The exact months when pancreatic head cancer starts to be serious cannot be generalized. Pancreatic head cancer has a high degree of malignancy and is affected by multiple factors, including the degree of malignancy, treatment and patient’s condition. Overall speaking, pancreatic malignant tumor will worsen in about 2 to 3 months and endanger patients’ life if there is no timely treatment. 1. Malignant degree: if the cancer cells grow faster, the tumor is more malignant and progresses more rapidly, and it can develop to advanced stage in several months; if the tumor is less malignant and does not invade blood vessels, the lesion progresses more slowly, and the time may be relatively longer. 2. Treatment: if the standardized treatment measures are not taken in time, or some cancer cells are not sensitive to treatment, it takes shorter time for pancreatic head cancer to develop into advanced stage; if pancreatic head cancer undergoes radical surgery at early stage, and is treated with chemotherapy, targeting and immunotherapy at later stage, the cancer develops relatively slowly and positive results can be obtained. 3. Patient’s own situation: if the patient’s physical quality is good and resistance is strong, the prognosis is relatively optimistic; if the patient has more complications, hypertension, diabetes and other basic diseases, or if the patient is older, the prognosis is relatively poor. If diagnosed with pancreatic cancer, patients should keep a good mindset and actively cooperate with doctors for standardized treatment, which can improve the prognosis to a certain extent.