The London Health Sciences Centre said Friday that 26 additional patients were identified during a second, expanded assessment of its files.
The latest discovery brings the total number of patients affected at the London, Ont., hospital to 691 — 651 adults and 40 children. The hospital said it has reached out to all of them.
Neil Johnson, the hospital's vice-president of cancer care, said they believe 117 adults among those 691 patients have died, but they can't be sure.
"Keeping track of patients who are deceased isn't always something that our hospital will know about," he said.
"If somebody has gone back to another region, they may have gone back to another area, and so those records may be incomplete in terms of who are alive and who are dead."
It's important to note that the deaths can't be directly attributed to the diluted drugs, he added.
"Our medical staff ... answered a lot of questions from patients, and they made it clear that their belief as physicians was that the likelihood of a link — or any sort of association with treatment outcomes — whether it's death or otherwise — is very minimal, if at any," Johnson said.
Marchese Hospital Solutions, a Mississauga, Ont.-based company, was contracted to prepare the chemotherapy drugs for four hospitals in Ontario and one in New Brunswick.
Too much saline was added to the bags containing cyclophosphamide and gemcitabine, in effect watering down the prescribed drug concentrations by up to 20 per cent.
Marchese said its products weren't defective, and suggested that the problem wasn't how the drugs were prepared but how they were administered at the hospitals.
But there is a gap in the oversight of companies like Marchese that mix drugs for hospitals, Premier Kathleen Wynne acknowledged Thursday.
The company falls into a jurisdictional grey area, with both the Ontario College of Pharmacists and Health Canada unable to agree on who was responsible for the facility.
The college oversees pharmacists, including those who may have worked independently for Marchese Hospital Solutions. Health Canada oversees drug manufacturers.
But Marchese wasn't considered a pharmacy or a drug manufacturer.
Health Canada argued that if Marchese was doing something that was usually done in hospital — like mixing drugs — that would fall under provincial jurisdiction.
Wynne said both Health Canada and the college are working to close that gap, and the college is willing to provide oversight of new compounding facilities like Marchese.
The government appointed a pharmacy expert, Jake Thiessen, to review the province's cancer drug system. A working group that includes doctors, Cancer Care Ontario, Health Canada and others are also looking at the problem.
Ontario Health Minister Deb Matthews thanked the "hard working staff" of the London hospital Friday for combing through their records to identify all affected patients and notifying their families.
"Those families have my commitment to determine how this happened, to ensure proper oversight of our drug system is in place, and to prevent it from happening again," she said in a statement.
Ontario's New Democrat Leader Andrea Horwath said she's "shocked and disturbed" that more patients were given weaker-than-prescribed doses of the drugs.
"It begs the question how many more people are out there who still don't know that they were given drugs that were watered down, and how many other drugs are being dispensed to patients that we don't know whether or not they're appropriately being dosed," she said.
It's "horrifying" that the Liberals said only seven per cent of Ontario chemotherapy patients received diluted drugs, Horwath said.
One person is too many people to have been given the wrong dosage of medication based on a lack of oversight by the ministry responsible," she said.
"So whether it's seven per cent, whether it's one per cent, whether it's one human being, it is not acceptable that this has happened in our province."
The Progressive Conservatives are asking a legislative committee to launch an investigation into the drug scare and whether the Ministry of Health did its job in monitoring companies like Marchese.
"People who are receiving these kinds of health-care services, especially with a cancer diagnosis, you have to have faith that there is integrity in the whole process and that you're receiving what you're supposed to be receiving," said Tory health critic Christine Elliott.
"That confidence has been undermined because of a lack of oversight by this government."
London Health Sciences Centre said they employed Marchese since March 2012 to mix the two drugs that were diluted, and Baxter Canada before that.
Under their contract, the companies were expected to adhere to the same standards that applied to the hospital pharmacy, Johnson said.
The hospital is no longer using any products from Marchese and has determined that Baxter correctly prepared the drugs they supplied, he said. All the drugs are now being prepared by the hospital.
The drug preparations weren't outsourced to save money two years ago, but to make the pharmacy's operations more efficient, Johnson said.
"These are high-volume drugs," he said.
"We want to use drugs that actually come in ready-mix solutions because that — from a work flow perspective and from a safety perspective — is for them to be more effective."