Diagnosis: model beats doctor
22.04.2013 - Computers are better than doctors at predicting the outcomes and responses of lung cancer patients to treatment, say Dutch researchers.
The team around Cary Oberije presented its findings at the 2nd Forum of the European Society for Radiotherapy and Oncology (ESTRO) in Geneva. They said the model’s predictions remained superior to those of doctors even after the latter had seen the patient. The models use genomic information from previous patients to create a statistical formula that can be used to predict the probability of outcome and responses to treatment using radiotherapy with or without chemotherapy for future patients.
Having obtained predictions from the mathematical models, the researchers asked experienced radiation oncologists to predict the likelihood of lung cancer patients surviving for two years, or suffering from shortness of breath (dyspnea) and difficulty swallowing (dysphagia) at two points in time: 1) after they had seen the patient for the first time, and 2) after the treatment plan was made. At the first time point, the doctors predicted two-year survival for 121 patients, dyspnea for 139 and dysphagia for 146 patients. At the second time point, predictions were only available for 35, 39 and 41 patients respectively.
For all three predictions and at both time points, the mathematical models substantially outperformed the doctors' predictions, with the doctors' predictions being little better than those expected by chance.The researchers plotted the results on a special graph  on which the area below the plotted line is used for measuring the accuracy of predictions; 1 represents a perfect prediction, while 0.5 represents predictions that were right in 50% of cases, i.e. the same as chance. They found that the model predictions at the first time point were 0.71 for two-year survival, 0.76 for dyspnea and 0.72 for dysphagia. In contrast, the doctors' predictions were 0.56, 0.59 and 0.52 respectively.
"The number of treatment options available for lung cancer patients are increasing, as well as the amount of information available to the individual patient. It is evident that this will complicate the task of the doctor in the future," said Dr. Oberije from Maastricht University Medical Center. "If models based on patient, tumour and treatment characteristics already out-perform the doctors, then it is unethical to make treatment decisions based solely on the doctors' opinions. We believe models should be implemented in clinical practice to guide decisions."