the doctors say.

"There is no question that a recurrence now is an ominous sign. Any additional procedures are palliative in the sense they are to prevent symptoms from getting worse, rather than curative at this stage," said Michael Pishvaian, an oncologist at Georgetown University's Lombardi Cancer Center

Venezuelan President Hugo Chávez's cancer is most likely terminal given the disease's recurrences, and while the president may bounce back for periods, his health is increasingly at risk, say several leading cancer specialists not involved in the treatment.