My mother has paranasal sinus cancer. should i be worried for what this means?

Sure, but wait: Sinuses are mysteries to people but they are hollow cavities that add to voice quality, but when inflamed, can cause bleeding, drainage, infectiojn, and unusually cancer:frontal, ethmoid, spenoid and maxillary describe locations. The neighboring things are sensitive and important: brain, eyes, ability to smell and taste. Some can be cured, other can be relieved. But it isn't simple. See ent/radonc.