The 49-year-old singer on Christmas Eve announced that she was rescheduling an unspecified number of concerts as doctors told her she needed an operation "soon."
Then, she insisted that she would not comment further, Janet released a new message late Wednesday to refute reports on her condition.
"The rumors are untrue. I do not have cancer," Janet said in a video message on Facebook. She still did not specify her ailment.
"I'm recovering. My doctors have approved my concerts as scheduled in Europe, and as I promised, the postponed shows will be rescheduled," she said, giving a clearer indication on when she will resume her tour.
Janet is due to open the European leg of her Unbreakable album's tour on March 30 in Birmingham, England.
She has more than two months of concerts scheduled before then around North America.
Janet began her tour on August 31 in Vancouver and has already performed extensively across North America, along with several dates in Japan.
She released the update on her health through social media in the form of a silent message on a black screen at the end of a two-minute video.
The clip begins with a snippet from her song The Great Forever off her latest album, in which she sings, Not too pleased with what you're digging / I'm just busy living my life.
Janet had temporarily retreated from the public eye after her brother Michael Jackson died in 2009 but returned two years later with a global tour.
Unbreakable, with a sound often eerily reminiscent of her late brother's, is her first album since the King of Pop's death.
Janet in the 1980s became a superstar in her own right, pursuing elaborate stage formations and socially conscious messaging on works such as Rhythm Nation.