What is colorectal cancer?
Cancer occurs when cells in the body start to grow uncontrollably. Colorectal cancer is cancer that originates in the colon or rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they originate. Colon cancer and rectal cancer are often grouped together because they share many common characteristics.
Most colorectal cancers begin as a growth in the inner lining of the colon or rectum. These growths are referred to as polyps.
While some types of polyps may develop into cancer over time, typically over many years, not all polyps undergo this transformation. The likelihood of a polyp becoming cancerous depends on the type of polyp. The two main types of polyps are:
- Adenomatous polyps (adenomas): Occasionally, these polyps progress to cancer. As a result, adenomas are referred to as precancerous conditions.
- Inflammatory polyps and hyperplastic polyps: These polyps are more common, but are generally not precancerous.
Factors that can make a polyp more likely to contain cancer or raise the risk of colorectal cancer development include:
- If a polyp of more than one centimeter is found.
- If more than two polyps are found.
- If dysplasia, another precancerous condition, is found following the removal of a polyp. This implies the existence of an area within the polyp or the lining of the colon or rectum where cells appear abnormal, but not like true cancer cells.
To better understand colorectal cancer, it’s important to know its composition.
The colon and rectum make up the large intestine, which is part of the digestive system, also referred to as the gastrointestinal system.
Most of the large intestine is made up of the colon, which is a muscular tube approximately 1.5 meters long. Different parts of the colon are divided and have distinct names based on the direction food travels through them. Let’s begin with:
- Ascending colon: It begins with a pouch called the cecum, where undigested food arrives from the small intestine. It extends upward over the right side of the abdomen.
- Transverse colon: Extends across the body from the right side to the left side.
- Descending colon: It descends (heads downwards) on the left side.
- Sigmoid colon: Due to its «S» shape. The sigmoid colon is attached to the rectum, which connects to the anus.
The ascending and transverse parts of the colon together are referred to as the proximal colon.
The descending and sigmoid sections of the colon together are referred to as the distal colon.
Colorectal cancer in Mexico
Colorectal cancer (CRC) is a significant health concern in Mexico, ranking third in terms of incidence but first in mortality among all cancers, exceeding both prostate and breast cancer. According to the International Agency for Research on Cancer, a part of the World Health Organization (WHO), out of the 14,900 cases reported in 2018, approximately 48% of diagnosed patients died.
In Mexico, in 2017, there were 85,201 deaths attributed to colorectal cancer, with an estimated overall rate of 6,506 cases per 100,000 inhabitants (5.24%), affecting 10.7% of men and 5.5% of women.
The states with the highest death rate were Mexico City (7.24%), Nuevo Leon (6.71%), Baja California (6.26%), Baja California Sur (6.2%) and Chihuahua (6.2%). The mortality rate per 105 inhabitants and age group has increased in recent years. In 2017 in people 49 years old or younger it was 1.06% and in people 50 years old or older, 22.03%
Colorectal cancer in Latin America.
Globally, it is estimated that more than one million individuals are diagnosed with this condition annually, resulting in around 608,000 deaths. In Latin America it ranks fourth among the most frequently diagnosed cancers among men and third place among women. Despite this, it still does not seem to receive enough attention.
The incidence rate increase in Latin America is expected to continue unabated, primarily due to people’s standard of living (a more sedentary lifestyle and unhealthy eating habits). The aging population will also play a role in the increasing incidence rates, with over 100 million people aged 60 and overestimated to be living in Latin America and the Caribbean by the year 2020, further contributing to the emergence of more cases.
Multiple barriers exist that prevent the early diagnosis and timely treatment of colorectal cancer in Latin America, including the limited number of specialists and the continuing inadequacies in the healthcare system infrastructure. In many regions of Latin America, the current infrastructure frequently lacks the capacity to provide timely screening, chemotherapy, and surgery for all patients.
Colorectal cancer worldwide.
Colorectal cancer is a global condition, with an annual incidence of approximately 1,000,000 cases and a mortality rate of over 500,000.
The highest incidence rates of colorectal cancer are found in the United States, Western European countries, Australia, and New Zealand, with an average of 45 cases per 100,000 inhabitants. In contrast, in Asia and Africa, the annual rate is 10 cases per 100,000 inhabitants. On a global scale, it is the fourth most common type of cancer.
Screening guidelines involve administering a simple test to a healthy population to identify individuals who may have a condition but are not yet showing symptoms. Given that colorectal cancer has the potential to be detected early, emerging from benign precursor lesions, it becomes feasible for identification through screening programs targeting entire populations. While screening guidelines for colorectal cancer vary from country to country, the general recommendation is to commence screening in the average-risk population at the age of 50 and continue at regular intervals until the age of 75. Screening tests available for colorectal cancer include fecal occult blood testing, sigmoidoscopy, and colonoscopy.
Symptoms
Usually, symptoms appear in advanced stages, stressing the importance of remaining vigilant.
- Changes in bowel movements that last several days.
- Intermittent diarrhea.
- Constipation.
- Thinner stools.
- Rectal bleeding, dark stools, blood in feces, or on toilet paper.
- Abdominal cramps or pain.
- Fatigue and weakness.
- Persistent sensation of needing to have a bowel movement that doesn’t subside after doing so.
- Unexplained weight loss.
If you experience any of these symptoms persistently or for an extended period of time (months), avoid self-medicating and seek medical attention to determine the cause and appropriate treatment.
Colorectal cancer treatment.
Surgery: A procedure in which doctors remove cancerous tissue.
Chemotherapy: Special drugs are used to shrink or kill cancer cells. These medications can come in the form of oral tablets or injections administered into your veins, or in some cases, both methods may be used.
Radiation therapy: High-energy rays (similar to X-rays) are used to kill cancer cells.
Immunotherapy: Drugs are used to help a person’s immune system recognize and destroy cancer cells more effectively.