A 3cm malignant tumor is considered large overall. The severity of a tumor depends on where it grows, but also on its own malignancy. A 3cm malignant tumor is considered larger overall, and the size should also be measured with reference to the location of the tumor growth. In addition to considering the size of the tumor, it is also important to focus on whether the tumor has invaded important organs and tissues. For example, some tumors are still relatively small, but obviously invade the surrounding large blood vessels leading to surgical difficulties, which is more serious. Some tumors are a little bit bigger, but more shallow and limited, which is not as serious as the former. Therefore, the tumor itself should not focus on the size alone, but should be judged by overall assessment. If the malignant tumor is 3cm large, you must seek medical treatment in time, and actively use the correct therapy under the guidance of the doctor, so as not to miss the best time for treatment.