"At this point and time surgery is not the best option for Jim," Jill Kelly wrote on her Facebook page. "The cancer is in areas that surgery cannot successfully eradicate."
Kelly was initially scheduled for five to six weeks of chemotherapy after his surgery, which his wife had said in an Instagram update was "tentatively scheduled for Thursday."
Along with her latest Facebook update, Jill Kelly posted a picture of her husband hugging his father from his hospital bed in New York City.
"Jim Kelly's condition remains very treatable and potentially curable," said Dr. Peter D. Costantino, who will direct Kelly's treatment at Lenox Hill Hospital. "Our immediate focus is on controlling his pain and beginning the process of eradicating the cancer."
Kelly learned on March 14 that cancerous cells, which doctors removed from his jaw in June 2013, had returned. His wife said in a blog post last week that the cancer was "aggressive" and "starting to spread."
The 54-year-old Kelly, who was inducted into the Pro Football Hall of Fame in 2002, has received prayers and support across social media. The news of his surgery being canceled comes one day after Bills founder and owner Ralph Wilson died at age 95.