There are two main types of lung cancer — small-cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) — and each type is further divided into subtypes.
Overall, symptoms of lung cancer don’t differ much based on type, but there may be occasional differences in when or how symptoms appear for the first time.
SCLC
SCLC is almost always linked to tobacco smoking.Based on what this cancer looks like under the microscope, SCLC is further divided into small-cell carcinoma (tumors made of small cancer cells) and combined small-cell carcinoma (tumors made of small cancer cells and non-small lung cancer cells).
Grouping these forms of cancer in this way helps scientists better distinguish the differences between them and help inform treatment strategies.
NSCLC
NSCLC makes up as many as 90 percent of all lung cancer cases. This type of cancer typically grows more slowly than SCLC and causes few or no symptoms until it has spread, so it tends to be diagnosed after it has already advanced.There are three main subtypes of NSCLC:
Adenocarcinoma
Large-cell undifferentiated carcinoma
Squamous cell lung cancer
Adenocarcinoma is the most common subtype of lung cancer in the United States, accounting for 45 percent of all cases. It’s also the cancer type that’s more prevalent in women than men.It develops more predominantly in nonsmokers, although smokers develop adenocarcinoma, too.
“The symptoms of adenocarcinoma and other types of lung cancer often overlap,” says Velez. She says adenocarcinoma tends to start in the outer parts of the lung, which may delay the onset of tell-tale coughing symptoms. “So, women may present later with symptoms related to metastatic spread rather than primary lung symptoms like cough and shortness of breath.”
Large-cell undifferentiated carcinoma makes up about 10 to 15 percent of all NSCLC lung cancer cases. It can start in any part of the lung and spreads faster than other NSCLC subtypes. It is strongly associated with cigarette smoking.
Squamous cell lung cancer tends to start in the center of the lung, next to the main airways, and is also associated with smoking. It tends to be more common in males than females.
