Britannica Sources used in this answer

Why is lung cancer often diagnosed at a late stage?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Health monitoring — human disease The routine monitoring of blood pressure levels is an important part of assessing an individual's health. Blood pressure provides information about the amount of blood in circulation and about heart function and thus is an important indicator of disease.

Lung cancer is frequently diagnosed at a late stage primarily because symptoms typically do not manifest until the disease has reached an advanced state or has spread to other parts of the body.12

In the early stages, the disease often produces no noticeable signs, or the symptoms that do occur are variable and nonspecific, making them difficult to distinguish from other conditions. For example, a small tumor that does not obstruct an airway may not cause any shortness of breath, which is a common indicator of respiratory issues. Because of this lack of clear, early warning signs, many cases are discovered only after the cancer has metastasized.32

Furthermore, some aggressive forms of the disease, such as small-cell lung cancer, tend to spread rapidly before any symptoms become apparent to the patient. Consequently, most individuals are diagnosed well after the tumor has originated, which contributes to the disease's generally poorer prognosis compared to many other types of cancer.2