The CBC has learned that Susan D'Aloisio admitted to falsifying records of patients' vital signs for at least seven years, before she was let go last year.
According the agency, concerns about D'Aloisio were first raised by a co-worker last May, prompting an agency-wide audit and an investigation by the College of Registered Nurses of British Columbia.
As a nurse in the clinical trials unit D'Aloisio recorded patient data critical to assessing new drugs and therapies used to fight cancer.
Fiona Walks, a vice-president with the Cancer Agency, says an audit showed the records of dozens of patients were affected. But she says no patients were ever at risk, because patient vital signs were also checked by doctors.
"It certainly is a breach of trust and it's something that we've taken very seriously, and of course it did give us pause for thought and reflection," said Walks.
"All of us in leadership positions took a step back and worked with those who deliver care to patients, especially in the clinical trials area. We reviewed our safety processes. We reviewed our clinical care processes and also looked at our culture of safety."
Drug research affected?
But the agency was also worried about the impact on the integrity of drug research. D'Aloisio is listed on several research papers about cancer drugs posted on the internet.
"After our review we took it upon ourselves not just to notify the College of Registered Nurses, but certainly our clinical trial sponsors."
Walks says the sponsors also conducted their own investigations.
"No one wants to ever see this happen in their organization, and unfortunately, this happened in our organization."
D'Aloisio has now been banned by the B.C. College of Nurses from practising in a research setting, and before she can work as a nurse again she will need to complete remedial education.
Walks says she can't say what the motivation was for D'Aloisio to falsify the patient records.
"I'm coming up on my 30th anniversary of graduating as an RN myself and I have never seen something like this before."