Band members Mick Fleetwood, Stevie Nicks and Lindsay Buckingham said in a statement Sunday that they're sorry to cancel the 14 show dates and hope "fans everywhere will join us in wishing John and his family all the best."
Band spokeswoman Liz Rosenberg did not specify what type of cancer McVie is treating.
Fleetwood Mac recently finished a European tour. The New Zealand and Australia shows were scheduled through Dec. 7 (Watch them discuss the tour below). The band is also set to perform in Las Vegas on Dec. 30.