Connecticut may continue to demand that a teenager undergo possibly life-saving chemotherapy procedures because she is not mature enough to undertake such a medical decision on her own, the state's Supreme Court has ruled.

The 17-year-old girl, named in court documents as "Cassandra C.," received a diagnosis of Hodgkin's lymphoma in September.

Without chemotherapy, she would likely die within two years. Chemotherapy could, however, offer her an 85 percent chance of survival, medical experts testified.

The teen has attempted to avoid the chemotherapy treatments.

Assistant public defender Josh Michtom, representing Cassandra, would not explain why she is refusing treatment, but her mother Jackie Fortin said her daughter does not want to have "poison" put in her body.

At one point, the teenager ran away from home to avoid the treatments, which the state Supreme Court cited as one example of her lack of maturity.

The patient finally underwent mandated chemotherapy for three weeks, but then failed to appear for follow-up appointments, at which point the Connecticut Department of Children and Families requested temporary custody of Cassandra, removing her from her mother's home and placing with a relative.

At Connecticut Children's Medical Center in Hartford, surgeons implanted a port in Cassandra's chest to administer chemotherapy medications. On Dec. 18, 2014, daily chemotherapy treatments began, treatment that is continuing despite her legal efforts to end them.

John E. Tucker, assistant Connecticut attorney general, in his testimony before the Supreme Court, put Cassandra's mother at the center of the controversy.

"The mother took the front seat on this," he said. "She (Fortin) didn't bring her to the first medical appointment."

"The child was very quiet, did not engage in conversations during the medical appointments," Tucker said, characterizing that as "a little bit unusual" for a 17-year-old.

"Really, the mother did all of the talking and sort of the fighting with the medical personnel," he said. "And so, really, the child stands in the shadow of her mother here. She's not an independent decision-maker.

"It was really the mother driving the bus."

Fortin has denied putting pressure on her daughter to attempt to refuse therapy.

"I am not coercing her at all and that is what this is about, what they think I am doing," Fortin told NBC News.

"My daughter does not want poison in her body," Fortin said. "This is her constitutional right as a human being."

Arthur Caplan, founding head of the division of bioethics at NYU Langone Medical Center, said Cassandra, being only 17 years old, is still too young to make a life-and-death decision.

"Respecting choice is important," Caplan wrote in an opinion piece. "Not burying a young teenage girl who would have lived is far more important."