Introduction
Life expectancy in colorectal cancer is enormously variable and varies from person to person. The individual prognosis of the disease depends on the type of tumor, its exact location, early detection, time of therapy, response to therapy, the patient’s own immune system, personal general condition and several other factors. Even with exact knowledge of the individual risk factors and stages of the disease, doctors can only determine an approximate average life expectancy, which in individual cases can unexpectedly be exceeded or fallen short of again and again.
The general life expectancy for colorectal cancer is in the midfield compared to other cancers. Although colorectal cancer can be treated well, not all cases can be cured because the disease is often diagnosed too late, for example when the cancer is already growing outside the bowel. In most cases, colorectal cancer is referred to as “colorectal carcinoma”. This word itself contains the different localizations in the colon and rectum, which have different life expectancies. Without committing oneself to exact prognoses, life expectancies for the individual stages can be approximated in the following.
The different stages of colon cancer
Depending on the progression of the cancer, cancer stages can be classified in which the localization of the cancer in the intestinal wall is the most important factor. These stages are accompanied by different life expectancy. Life expectancy in stage I is very good.
In this stage of the disease, there is a malignant tumor in the intestine, but it is still small, localized and has only affected a few layers of the intestinal wall. The cancer is located in the mucosa of the inner intestinal wall. Below the mucosa there is a small intermediate layer and then the first muscle layer.
In stage I, the tumor has grown to the first muscle layer, the so-called “Muscularis propria”. There are no metastases in local lymph nodes or in distant organs at this stage. More than 95% of all patients survive the disease within the first 5 years after diagnosis.
Often no chemotherapy is necessary at this stage, as the cancer can be safely and widely removed during surgery. Stage II represents a slightly advanced variant of colon cancer. It is important to note that the cancer is still localized and in most cases there are no metastases in lymph nodes of the intestine or in other organs.
This means that the cancer can be removed easily and completely by surgery, often involving extensive removal of the affected intestinal segment. At this stage, however, the cancer has grown within the intestinal wall, sometimes infiltrating the muscle layers of the intestine and the fatty tissue around the intestine and may already spread to the peritoneum. Even if no litter has been diagnosed yet, it is possible that cells have already entered the peritoneal cavity and attacked the peritoneum.
Therefore, after surgical removal of the tumor, it must be decided individually whether subsequent chemotherapy is required. Chemotherapy can fight undetected cancer cells throughout the body and prevent microscopic, invisible metastases. Since the probability of small metastases and spread is increased in this cancer stage, life expectancy in the first 5 years is reduced to about 90%.
A distinction between colon carcinoma and rectal carcinoma is useful here, as the latter, also known as “rectal carcinoma”, has a worse prognosis. Due to the different blood supply in the intestine, metastases occur earlier in rectal carcinoma. In stage II, there is a probability of survival of about 85%.
Stage III is already a very advanced phase of colorectal cancer. The cancer in this stage is no longer in its early stages, but has already spread locally and to the adjacent lymph nodes. The special feature of this stage is that cancer cells have entered the lymph channels of the intestine and formed small metastases in surrounding lymph nodes.
For life expectancy it is also relevant whether only 1 lymph node or a large number of lymph nodes are affected. The latter indicates an advanced infiltration of the lymphatic system and reduces the probability of a complete cure for colorectal cancer. Also in this stage, rectal cancer is the more dangerous variant in contrast to colorectal cancer.
Life expectancy in stage III is still just under 60%.Therapeutically, chemotherapy following surgery is essential in this case, as there is a high probability that there are undetected cancer cells in the intestine and lymphatic system that cannot be eliminated surgically. Stage IV represents the final stage of colorectal cancer. It is characterized by the fact that the cancer is no longer restricted to the intestine or the surrounding lymph nodes, but has infiltrated distant organs and metastasized there.
Therapy must be made dependent on the patient’s state of health and the individual case. In many cases a cure can still be sought. For this purpose, all tumors in the intestine and the metastases must be removed in a major operation.
With a subsequent chemotherapy, further cancer cells in the body can be combated. However, the probability of a cure is not particularly high. In very advanced cases with a poor general state of health, the therapy can be palliative. This is a palliative therapy whose aim is no longer to cure. The life expectancy of all stage IV diseases is over 5%.