Techniques relate to handling outstanding cache miss prefetches. A processor pipeline recognizes that a prefetch cancelling instruction is being executed. In response to recognizing that the prefetch cancelling instruction is being executed, all outstanding prefetches are evaluated according to a criterion as set forth by the prefetch cancelling instruction in order to select qualified prefetches. In response to evaluating, a cache subsystem is communicated with to cause cancelling of the qualified prefetches that fit the criterion. In response to successful cancelling of the qualified prefetches, a local cache is prevented from being updated from the qualified prefetches.