Dr. Pagliaro recommended an experimental chemotherapy regimen, and Jake has shown no sign of cancer since the treatments ended in March 2008. “Needless to say, we’re very pleased with how he’s doing,” Dr. Pagliaro said.

But during Jake’s check-up in December, Ms. Walker told the hospital that her son would be uninsured at the end of January. She said a hospital official then told her that if she was not able to pay up front, she should take her son elsewhere.

Dr. Pagliaro pledged that he would do what he could to make sure that Jake would be seen. “To deny him the relatively inexpensive follow-up that is so crucial,” he said in an interview, “just makes absolutely no sense.”

But the doctor has yet to intercede with the business office about waiving fees, saying it would be premature. Last month, when the Walkers showed up for an appointment with Jake’s oncologist, only a last-minute dispensation enabled him to be seen without payment in advance. The Walkers left with the impression they would be billed $700; the hospital says it will be $1,507. In either event, they have no way to pay it.

The hospital has suggested that Jake have his next tests elsewhere and send the results to Dr. Pagliaro to review, with payment to be negotiated in advance.

The Walkers are now completing the voluminous paperwork to apply for M. D. Anderson’s charity care program for Texas residents. The hospital, which had $2.2 billion in net patient revenue last year, spent $209 million on such uncompensated care.

But Dr. Ron Walters, the hospital’s vice president for medical operations, said economic pressures had made it more difficult to assist patients who were not under active treatment. Dr. Walters said it had been “good financial counseling” to advise the Walkers to explore other options, and questioned whether they would qualify for charity care because they had assets. Among the criteria, he said, is whether a patient can receive comparable treatment elsewhere.