my mom has positive malignant cells on her biopsy

Hi! I am Ruby and yesterday we found out the result of my mom's biopsy of her breast lump. It is positive in malignant cells. We are shocked, devastated and saddened. We are 8 in the family and my mom is our rock. We don't know what to do next. She has a 3day trip and when she is back we don't know what to do. We will always be here to support her. A sister of mine talk to her doctor yesterday without my mom brcause she was on a trip, the doctor said he recommend to remove the lump. But I am worried about it because he did not tell my sister if mom still needs more test to know what type of cancer it is. My mom's doctor is a surgeon so he said he will do a surgical operation. But we would like to request more test to know what type of cancer it is. If it spread or not.. do my mom need to see an oncologist?.. please help, my mom lives in Asia not in US.