Worried my 20 year old sister may have cancer as a shadow was found near her liver

Hi, so I know it's probably not cancer but bear with me. My sister is 20 years old and has always been a curvy lass. The past 8 months she's started to being sick 3 or 4 times a week mainly on a morning (and no it's not pregnancy she's had numerous tests). She's also suffering from extremely low mood and has gone from a 12/14 to a size 8, She had an ultrasound almost 4 weeks ago and she overheard the radiologist mention a shadow when scanning near her liver and surrounding areas. We were told ,7 to ,10 days for results but still here waiting. She's also had a sigmoid colonoscopy which showed many polyps... She has to go back later this month for a full colonoscopy. 

Basically she's 20, lost weight dramatically, she hear there's a shadow Nd then the polyps. I know she might be too young for cancer but I am petrified as her brother. We've lost lots of family through canver, I wouldn't be able to cope if my sister had it... I also know it's not about me but I am petrified with worry, I don't even know of this is relevant for this forum but I needed to express my worry because my sister's is deffo NOT the talking type. 

Thank you on advance and I'm sorry If this post is not suitable I'm just worried that's all 

Thank you on advance and I wish everyone of you the best xx