Importance of Location of Colon Cancer


Robert Preidt recently submitted an article on the importance of where your colon cancer is located. This can affect a patient’s chances for survival, according to a new report. There are so-called left-sided and right-sided colon cancers, and an oncologist who reviewed the findings explains. Dr. David Bernstein, chief of hepatology at Northwell Health in Manhasset, NY says that the left-sided cancers are located closer to the anus and located in the rectum, sigmoid colon and descending colon. These usually present with bleeding or partial obstruction and patients tend to seek medical care earlier. But then the right-sided lesions located in the first part of the colon and near the junction with the small intestine, do not typically present with obstruction but tend to present with anemia and are more likely to be associated with metastatic disease, especially to the liver.

They are quite often detected later in their progression so these right-sided colon tumors have a worse prognosis than left-sided colon cancers. There were 66 studies where a team led by Dr. Fausto Petrelli of the ASST Bergamo Ovest, in Treviglio, Italy, reviewed data from 66 studies. This involved a total of more than 1.4 million patients who were followed for a median of more than 5 years.

The colon cancer patients with left-sided tumors were nearly 20% less likely to die than those whose tumors occurred on the right side. There seemed to be more than simply later detection, as the Italian team noted. The difference in survival between the left and right-sided colon cancer held even after the researchers factored out cancer stage at diagnosis. Prior research has shown that right and left colon cancers are genetically distinct, as well.

These new findings show that primary tumor locations should be carefully considered when deciding treatment intensity. Findings were reviewed by another oncologist who said that they have implications for patients deciding on which tool – a sigmoidoscope or colonoscope – to opt for in colon cancer screening.

Dr. Jules Garbus, a colorectal surgeon at Winthrop-University Hospital in Mineola says the report reaffirms the importance of choosing the appropriate screening tool for the prevention and detection of colon cancer. The sigmoidoscopy provides a limited exam of the left side of the colon from the anus directly up to the left upper abdomen and colonoscopy is a complete exam of the entire colon which extends past where the sigmoidoscopy reaches. It crosses over to the right side of the abdomen and down to the right lower abdomen. This study suggests that the location of the cancer may be an integral part of establishing prognosis and treatment, therefore colonoscopy remains the gold standard in colon cancer screening. The study can be found in the journal JAMA Oncology.

Dr Fredda Branyon