Why are malignant tumors a major concern in medicine?

Malignant tumors are a major concern in medicine primarily because they have the ability to spread and invade vital organs. This characteristic distinguishes malignant tumors from benign tumors, which do not metastasize or invade surrounding tissues. When malignant tumors metastasize, they can travel through the bloodstream or lymphatic system to distant sites in the body, establishing new tumor growths that can disrupt the function of essential organs. This spread can lead to severe complications, making treatment more challenging and often resulting in poorer prognoses for patients. The aggressive nature of malignant tumors, combined with their potential to affect multiple organ systems, underscores their significance in medical concerns and the ongoing need for effective treatment strategies and research.