Medication errors common in outpatient cancer treatment, study says

Mistakes in medications given to cancer patients in clinics or at home are more common than previously thought, according to a study led by University of Massachusetts Medical School researchers.

Wrong doses or other errors occurred in 7 percent of adults' chemotherapy visits and 19 percent of children's visits, Dr. Kathleen E. Walsh and her colleagues write in the Journal of Clinical Oncology. They studied the records of 10,995 medications taken by cancer patients at three adult clinic and one pediatric oncology clinic in the Southeast, Southwest, Northeast, and Northwest, searching for errors in medications administered at the clinics or prescribed to be given at home. A previous study that looked at medications given only at a cancer center found a 3 percent error rate.

In the UMass study, there were 22 errors among 117 pediatric visits and 90 errors among 1,262 adult visits for an overall error rate of 8 percent. More than half of the 112 medication errors had the potential to cause harm and 15 did result in injury. Most of the errors involved the wrong doses, often because two sets of orders were written: one when the patient was diagnosed and another when adjustments were made on the day of treatment. Only five mistakes were caught before they reached the patient.

Many more medication mistakes were made at home for children than adults, the study found. Three-quarters of the pediatric errors, but only 7 percent of adult patient errors, were made at home. In one example of a home error, the mother of a child with leukemia being treated for an abscess gave the child an antibiotic twice a day at home instead of three times a day because she misunderstood the instructions.

Better communication could have prevented many of the errors, the authors conclude. Eliminating two sets of dosage orders would help in the clinic and educating parents would help with home doses, they suggest. They also note that the clinic that used complete electronic medical records and computerized order entry had the lowest rate of errors, with only one chemotherapy error in 500 patient visits.

"As cancer care continues to shift from the hospital to the outpatient setting, the complexity of outpatient cancer care is growing, with increasing opportunities for medication errors, particularly in the home setting," the authors write. "The findings of our study may help to reframe medication safety priorities for patients with cancer and suggest some practical targets for intervention to improve the care of both adults and children."