Health authorities in Canada tend to take several months longer to approve new cancer drugs than those in the U.S., leaving Canadian patients waiting longer for the potentially life-extending medication, a new study suggests.

Toronto-based cancer researchers Dr. Sunil Verma, from Sunnybrook’s Odette Cancer Centre in Toronto, and MD/PhD student Nardin Samuel looked at how long it took for 41 cancer drugs to be approved in Canada, and compared the approval times to those in the U.S. and the European Union.

They found that on average, the U.S. Food and Drug Administration approved drugs six months earlier than for the European Union's European Medicines Agency, and 7.6 months earlier than Health Canada.

Azactidine, a drug now approved for leukemia and bone marrow diseases, had the greatest delay between FDA and Health Canada approval: 66.1 months. Even in Europe, the EMA approved Azactidine 10.3 months earlier than Health Canada.

Another drug for metastatic prostate cancer called cabazitaxel was approved by the FDA just 17 days after the drug's manufacturer filed for approval. But in Canada and Europe, the times to approval were 11.63 months and 11.03 months, respectively.

The study, which the authors say is the first to compare cancer drug approvals between three major regulatory bodies, is being presented at the European Society for Medical Oncology’s 2014 Congress in Madrid, Spain.

The researchers note that regulatory agencies such as Health Canada and the FDA play an important role in ensuring the safety and effectiveness of new drugs. But they say that delays in drug approvals can have an impact on patient care.

"Our main aim as clinicians is to ensure that patients are given an opportunity to receive proven, effective and safe treatment in a timely manner," Verma said in a statement.

"We need to balance due diligence to review appropriate treatment by regulatory agencies and providing treatment to our patients that is effective."

Commenting on the study, Dr. David Cameron, director of the Edinburgh Cancer Research Centre in the U.K., said the findings are concerning because they suggest there may be bureaucratic reasons rather than scientific reasons for the different approval times.

The study authors say there needs to be more discussion between the pharmaceutical industry, regulatory agencies, patient groups, and researchers about how to reduce the approval times, while also ensuring safety.

In Canada, the Therapeutic Products Directorate of Health Canada assesses the safety and efficacy of drugs, sometimes with the help of outside experts.

Health Canada says the TPD has set "internationally competitive performance targets" for its conduct of reviews and that the length of time for reviews depends on the product being submitted, the size and quality of the submission, and TPD's workload and human resources.

"Currently, the process for the review of a drug takes an average of 18 months from the time that a sponsor submits a New Drug Submission until the TPD makes a marketing decision," the agency says on its website.

The TPD also has a Priority Review Process in place to allow for faster reviews for promising drugs for life-threatening conditions, such as cancer, AIDS, or Parkinson's disease.

In May, an analysis published in the Canadian Medical Association Journal found that access to new drugs in Canada was delayed by pharmaceutical company submissions to Health Canada rather than longer approval-processing times.

The authors, from the University of Calgary's department of economics, found that many smaller pharmaceutical companies lack the resources and expertise to navigate the regulatory process in countries such as Canada.

They wrote that if Health Canada and the FDA were to harmonize their regulatory processes, it would accelerate drug submissions in Canada.