Chavez has not disclosed what type of cancer he has, and the Venezuelan government has released few details about his illness, fueling widespread speculation about his health and political future.
Last year, Chavez had surgery to remove a cancerous tumor and he has undergone further surgery and radiation in Cuba since. He returned to the island nation last month for more surgery after publicly revealing that his cancer had returned.
He underwent a six-hour surgical procedure on December 11 that Maduro, in a televised address, declared a success.
On Tuesday, Maduro said he planned to return to Venezuela on Wednesday and was optimistic that Chavez's health would improve.
"We have the confidence and faith in God and in the doctors that our Comandante Hugo Chavez will keep getting better," he said, "and sooner rather than later he will come out of this complicated and delicate situation he's in."