Last year, cancer researchers were astounded when studies presented at the annual meeting of the American Society of Clinical Oncology (ASCO) showed that IBM’s famous AI supercomputer, Watson, was capable of creating effective treatment regimens for cancer patients. But internal documents from the company include criticism from medical experts who say the system is recommending therapies that are “unsafe and incorrect,” Stat News reports.

According to Stat, the documents included in presentations made in June and July 2017 strongly criticized the Watson for Oncology system, a cognitive computing system trained by doctors to help choose the most effective cancer therapies for certain patients. At its harshest, the report stated that the “often inaccurate” suggestions made by the computer brought up “serious questions about the process for building content and the underlying technology.”

What is meant by “often inaccurate?” In one example, a 65-year-old man diagnosed with lung cancer and severe bleeding reportedly had a drug recommended to him that can lead to severe or fatal hemorrhaging. Although a spokesperson from Memorial Sloan Kettering Cancer Center (MSKCC)—which partnered with IBM in 2012 to train Watson to “think” more like a doctor—suggested this recommendation might have been part of system testing, this scenario raises concerns for the more than 230 hospitals around the world that have been using the system over the past few years to help diagnose and treat 13 different cancers in their patients.

In its defense, IBM says the computer program may not be entirely to blame. Instead, the documents pin the errors on the training provided by IBM engineers and doctors at Memorial Sloan Kettering Cancer Center. The report states that doctors apparently fed the system hypothetical data—meaning that Watson for Oncology could have been guided by doctors’ treatment preferences rather than actual patient data. 

Since these documents were brought to light by IBM itself, it seems the company is aiming for transparency no matter the cost. For their part, MSKCC representatives had this to say: “While Watson for Oncology provides safe treatment options, treatment decisions require the involvement and clinical judgment of the treating physician.” They added, “No technology can replace a doctor and his or her knowledge about their individual patient.”