Which form of lung cancer is associated with the poorest prognosis?

• A. Squamous cell.
• B. Adenocarcinoma.
• C. Large cell.
• D. Small cell.

Answer: (D)

In lung cancer, prognosis varies by histology; small cell lung cancer has the poorest prognosis due to its aggressive biology. It grows rapidly and tends to metastasize early, so many cases are already advanced at diagnosis and surgical cures are rare. Although it may respond to chemotherapy and radiation initially, relapses are common and overall survival, especially in extensive disease, remains very limited. The other main types—squamous cell, adenocarcinoma, and large cell—can have better outcomes when detected early and treated definitively, though prognosis still depends heavily on the stage at diagnosis. Small cell lung cancer is also strongly associated with smoking.