Most common type of carcinoma lung is-
**Core Concept**
Lung cancer can be broadly classified into two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). NSCLC accounts for approximately 85% of all lung cancer cases, making it the most common type.
**Why the Correct Answer is Right**
NSCLC includes several subtypes, such as adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Adenocarcinoma is the most common subtype, accounting for about 40% of NSCLC cases. This type of cancer originates in the glandular cells, which are located in the outer part of the lungs. The exact cause of adenocarcinoma is still not fully understood, but it is often linked to smoking and exposure to secondhand smoke.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a recognized subtype of lung cancer.
**Option B:** This option is incorrect because it is a rare type of lung cancer, not the most common type.
**Option C:** This option is incorrect because it is a type of cancer that affects the brain, not the lungs.
**Clinical Pearl / High-Yield Fact**
The American Cancer Society recommends that individuals who smoke or have a history of smoking should undergo annual low-dose computed tomography (LDCT) scans to screen for lung cancer, especially if they have a 30-pack-year smoking history.
**Correct Answer: A. Adenocarcinoma**