Adenocarcinoma is a type of colon cancer that arises from glandular cells. It is the most common form of colon cancer, accounting for 95-98% of colon tumors. Adenocarcinoma can be diagnosed with a biopsy or other tests, which are used to determine the size and location of the tumor, and whether it has spread to nearby tissue. These results help doctors plan your treatment.
A doctor can use imaging tests to look for signs of adenocarcinoma, such as computed tomography (CT) scans or magnetic resonance imaging (MRI). These tests can create detailed pictures of your internal organs, and show whether there is cancer in one of them. They can also help doctors find out how far the cancer has grown, which is called its stage.
During a biopsy, your doctor removes a small piece of the tissue where you have cancer. Then a pathologist, or medical scientist, looks at it under a microscope to see whether there are any cancer cells and how many there are. The biopsy can help diagnose adenocarcinoma and other types of cancer, but it isn’t always accurate.
Once your doctor has the results of the biopsy, they may use a computer to estimate how fast your cancer is growing and what its stage is. This information is important because it helps them decide what treatments are best for you.
The stage of adenocarcinoma depends on how deep the cancer has grown into the wall of your colon and how much it has spread. It is often reported in stages, with stage 1 describing a tumour that hasn’t spread deeply into the tissues or to nearby lymph nodes. Stages 2 and 3 describe more advanced stages of adenocarcinoma where it has grown deeper into the tissues or spread to other parts of the body.
Invasive adenocarcinoma can be divided into four grades by a pathologist, with well-differentiated adenocarcinomas being more likely to grow slowly and not spread. Undifferentiated adenocarcinomas grow faster and are more likely to spread.
Our study included cases from a large, prospectively enrolled lung cancer cohort, the Harvard-Massachusetts General Hospital Lung Cancer Susceptibility Study. Invasive adenocarcinoma was defined according to the definition of histology used in this cohort, and adenocarcinoma with lepidic features were grouped together. Histology and region of invasive adenocarcinoma were analysed in cross-sectional models along with age, sex, pack years, and either tumor region or tumor lobe.
We found that regional distribution of invasive adenocarcinoma was not associated with either lobar distribution or histology, even when adjusted for age, sex, pack years, stage, and either tumor region or tumor lobe. This suggests that there are other factors that influence adenocarcinoma development that have not been identified in previous studies of this cohort. These other factors could be associated with airflow obstruction and therefore influence the risk of adenocarcinoma. Future research is needed to identify these factors.
