An independent review into what caused more than 1,200 Ontario and New Brunswick cancer patients to receive diluted chemotherapy drugs has concluded that the problem “boiled down to gaps in communication.”

Dr. Jake Thiessen delivered his report to Ontario Health Minister Deb Matthews Wednesday, offering his findings about what went wrong and what could be done to prevent similar incidents in the future.

He said he found no evidence of “any harmful intent” to provide diluted products or to underdose patients. But he says there were mixups in instructions on how the saline bags containing the drugs were meant to be prepared and how hospitals were meant to use them.

For more than a year, patients at four hospitals in Ontario and one in New Brunswick received chemotherapy medication that was mistakenly over-diluted with saline solution. All but 30 were cancer patients and most were adults. Many of those patients have since died, but there’s no way of knowing whether the drug dilution mix-up contributed to their deaths.

Thiessen explained that a company called MedBuy arranged the contract between the hospitals and Marchese Hospital Solutions, the facility that prepared the IV bags filled with medication. Problems began, he said, when MedBuy provided Marchese with “only a simple statement of specifications.”

While Marchese used the correct medication dosage, it failed to account for the fact that the IV bags it was using were overfilled with saline.

“The simple statement of specifications led Marchese to use a process that failed to adjust for the overfill volumes,” Thiessen said.

The hospitals didn’t correct for the overfill because they were unaware of lower concentrations, and there was no clarifying instructions from Marchese on the bags.

Thiessen found that the average amount of over-dilution of the two drugs -- gemcitabine and cyclophosphamide -- was around 7 and 10 per cent respectively.

“What was the impact of the dilution factor on patients? At this time, the impact is simply unknown,” Thiessen said.

But, he noted that the underdosing was relatively small, and the dilution affected only two of the many chemotherapy drugs most of the patients were taking. For that reason, he said, “the probability is small that the shortfall had an overall serious effect.”

Pamela Worts, one of the patients affected by the diluted chemotherapy, said Wednesday it doesn’t explain why the error was not discovered sooner.

Worts said she is still angry and distrustful over the mixup.

“Because I did everything that was asked of me to do and then I get this thrown at me just over a year from when I was diagnosed,” she told CTV News. “That just puts your whole world upside down again.”

The report’s findings have no bearing on the lawsuit she has filed regarding the matter, Worts said.

“It never needs to happen again, and in this day and age, it shouldn’t have happened this time,” she said. “With the amount of quality controls that we have in our system, in everything medically wise, they should have been there too.”

As for how to prevent future errors, Thiessen recommended that all pharmacies operating within Ontario clinics or hospitals be licensed, as most currently are not.

To that end, Matthews announced Wednesday she'll introduce legislation in the fall to authorize the province's College of Pharmacists to both inspect and license hospital pharmacies.

"Our government fully endorses Dr. Thiessen’s recommendations and looks forward to working with Health Canada and our other health sector partners to act on them," Matthews said in a statement.

As well, Thiessen recommended that Health Canada license and regulate all drug-product preparation facilities not housed within licensed pharmacies, such as Marchese.

The problem came to light in the spring when a pharmacy assistant at Peterborough Regional Health Centre caught the error after noticing some bags looked bigger than others.

Marchese is now facing several lawsuits over the errors. The company issued a statement Wednesday saying it welcomed the report.

“From the moment we heard about this issue we have all been trying to understand what went on throughout the system and to help develop and implement changes so that no patients ever have to go through an experience like this again,” Marchese said.

It added it would be reviewing the report thoroughly before commenting further.