Hundreds of cancer patients in Canada did not receive the full dose of three highly concentrated intravenous medications because of problems with the way they were administered. However, at least two provinces disagree on whether the patients need to be told.
The drugs, which were introduced in this decade, are for advanced cases of cancer and are given to patients in hospitals using a similar method to how chemotherapy is administered: via an intravenous tube attached to a pump. In June, Cancer Care Ontario (CCO) learned that the way some hospitals were using this system when they administered these drugs could leave small amounts behind after the treatment ended. The problem was first noticed by a health-care worker at Trillium Health Partners in Mississauga.
CCO canvassed the province’s hospitals and determined about 1,000 patients likely did not receive the full dose, with fewer than 10 requiring new treatment as a result. Patients were all informed of the medication dosing issues and had discussions with their oncologists about the impact and whether they would need supplemental treatment, according to Cancer Care Ontario.
Cancer Care Manitoba told The Globe and Mail on Thursday that hundreds of patients in the province were also affected by the dosing problem. But the agency has decided not to inform them because it believes the outcomes were likely not affected and doing so would create unnecessary alarm, said Piotr Czaykowski, chief medical officer of Cancer Care Manitoba.
“Realistically, we’re not convinced that this is actually a major issue,” he said. “We don’t think there’s evidence the variance in dosing here will have had an adverse effect on patients.”
CCO said the problem was noticed with three cancer drugs, pembrolizumab, nivolumab and panitumumab, which are used to treat various types of late-stage cancer that have spread. But some Ontario hospitals reported the problem also includes other highly concentrated cancer drugs.
The three medications are typically immunotherapy and targeted therapy drugs that are becoming increasingly common in the treatment of cancer. Unlike older chemotherapy drugs, which are administered in much higher volumes, the newer drugs are given in lower doses, meaning every drop counts.
Dr. Czaykowski said there is no evidence to show that minor changes will affect patient outcomes.
Jin Huh, senior pharmacy director at Toronto’s University Health Network, said it would be very difficult to pinpoint exactly how patient outcomes may have been affected. For instance, if a patient experiences worsening symptoms, it could simply be seen as a progression of the disease.
“I’m not sure how you would pick it up,” he said in an interview.
After learning of the problem in June, CCO reached out to counterparts across the country, as well as Health Canada, urging them to review their medication delivery systems for these cancer drugs. Some provinces responded immediately that they had no issues. But Robin McLeod, vice-president of clinical programs and quality initiatives at CCO, said that unless hospitals physically examine their medication delivery setup and report back, the cancer agencies won’t know if they have a problem.
“Until you really see just exactly how all of this is being set up and delivered…you may miss it,” Dr. McLeod said.
Cancer Care Ontario discovered that factors involved included the length of the IV tubes and the type of pumps used. One way to ensure patients receive the full dose is to put saline or another solution though the IV line to flush the remaining medication into the patient. But according to Cancer Care Ontario, this wasn’t standard at all hospitals. The drugs are highly toxic, meaning health-care workers had to be very careful not to come in contact with them and some hospitals were using IV lines that did not allow workers to flush them without risking contact.
The agency has updated its policy on the delivery of this kind of medication and is conducting an investigation to determine the causes of the problem, Dr. McLeod said.
Dr. Czaykowski said the province experienced problems similar to the ones in Ontario and has implemented changes.
A spokesman for BC Cancer said in an e-mail the province is not affected by the problem because all of its cancer centres use a system called a secondary line, which helps ensure all of the liquid in the IV bag is used. A spokeswoman with Eastern Health in Newfoundland and Labrador said in an e-mail it is standard in the province to flush IV lines. A spokeswoman with the Saskatchewan Cancer Agency said in an e-mail the province also uses secondary lines.
Carly Weeks