Of 53,801 patients, 67% had right-sided colon cancer. Patients with right-sided cancer were more likely to be older, to be women, to be diagnosed with a more advanced stage, and to have more poorly differentiated tumors.
Right-sided colon cancers are more unusual
Right-sided polyps are more likely to develop into cancers — which often grow rapidly and have a higher risk for metastasis, spreading to distant body areas.
The mean age for the onset of the disease is 16 years, but can occur early at 8 years of age. The number and size of polyps increase with time. Most of the CRC (about 70%) tend to occur in the left side, whereas, a small percentage (about 10%) occurs in the right side [38, 39].
The sigmoid colon is the most common site for cancer of the colon. Rectal carcinoma is the most common cancer of the lower gastrointestinal tract. One of the determining factors for preservation of the anus is how close the tumor is to the sphincter.
Colon cancer most often spreads to the liver, but it can also spread to other places like the lungs, brain, peritoneum (the lining of the abdominal cavity), or to distant lymph nodes. In most cases surgery is unlikely to cure these cancers.
Metastatic Colorectal Cancer May Spread Early in the Disease, Study Finds. Colorectal cancer cells can break away from the original tumor and travel through the blood or lymph system to other parts of the body, including the liver, lungs, and brain.
This analysis provides evidence that the prognosis of localized left-sided colon cancer is better compared to right-sided colon cancer. Also, the patients with right colon cancer have more advanced stage, mucinous tumor and are older.
Cancers arising from the left side of the colon generally cause bleeding, or in their late stages may cause constipation, abdominal pain, and obstructive symptoms. On the other hand, right-sided colon lesions may produce vague abdominal aching, but are unlikely to present with obstruction or altered bowel habit.
Colon cancer, or cancer that begins in the lower part of the digestive tract, usually forms from a collection of benign (noncancerous) cells called an adenomatous polyp. Most of these polyps will not become malignant (cancerous), but some can slowly turn into cancer over the course of about 10-15 years.
Signs and symptoms of colon cancer include: A persistent change in your bowel habits, including diarrhea or constipation or a change in the consistency of your stool. Rectal bleeding or blood in your stool. Persistent abdominal discomfort, such as cramps, gas or pain.
Depending on their size and location in the colon, serrated polyps may become cancerous. Small, serrated polyps in the lower colon, also known as hyperplastic polyps, are rarely malignant. Larger serrated polyps, which are typically flat (sessile), difficult to detect and located in the upper colon, are precancerous.
Approximately 6% of colorectal cancers are diagnosed within 3 to 5 years after the patient received a colonoscopy, according to findings from a recent population-based study.
Screening for colorectal cancer
Colorectal cancer doesn't just appear suddenly. It starts as a small growth on your colon, called a polyp, which rarely causes symptoms. If left alone over many years, polyps can grow into cancer. The only way to know it's there is to look.
Colorectal cancer symptoms may be minor or non-existent during the early stages of the disease, although there may be some early warning signs. The symptoms of colorectal cancer may not develop until the disease has progressed into stage 2 or beyond.
The 3 main symptoms of bowel cancer are blood in the stools (faeces), changes in bowel habit – such as more frequent, looser stools – and abdominal (tummy) pain. However, these symptoms are very common and most people with them do not have bowel cancer.
Colon cancer can cause both constipation and diarrhea. A person may feel cramp-like pain in the stomach. The stool may be streaked or mixed with blood. In rectal cancer, the most common symptom is usually bleeding when going to the bathroom.
A CT scan uses x-rays to make detailed cross-sectional images of your body. This test can help tell if colorectal cancer has spread to nearby lymph nodes or to your liver, lungs, or other organs.
Aging — Polyps and colorectal cancers are uncommon before age 40. Ninety percent of cases occur after age 50, with males somewhat more likely to develop polyps than females; therefore, colon cancer screening is usually recommended starting at age 50 for both sexes.
The specific type of surgery is determined by the location of the disease. Four common types are: right hemicolectomy, sigmoid colectomy, left hemicolectomy, and low anterior resection (LAR).
The right colon consists of the cecum, ascending colon, hepatic flexure and the right half of the transverse colon. The left colon consists of the left half of the transverse colon, splenic flexure, descending colon, and sigmoid.
In most cases, colon and rectal cancers grow slowly over many years. Most of those cancers start as a growth called a polyp.
But if a tumor develops into a carcinoma with the ability to metastasize, it will progress to metastasis quickly. This transformation occurs within about two years, before another mutation can develop.
In general, colorectal cancers tend to be slow growing, gradually enlarging and eventually penetrating the bowel wall. When they do spread, it is usually through invasion of nearby lymph nodes. In fact, cancer cells may enter a lymph node even before the tumor penetrates through the intestinal wall.
Care begins with cancer staging
During a colonoscopy, your doctor will remove polyps, abnormal growths in the colon that can become cancerous. If biopsy results show cancer, the next step would be imaging tests for diagnosing cancer. Imaging tests check whether the cancer has spread to any organ or lymph nodes.