Adenocarcinoma

Adenocarcinoma counts 40% of all lung cancer cases. Unlike small cell lung cancer and squamous cell lung cancer, which both tend to be more centrally located, adenocarcinoma usually is seen in peripheral lung tissue.  The peripheral location of adenocarcinoma in the lungs is due to the use of filters in cigarettes which prevent the larger particles from entering the lung. Generally, adenocarcinomas grow more slowly and form smaller masses than the other subtypes. However, they tend to form metastases widely at an early stage.

Adenocarcinoma also the most common type of lung cancer in women and non-smokers and in people under age 45, however, the incidence of adenocarcinoma has increased in the last two decades and it is now the most common histological subtype in both men and women. A subtype of adenocarcinoma, the bronchioloalveolar carcinoma, is more common in female never-smokers, and may have different responses to the lung cancer treatment option.

Adenocarcinoma accounts for about 30% of primary lung tumors in male smokers and 40% in female smokers. Among non-smokers, these percentages approach 60 percent in males and 80 percent in females. This disease also is more common among Asian populations. The reason for the increasing incidence of adenocarcinoma is not well understood, but may be related to changing patterns of smoking. Adenocarcinomas tend to be peripherally located, smaller and vary histologically from well-differentiated tumours to solid masses with occasional mucin-producing glands and cells.

Some studies indicate that 60 to 70% of patients with lung adenocarcinoma have cancer spread to other parts of the body at the time of diagnosis.

Overall, less than 10 percent of people with primary lung cancer survive five years after diagnosis. However, five-year survival rates can be as high as 35 to 40 percent for those who have localized lung cancer removed in its early stages. These five-year survival rates approach 85 percent for patients under age 30.

Main Article: Non-small Cell Lung Cancer