"At this point and time surgery is not the best option for Jim," Jill Kelly wrote on Facebook. "Because of (the) complexity and aggressive nature of this cancer and after more scans and tests, the plan has changed.
"The cancer is in areas that surgery cannot successfully eradicate. Therefore, the medical specialists here in (New York City) along with our Buffalo team believe that chemotherapy and radiation are the best option."
Kelly was tentatively scheduled to have surgery on Thursday after doctors said they discovered during a checkup that his cancer had returned. Jill Kelly has said the cancer is "aggressive" and "starting to spread."
Kelly, who spent his entire NFL career with the Bills from 1986-96 and led the team to four consecutive Super Bowl appearances, had surgery last June after he was diagnosed with cancer in his upper jaw bone.
At the time, the cancer was isolated and the former quarterback said doctors considered his prognosis for recovery to be "very good."