A medical team at the Washington Hospital Center is struggling to keep alive a 16-year-old welfare mother stricken with a rapidly growing malignant brain tumor that threatens to end her life and that of her unborn second child.

Carol Kent lies in bed 28 of the hospital's Surgical Intensive Care Unit, tubes snaking from her body, a mechanical respirator aiding her lungs, while physicians work to buy the three weeks they say is needed to give her baby a good chance of survival.

Those efforts do not come cheaply. Doctors in four specialties are waging the struggle, whose outcome is at best in doubt. The cost of her treatment now totals $30,901.60 and could well triple before the saga ends.

That struggle has now reached a critical stage, for Kent's body can stand only three more radiation treatments -- her only defense against the tumor.

Were her baby delivered today, 26 weeks after it was conceived, its chances of survival and normal development would be slim. But in another three weeks, those chances will leap to about eight or nine in ten.

"What we do is treat the patient primarily, and think about the fetus secondarily," said Dr. Michael Dennis, the neurosurgeon who is treating Kent. "If we can avoid damage to the fetus, fine. But if we can't pull the patient through, then we don't have a viable fetus."

Dennis believes Kent has about one chance in 10 of surviving her illness, although he admits survival can mean anything from a vegetative state to a normal life with slight hearing loss.

But Dr. D. E. Sabatini, chief of radiation therapy at the Hospital Center, is not nearly as optimistic.

"The patient is basically dying," he said yesterday. "She's doing really poorly. We would normally expect some improvement (at this point) but so far there has been no improvement.

"In this case we're just trying to the baby a chance, said the radiologist. Short of a miracle, he says, he sees no hope of a cure.

According to Kent's mother, the young woman's problems began late last spring with blurred visions and headaches.

Kent was taken to a suburban Maryland hospital where "they put her in the psycho ward, the nervous breakdown peoples' ward," said her mother. Carol was in and out of hospitals all summer, her mother said.

What Carol Kent has is a "highly anaplastic malignant tumor classified as medullablastoma," said Dennis.

The tumor, he said, lies in an unusual location, in the brainstem between the cerebrum and the cerebellum, right in the center of what is, in effect, the "switching center of the brain," and is now jamming and scrambling impulses the brain sends to the body.

"The location makes it difficult to approach" surgically, said Thomas, and "It's not separable from the brain. It has infiltrated normal brain tissue," so surgical removal is impossible.

On Aug. 3, two days after Kent's admission to the hospital, she underwent surgery during which a drainage tube was placed in her head to allow fluid -- building up because the tumor was blocking normal drainage -- to flow from her head back into the circulatory system.

The operation was a success, said Dennis, and "she began to respond" slightly.

"The question was," he added, "where do we go from there? Use radiation? Do nothing? Wait for the baby to be born."

To make matters even more difficult, Carol Kent's tumor is one which grows wildly during pregnancy, although no one knows exactly why.

The decision was made to wait until the baby could be delivered before starting radiation therapy, "but it didn't work out that way," said Dennis. "She began to deteriorate again. We had no options. A tumor of this sort would have killed her long before this (without radiation) so she was started on radiation."

Sabatini, who is in charge of that therapy, said "we're . . . treating her with large doses . . . because the tumor is considered radiosensitive. But so far there has been no progress."

Dennis views things more optimistically, thinking it unlikely there would be any signs of progress in the first week or two anyway.

That's true under normal circumstances, said Sabatini, but not in a case like Kent's.

"Normally, when we treat a patient who is not comatose, we give a dose of about 200 rads a day, and for the first or second week we don't get improvement. But I've doubled the dose because the patient is dying, and we should have improvement but we don't."

Although Sabatini sees virtually no chance that Carol Kent will survive, Dennis gives her one chance in 10.

"We had a 23-year-old who came in, with a similar tumor," but not pregnant, said Dennis. "She was comatose and she had a (cardiac) arrest right after surgery. She was on a respirator. . . . She left the hospital (eventually) and she lived for four years. She was deaf, and her pupils were fixed and dilated, but she was able to take care of her children for three or four years.

"As long as you think there's a chance for viable recovery," you keep trying. "We're trying to get a viable patient and a viable fetus."

Dr. James Brew, the obstetrician on the case, sees Carol Kent, rather than her fetus, as the primary patient.

"We've got to do what ever's best for the mother," said Brew who said he doesn't think there's a "valid possibility" that physicians would end up choosing between the baby and the mother.

"The obstetrician is interested, like everybody else, in obtaining a good outcome for the mother and baby. We originally thought the baby would be viable after 28 weeks of gestation," he said, "but the baby was examined with ultrasound (a technique using soundwaves to look inside the uterus) and we now think we're about three rather than two weeks away from viability."

The fetus, said Brew, is small for its gestational age, and therefore he would rather wait to attempt the delivery. "I have placed a note in the chart that we are interested in attempting a postmortem cesarean section (if the mother dies before delivery). After we reach viability, we have other options."

It may be possible, said Brew, that delivering the baby could prove beneficial for Carol Kent, because it would be far easier to nourish her alone without the caloric drain of pregnancy.

The treatment of Carol Kent is a trip down a road with many forks, said Brew. "Our immediate fork is what we're doing now. We don't know what lies at the next one."

Dr. Milton Werthmann, chief of neonatology, is the one specialist whose primary concern is the health of Carol Kent's fetus, rather than Carol Kent.

"What we would consider the earliest range of viability is 26 weeks" said Werthmann. "At that point the baby (might) have enough lung substance so it could make it. At 28 weeks its chances might be 50-50, and they dramtically improve from that point on.

Kent has not been receiving medication which is known to effect the development of the fetus, said Werthmann, and her abdomen has been shielded from the radiation her head has received.

If Carol Kent delivers her baby in the next few weeks the costs of treating the baby will range from high -- a probable bare minimum of $20,000 worth of intensive care -- to astronomical -- about $50,000 for two months or more in the nursery.

"But the expense of not (providing the special) care is that the child may still survive, but be damaged and institutionalized. That can cost $500,000 over a life time," said Werthmann. At this point however, he said, he had no reason to think Carol Kent's baby will not be relatively normal.