Blood values in colorectal cancer
Colon cancer is a disease that cannot be detected per se in the blood. There are some unspecific blood values that could be altered. For example, the unspecific inflammation value CRP or the laboratory value that stands for cell decay, the lactate dehydrogenase LDH. In the case of chronic bleeding from the tumour, signs of anaemia could be detectable (anemia of chronic disease): drop in haemoglobin, reduced erythrocyte count and iron values. Tumour markers can be measured to monitor whether the cancer is regressing or recurring, especially the CEA (carcino-embryonic antigen).
Forecast
The prognosis of colorectal cancer depends strongly on the tumor stage. In stage I (according to UICC) the 5-year survival rate is about 95%, in stage II up to 90%, in stage III up to 65% and in stage IV about 5%. In principle, every cancer is not curable, but treatable, with sometimes more and sometimes less success.
Colorectal cancer is one of the types of cancer that can be treated very well in its early stages, so that no spread (metastasis) or recurrence of the cancer (relapse) is to be expected. Even then, one should not speak of a cure, but correctly speak of a “very good prognosis”. A prognosis is a doctor’s prediction about the further course of the disease.
It always involves empirical estimates and statistical probabilities. For assessment purposes, the cancer in question is assigned to the defined TNM stages. This involves examining how far the tumour has grown (T), whether lymph nodes are affected (N) and whether it has spread (M).
In general, the fewer affected lymph nodes and scattered tumours are present, the better the prognosis. The size of the tumour is actually rather unimportant, more important are the layers of the intestine that it has penetrated. Therefore, the complete surgical removal of the tumor is of the greatest importance among the therapy options.
Radiation and chemotherapy are also important treatment measures. For example, in the case of a smaller tumour that has not affected or otherwise spread to the lymph nodes, which has spread to the muscle layer of the intestine (T2), the 5-year survival rate is over 90% (stage I). From the time when more than two stray tumours are located in organs other than the intestine, the probability of survival is less than 5%, regardless of the size of the tumour or the number of lymph nodes affected. Between this “best” and “worst case” the prognosis ranges depending on the exact diagnosis. After the initial treatment of colorectal cancer, follow-up care is of particular importance because, like general screening, it attempts to detect tumors in small and thus operable stages.
