Guerrero announced his decision last Tuesday, a week after he was forced to drop our of a proposed bout with Micheal Katsidis.
Casey Guerrero is in hospital as she recovers from a bone-marrow transplant and chemotherapy.
Guerrero, who has a record of 25-1-1 with 17 knockouts, won a featherweight title before his wife was diagnosed with the disease in 2007.
He vacated that title in 2008 to move up to super featherweight, and claimed the IBF title last August with a 12-round unanimous decision over South African Malcom Klassen in Houston.
The Guerreros, who hometown is just south of the San Fransisco Bay Area, have two small children, Robert Jr. and Savannah.
Guerrero was scheduled to fight Katsidis on March 27, in what would have been a major break in his young career.
“Robert still wanted to fight,” manger Shelly Finkel said last Tuesday. “But when we called him, he said, “No, you’re right. My mind won’t be there”.
Casey Guerrero’s cancer went into remission and there was optimism she had beaten it, but it returned in the past few weeks.