Chemotherapy and hair extensions?

Hello,Im 18,and I was just wondering if it is safe to get hair extensions after chemotherapy. It has been about 4 months and my hair is about 4 inches or longer, they are all different lengths. Because i heard that in some cases the extensions are too heavy for the hair and makes it weak and the root breaks off? Is that true?And also will the extensions be overall damaging, short term and long term effects?