Sir Richard Hadlee will undergo surgery after secondary cancer was discovered in his liver.
Hadlee has been undergoing treatment for bowel cancer.
Lady Dianne Hadlee said the medical advice was that the cancer was very early stage and is operable.
The former cricket all-rounder had a routine, three-year colonoscopy in May where a tumour was discovered.
He has since had a successful operation to remove it, and has been undergoing chemotherapy that was expected to last a few months.
Lady Dianne said: "As with the first statement released on this matter, we disclose these details solely in the interests of transparency, and to avoid speculation and gossip.
"We would again ask that people respect our request for privacy."