Final answer:
The first signs of symptoms for cancer can be caused by the mass of a primary tumor or its ulceration. These signs are not definitive of cancer, but they should lead to a doctor's visit.
Step-by-step explanation:
The first signs of symptoms for cancer can vary depending on the type of cancer. In general, the early warning signs of cancer are usually caused by the mass of a primary tumor or its ulceration. For example, a tumor in the breast might produce a detectable lump, while a tumor in the lung might cause a persistent cough and difficulty breathing. These signs are not diagnostic of cancer, but they should prompt a visit to the doctor to rule out any serious conditions.