( CNN ) -- Venezuelan President Hugo Chavez is expected to begin radiation treatment Sunday in Cuba , where he underwent cancer surgery late last month . Chavez flew to Havana late Saturday night . His treatment is expected to last about a month , he said in a message on state media before departing . In February , Cuban doctors removed a tumor , which Chavez said was smaller than another tumor removed in June . `` I 've decided , based on the recommendations of my medical and political teams , to begin ... radiation therapy as a complement to the surgery I had four weeks ago , '' the president said during comments broadcast by the Venezuelan state-run news channel VTV . Chavez has not specified the type of cancer he is battling , and the government has released few specifics , fueling widespread speculation about his health and political future . The 57-year-old outspoken , flamboyant socialist leader has led Venezuela since 1999 and has pledged to run for re-election in October . His trip comes at the same time Pope Benedict is scheduled to visit the Caribbean island . The pope , who is on a six-day tour of Mexico and Cuba , is expected to visit Santiago de Cuba and Havana next week . CNN 's Patrick Oppmann contributed to this report .
Chavez has not specified the type of cancer he is battling . The charismatic and controversial leader is up for re-election in October .