It's a lot harder for a machine to match the best oncologists in cancer treatment than it was to beat human competitors on "Jeopardy." It's still a worthy goal. The problem is that so far the artificial intelligence platform called Watson hasn't matched the hype generated by IBM's over-the-top advertising campaign.

Earlier this month, the medical website STAT reported that internal documents from IBM Corp. revealed the computing system had recommended "unsafe and incorrect" cancer treatments. The system is being used in conjunction with human medical judgment, and there are no reports of patients being harmed. But in the documents obtained by STAT, doctors who had tried to use Watson to help them design treatment complained that the system wasn't ready to practice medicine.

The machine learning revolution is coming to hospitals with or without Watson, especially because cancer is a data problem. Cancer cells are just a patient's cells with coding errors. Each case of cancer is unique, and will respond best to different treatments depending on the patient's own DNA and the errors in the cancer cells.