TORONTO - The agency that oversees cancer care in Ontario says a review found hundreds of patients did not receive full doses of cancer drugs because of issues with how the intravenous medications were administered.

Cancer Care Ontario says that out of the nearly 1,000 people affected, less than ten needed to receive additional treatment as a result.

But the agency says the matter is being taken seriously and guidelines for hospitals on how such drugs should be administered are being updated.

The dosing issue first arose in June when the Mississauga Hospital west of Toronto notified Cancer Care Ontario of medication being left behind in intravenous tubes after patients received treatment.

Cancer Care Ontario says it immediately asked all 74 Ontario hospitals that deliver cancer drug treatments to review their procedures to ensure medication was being administered properly.

The agency says 35 hospitals reported back saying they found issues with how three drugs were being given to cancer patients.