Hi Morris ime sorry about your mum .my partner died 18 months ago . She had cancer of unknown primary meaning althoe like your mum its so small a few cells they cant actualy detect it or it may not be there anymore .its i realy sneaky diseas it travels round your body and litraly hides then it can suddenly become agresive and grow at a fantastic rate .liz my partner ended up with two types . Liver and lung . In my oppinion now i think they should say yes your clear then say but !!!  They said liz was incurable but treatable and she was gone in six weeks .thing is in life when somthing happens the first thing we think is who's fault is it i think we are still in the dark ages with this disease .we se on the media people who are cured etc etc but it never shows you the othere side so we are not prepared . If your in doupt you need to spk to an independant body .every hospital has patient liasion called palls if you think there was and error contact them they will investigat and tell you what to do they may make a apointment to spk to the oncology team etc . I think you need your mint putting to rest . Hope thats helped but ime just like you ime not medicaly trained but i felt like you plus i had studied and studied i can even tell you how a pet and ct scanner works .best wishs paul