There are a lot of ifs in your question and will be in this answer. The tumor in the chest is most likely to develop symptoms first because the chest cavity is smaller than the abdominal region. It could pose more serious problems if it grew to block lung or breathing passages or the heart, liver, or pancreas areas. This would be more immediately serious. A tumor in the abdomin could be serious as it would block stomach, kidney, and intestinal passages.
