Doctors are responsible for a minority of medical mistakes in radiation therapy

The New York Times recently featured a disturbing expose of serious medical errors associated with the newest forms of high tech radiation treatment, entitled, Radiation Offers New Cures, and Ways to Do Harm. The piece is an example of excellent medical journalism, compelling stories of two individuals who sustained truly horrifying injuries as the result of treatment errors framed a detailed investigation of similar errors that have occurred in New York State.

One of the most notable features of the medical errors highlighted by the article received only short shrift, however. That is unfortunate because it is an increasing source of medical error and is rarely included in public discussion of medical errors. Of the 1264 specific mistakes identified in the article, only a small proportion were made by doctors. The vast majority of errors were made by other people: physicists and programmers who ran the machines, ancillary medical professionals who positioned the patients during actual treatment, and support staff who brought the wrong patients for treatment.

Medical errors are a very serious problem and we should be engaged in an all out effort to reduce them to zero if possible. When people think about medical errors, they tend to imagine them as physician errors that could be corrected by greater diligence. Yet many medical errors are cause by people other than doctors, including people who are not medical professionals. These errors fall into three broad categories: errors introduced by complex monitoring and treatment machinery, errors caused by ancillary medical personnel, and clerical errors.

Consider the errors attributable to machinery. Extraordinarily complex machinery is involved in many aspects of medical care. In this case, the injuries and deaths were caused by a highly specialized and sophisticated form of radiation delivery, a linear accelerator with a multi-leaf collimator. The article explains:

… [A] linear accelerator with 120 computer-controlled metal leaves, called a multileaf collimator, … could more precisely shape and modulate the radiation beam. This treatment is called Intensity Modulated Radiation Therapy, or I.M.R.T. The unit St. Vincent’s had was made by Varian Medical Systems, a leading supplier of radiation equipment.

“The technique is so precise, we can treat areas that would have been considered much too risky before I.M.R.T., too close to important critical structures,” Dr. Anthony M. Berson, St. Vincent’s chief radiation oncologist, said in a 2001 news release.

Sophisticated machinery is run by computers and computers must be programmed. The case of Scott Jerome-Parks who was severely injured by excess radiation and subsequently died illustrates how serious errors can be made:

Tasked with carrying out [the treatment] plan was Nina Kalach, a medical physicist. In the world of radiotherapy, medical physicists play a vital role in patient safety — checking the calibration of machines, ensuring that the computer delivers the correct dose to the proper location, as well as assuming other safety tasks…

On the morning of March 14, Ms. Kalach revised Mr. Jerome-Parks’s treatment plan using Varian software. Then, with the patient waiting in the wings, a problem arose, state records show.

Shortly after 11 a.m., as Ms. Kalach was trying to save her work, the computer began seizing up, displaying an error message. The hospital would later say that similar system crashes “are not uncommon with the Varian software, and these issues have been communicated to Varian on numerous occasions.”

An error message asked Ms. Kalach if she wanted to save her changes before the program aborted. She answered yes.

Ms. Kalach did not know that the computer had not saved the treatment instructions that she had programmed. As a result, Mr. Jerome-Parks received a massive overdose of radiation:

The investigation into what happened to Mr. Jerome-Parks quickly turned to the Varian software that powered the linear accelerator…

When the computer kept crashing, Ms. Kalach, the medical physicist, did not realize that her instructions for the collimator had not been saved, state records show. She proceeded as though the problem had been fixed.

“We were just stunned that a company could make technology that could administer that amount of radiation — that extreme amount of radiation — without some fail-safe mechanism,” said Ms. Weir-Bryan, Ms. Jerome-Parks’s friend from Toronto. “It’s always something we keep harkening back to: How could this happen? What accountability do these companies have to create something safe?”

The software malfunction was one among many similar highly technical errors. Indeed more than half of the identified medical errors were related to programming the linear accelerator. Yet at the other end of the spectrum of sophistication, there were disturbingly large numbers of errors as well. In 174 instances, the wrong location was treated or even the wrong patient was treated. In 66 instances, staffing shortages or miscommunications resulted in treatment errors.

In total, at least 621 patients were harmed by medical errors, but ultimately only 6% of the errors were attributable to the physicians caring for the patients. The New York Times article on radiation treatment errors sounds an alarm not merely about a specific, highly technical form of treatment. It also raises serious questions about errors caused by ancillary medical personnel and even support staff. Such errors are inexcusable, and will require a different approach than conventional medical errors, an approach we must start working on immediately.

Amy Tuteur is an obstetrician-gynecologist who blogs at The Skeptical OB.

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