Colon cancer is one of the most common malignant tumors in mainstream society. Recently, evidence has been collected that differentiates this entity according to its place of appearance.
Cancer is the second leading cause of death worldwide, second only to heart disease and other heart problems in high-income countries. The podium is occupied by lung and bronchus cancers, prostate cancer, colon and rectal cancer, melanoma and others. Tobacco alone is the cause of 22% of cancer deaths, thus being considered the main risk factor for developing this type of neoplasm.
The malignant tumor that concerns us here is the one that grows in the colon, the last portion of the digestive system, whose main function is to extract water and salt from the solid waste present in the feces before they are eliminated from the body. According to various sources, in countries such as the United States this is the third most diagnosed type of cancer, since it is only surpassed by lung cancer (and its variants) and prostate cancer.
However, the detection of a malignant tumor in the colon is not the end of the road. As indicated by the American Cancer Society, the overall survival rate of all stages of this type of neoplasm is 63%, with a chance of recovery of up to 91% if the tumor is localized.
Beyond all these data, for some years several differences between left and right colon cancer have been explored, because, although they affect the same portion of the digestive tract, their symptoms, prevalence and prognosis are relatively different. Here’s everything you need to know about this topic.
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What is colon cancer?
Let’s start with the basics. “Cancer” is the name given to a series of related diseases, whose common characteristic is that, in all of them, some of the cells of the body begin to divide without stopping and spread to adjacent tissues. Not all cancers manifest with tumor masses (such as leukemia), but most of them generate localized tumors that end up spreading without adequate treatment.
A normal cell has a programmed cell cycle, that is, it grows, divides, and dies as the body needs them. When a mutated cell line arises, it will reproduce uncontrollably and will not respond to typical senescence patterns, thus generating an agglutination of cells known as “primary tumor”.
From here, all exposed language is more or less known to the general population. When mutant cells expand from the primary tumor to other areas of the body, the dreaded process known as metastasis occurs, in which tumors of the same cell lineage can develop in other areas of the body (secondary tumors).
In the case that concerns us here, the primary tumor appears as a result of uncontrolled cell multiplication in the tissues of the colon and / or rectum. These can originate in each of the 3 tissue layers of the portion of the digestive system: mucosa, muscular and serosa. It should be noted that more than 90% of colorectal cancers are adenocarcinomas, that is, they have their origin in cells that constitute the inner lining of the glands of external secretion.
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What are the differences between right and left colon cancer?
Althoughmalignant tumors of the left and right colon are located in the last portion of the digestive system, they are beginning to be treated almost as two different clinical entities, as they differ in prevalence, symptomatology, prognosis and treatment. Here are the 4 differences between right and left colon cancer in a cursory way.
1. Different prevalences
Prevalence is defined as the number of individuals within a population who exhibit a particular characteristic or event, in this case, malignant tumor growth in the colon. Spanish studies have detected that70% of tumors in the colon are located on the left side, while only 30% originate on the right. These results may seem clear and revealing, but, if we dig a little deeper, we will discover that this trend is not entirely clear.
For example, in the scientific publication “Location and clinical associated with colon cancer. Hospital Nacional Arzobispo Loayza (Peru)” has demonstrated a clear predominance of neoplasms on the right side, with a prevalence of 61.9% compared to 33.3%. These data are completely contradictory, so we cannot say that one is presented more than the other in all cases. What is clear is that, whatever its location, the pathology arises with different prevalences.
2. Different symptoms
Although the dominance of one type of cancer over the other does not seem to be entirely clear, it has been shown that the symptoms presented are different according to the location of the tumor in multiple medical information sources.
For example, it appears thatleft colon cancer shows rectorrhagia from its earliest stages. Thus, patients with this type of neoplasm will present stools accompanied by fresh red blood, indicating that the bleeding tissue is beyond the stomach (otherwise, the blood would be partially digested, which gives the blood a blackish color).
In addition to this, patients with left colon cancer seem to show colic abdominal pain before, that is, very intense and variable punctures over time that indicate the presence of an abnormality in their body. On the other hand, people with right colon cancer do not suffer these symptoms until the tumor is much more advanced.
On the other hand, as indicated by sources already cited, the most prevalent symptom of advanced right colon cancer is severe abdominal pain and anemia (with 76.9% of patients analyzed), while up to 57% of patients with left colon cancer manifest the presence of blood in the feces. Due to the anemia that characterizes neoplasm on the right side, it is estimated that the chances in these patients of suffering from asthenia (weakness and general fatigue) is up to 13 times higher than people with cancer in the left colon. Based on these results, we could conclude that right colon cancer is somewhat “quieter” and manifests itself more diffusely.
3. A different prognosis
Based on the above, it is easy to suspect thatthe overall prognosis of patients with right colon cancer will be much worse. As indicated by various medical sources, it seems that patients with this type of neoplasm have a worse prognosis, regardless of whether it is located in a specific area or has already metastasized.
4. Differences in who is at risk
Among people at higher risk (who are those with right colon cancer), it has been observed that patients tended to have slightly advanced age, a high body mass index (BMI), and regularly consume nonsteroidal anti-inflammatory drugs. In addition, it seems thatwomen are more likely to suffer from right colon cancer than men.
Final considerations
Although we would like to be able to tell you that these facts are clear and indisputable, the reality is very different. We have told you that right colon cancer seems to have a worse prognosis than left colon cancer, but it is only necessary to investigate other different sources to find appointments by professional doctors such as the following: “right colon cancer has some particularities that, normally, usually translate intoa better prognosis when it is detected without lymph node involvement”.
Does this mean that the data presented here are lies? Far from it. Each study collects figures and observes statistical trends, but these do not have to be applicable to all regions of the world and to all medical centers indistinctly. Many factors can play essential roles in the development and prognosis of a tumor and, for that reason, it is so difficult to address this set of diseases in many cases in a homogeneous and unequivocal way.
Therefore, as long as the aforementioned data are not standardized at the clinical level and both entities are completely split, we will continue to consider colon cancer as a similar pathological group. Of course, all sources agree on one fact: colon cancer on the right side manifests itself with more nonspecific symptoms, while thepresence of blood in the stool is usually much more typical in the left malignant tumor.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.
