The Alberta Cancer Board has launched an investigation into what it admits was a "most unfortunate incident" that led to the fatal overdose of an Edmonton cancer clinic patient.

The patient, a woman in her 40s, was being treated at the city's Cross Cancer Institute. She was sent home on July 31 with chemotherapy medication and an electronic pump intended to administer the dosage over a period of four days.

The pump, however, was programmed incorrectly and delivered the entire dosage over four hours.

"I guess she had it beat, she had high hopes, and then for this to happen - it's shocking," Josette King, a friend of the woman's family, told CTV news on Thursday.

The woman died Aug. 22 from multiple organ failure and internal bleeding in the intensive care unit of the University of Alberta Hospital.

Dr. Tony Fields, vice president of the cancer board, described the incident as his "worst nightmare," and said he's concerned it will shake the confidence of other patients.

"We will do our best to help patients that have doubts and fears, and to counsel them," Fields told a press conference on Thursday. "We feel that the greater importance is for our patients to know that if we slip, we will not hide it."

An investigation has been launched by the Institute for Safe Medication Practices, and the findings will be made public in about two months.

However, Alberta Premier Ralph Klein called the incident "a tragic problem due to a human error."

The patient, a wife and a mother of three teenagers, suffered from nasopharynx cancer -- where the cavity of the throat and nose meet. She had already received radiation and chemotherapy.

"Her cancer was advanced but it was not beyond cure," said Fields. "She was being treated with the expectation of a cure."

The woman's funeral was held Thursday. Her family requested that her name not be disclosed.

Fields said the two veteran nurses who made the programming mistake are highly trained, and funding pressures had nothing to do with the patient's death.

Fields said the nurses were devastated over the mistake.

Experts say the practice of sending patients home with infusion pumps to self-administer medication is a trend that they're seeing more and more.

Dr. Carol Sawka, vice president of clinical programs at Cancer Care Ontario, said the educational requirements and series of responsibilities for health care professionals responsible for the delivery of such systems vary from province to province.

While she didn't know about the specifics of the Edmonton case, she said that "generally, there's a whole system of people who are engaged in taking the treatment through -- right from the doctor's prescription to the delivery of the pump."

Sawka said cancer patients undergoing chemotherapy should know that though it is almost always a safe treatment, there is room for human error.

"The issue is that chemotherapy is a toxic treatment, it requires multiple health care professionals interacting and every time that happens there is room for human error," she said, appearing on CTV's Canada AM.

With a report by CTV's Sarah Galashan and files from The Canadian Press