LINCOLN, Neb. — Authorities are urgently searching for a 4-year-old Nebraska boy and his mother, who has been charged with child abuse for allegedly ending her son's treatment for cancer and fleeing the state.

A social worker reported that Prince Rehan missed several appointments at an Omaha hospital for treatment of Rhabdomyosarcoma, a rare but treatable form of cancer that forms in the soft tissue, according to Lincoln police investigator Luis Herrera.

The social worker said the boy would likely die within six months to a year without treatment, and that the cancer could become more resistant by missing appointments even after treatment resumes, the Lincoln Journal Star reported.

The boy was supposed to have weekly appointments in Omaha and four to five chemotherapy treatments in Lincoln, Herrera said.

Police on Oct. 9 spoke with the boy's father, who said the boy's mother, Abak Rehan, took their son to Arizona to get a second opinion because the treatments were making him sick. When Rehan called Herrera on Oct. 18, he asked if she was getting medical treatment for their son but she refused to discuss it, according to an arrest warrant issued Thursday.

"She was asked again and she would not answer, then later indicated she would not be returning to Nebraska," Herrera said.

Rehan, 32, told the boy's father that she didn't like the care the boy was receiving and didn't want to continue with treatment, Herrera said. He said it doesn't appear that Prince is receiving any medical care, as the boy's medical reports haven't been requested by any medical facility or provider and there hasn't been any activity detected on his Medicaid account.

In a court affidavit, Dr. Melissa Acquazzino, of Nebraska Pediatric Practice, said the boy is in imminent danger. She put his chances of being cured at 60% with treatment and 0% without it. Acquazzino said she believed it a "matter of immediate and urgent necessity" that the child be placed in the custody of the Nebraska Department of Health and Human Services.