I think "phrase" implies a cadence. But cadences can take myriad forms. The one thing they have in common is the "fall", something that shows that something has come to an end. BUT don't take this to mean "THE END", the final cadence. The final cadence will be more "final" than any that preceded it. Classical music describes only the half cadence and the full cadence. But there are many forms a cadence can take --- music written outside the tonal system still needs to create the feeling of --- oh, call it "a breath", inhale-exhale. Listen to some Stockhausen, or late Stravinsky ("Agon") --- do you feel any cadence moments? I think you will.