The stage of a cancer states the extent of spread within the body. Stage of the cancer is the most important factor in determination of treatment and estimation of expected success of the treatment. When determining the tumor stage in colorectal cancers;
Up to which part of the intestinal wall has the cancer grew,
Did it spread to adjacent tissue and organs?
Did it spread to surrounding lymph nodes or distant organs?
Staging of a colorectal cancer is determined based on the physical examination findings, biopsy results and imaging techniques such as CT, MRI and PET.
When staging is performed depending on examination, biopsy and imaging techniques, this is called clinical stage,
When stage is determined by combining the investigation results of biopsy samples, it is called pathological stage.
Sometimes surgeon may encounter a more advanced stage disease that could not be detected during imaging. Therefore, pathological stage may be more advanced than clinical stage.
As most of the patients with colorectal cancer undergo surgery, cancer stage is generally determined by pathological examinations and this means a more accurate staging.
How is the Colorectal Cancer Stage Defined ?
Generally a system called TNM is used for colorectal cancer evaluation. TNM system contains information under 3 main titles.
In which layers of the intestinal wall is there a tumor involvement and is it spread to adjacent organs?
Is there a tumor involvement in surrounding lymph nodes (N)? Lymph nodes are pea like glands that are consisted of immune system cells and they are generally the first step of cancer spread.
Did the cancer metastasize (M) to other organs? Although colorectal cancers can spread anywhere, their most frequent distant organ metastasis is to liver and lungs.
In this staging system, the number following the T, N and M letters provide more detailed information. Increasing numbers mean more advanced stage cancer. After all this information is obtained and represented in letters and number, cancer stage is determined.