Dr. Jill Nation told a hearing on whether the trial should proceed that Aset Magomadova, who is 43, was diagnosed with cervical cancer a year ago.
Despite eight weeks of radiation therapy, the cancer had spread to the lymph nodes in her lower abdomen within a month.
"What it told us was she had an extremely aggressive form of cancer," said Nation, who is a gynecological oncologist at Calgary's Tom Baker Cancer Centre.
"Normally you would have had a period of so-called remission (after treatment)."
The defence is asking the charge be stayed, saying Magomadova is too ill to go to trial.
Magomadova, who was wheeled into the courtroom on a gurney, was initially charged with the murder of her daughter Aminat in 2007, after the girl was choked to death with a scarf.
The Chechnyan woman argued she strangled her daughter in self-defence after Aminat began attacking her.
Magomadova was found guilty of manslaughter at the conclusion of her trial in 2010 and given a suspended sentence and three years probation, but the Alberta Court of Appeal ruled the trial judge erred by failing to consider Magomadova's intent and a retrial was ordered.
The Crown filed notice it would argue the sentence was not proportional to the gravity of the offence and the culpability of the offender and the sentence didn't adequately deal with "deterrence, denunciation and retribution".
The retrial was originally scheduled to begin in May 2012, but proceedings were postponed after Magomadova was diagnosed with cancer. It had been rescheduled for this week but is again on hold while the current application is dealt with.
Although she is now receiving monthly chemotherapy treatments, Nation said the prognosis is dismal.
"Her condition is palliative and once it is palliative the likelihood you are going to cure that cancer decreases dramatically," Nation said.
"We deal in probabilities. We talk about five year survival rates," she said.
"The five year survival rate is less than one per cent. In the next five years it will probably knock off the remainder."
Nation said the treatment Magomadova is now receiving is meant to achieve "some degree of remission" in the disease and is aimed at giving her a better quality of life.
She testified it was unlikely that Magomadova would be able to endure another six-week trial.
"In my opinion medically she would not be able to," she said.
If the stay of proceedings application is unsuccessful a new trial date will again have to be scheduled for later this year.
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