It is unclear how or when the cancer was discovered. McDonald's declined further comment, citing Mr. Bell's privacy.
"During his recuperation, which is expected to be brief, Mr. Bell remains President and Chief Executive Office," said the statement. "He has expressed great confidence in his management team's ability to stay focused and continue the momentum that is revitalizing McDonald's business results."
Mr. Bell was elevated to his current post April 19 after Mr. Cantalupo died of a heart attack in Orlando, Fla., during the company's worldwide convention. Senior board member Andrew McKenna was named non-executive chairman.