My mom had a stone in her gal bladder and doctors operated and removed the stone and gal bladder. what chances are cancer spreading to liver also?

Maybe none: Gallstones are very frequent, but they are benign (no cancer), therefore most likely, removal of gallbladder and stone is curative. Gallbladder carcinoma is associated with gallstones, but very rare. Check the pathology report to see if cancer was detected or not. Spreading to the liver depends on how advanced (deeply invasive) it was at the time of detection.

Unclear question: A gallstone is not cancerous. Was there cancer in the gallbladder? Please restate your question.