If the results are confirmed, it could change the standard of care for the worst of cancers. It would also represent an advance for the field of individualized medicine, which seeks to craft treatment plans for each patient.

A total of 83 patients were treated. Of those, 73 received matched therapy, usually with targeted drugs specifically developed for certain genetic abnormalities. The rest didn’t get any matched therapy, but received other treatments.

Of patients given drugs that matched more than half of tumor mutations, half responded. Of the remaining whose tumors were less well matched or totally unmatched, just 22 percent responded.

Those whose tumors shrank, or in whom the disease stabilized for at least six months, were considered to be responders. A total of 28 patients got highly matched therapy, the remaining 55 received lower-matching therapy or were totally unmatched.