A new study from the American Cancer Society has found that more people living in the United States of America are dying from colon and rectal cancers around the age of 50 years when they are supposed to officially begin screening for these cancers. The new study is published in the JAMA, the Journal of the American Medical Association.
Routine screenings are recommended for adults over the age of 50 years. According to experts, the cancers that are diagnosed before the age of 50 years or among younger adults are deadlier and often caught at more advanced stages. This latest study is a follow up of a previous study. This earlier study shows that adults born in 1990 may have twice the risk of colon cancer and four times the risk of rectal cancer at the same age compared to adults born in 1950. The rates of new cases diagnosed as well as the number of deaths due to these cases both are high and the cause of this rise is unknown.
Rebecca Siegel, an epidemiologist at the American Cancer Society and lead author of the new study explained that it was already known that people under 50 are getting diagnosed and may erroneously mean they are being screened more and earlier with colonoscopies. However this new study shows that more number of cases does not mean that more colonoscopies are done so more cases are being detected. If that were the case, the death rates would decline since colonoscopies could detect the cancers early when treatment is more likely to be successful.
The latest study looked at colon and rectal cancer diagnoses and deaths among adults aged 20 to 54 years in the United States from 1970 to 2014. The death rates were obtained from the National Cancer Institute's Surveillance, Epidemiology and End Results Program. These reports came from the National Center for Health Statistics, which tracks cause-specific death rates in around 250,000 people.
Results showed that colon and rectal cancer death rates among 20- to 54-year-olds had reduced overall from 1970 to 2004 and then steadily rose by 1% each year for ten years till 2014. The rates were 6.3 per 100,000 in 1970 and fell to 3.9 in 2004. Finally the total colorectal cancer death rate was 4.3 people per 100,000 in 2014.
According to Siegel the death rates are higher among whites than among African Americans. Among blacks there is a slight decline in the rates of deaths over the 45 years of the study. Death rates for white reduced first and then began rising since 2004 becoming 4.1 per 100,000 in 2014 from 3.6 in 2004. For blacks, the numbers reduced to 6.1 per 100,000 in 2014. This was a rather surprise finding she said because the risk factors for colorectal cancer for both whites and blacks are the same. The cause for this difference is thus unknown.
She emphasized however that the risk of getting colorectal cancers below the age of 55 years is still low and there is no cause for alarm. But the death rates are dependent on several factors including the stage of the cancer, the time of the diagnosis, treatments that the patient has already received, molecular type of the cancer.
Apart from skin cancer, colorectal cancer is the third most common cancer diagnosed in both men and women in the United States. In 2017, the American Cancer Society estimates there would be 95,520 new cases of colon cancer and 39,910 new cases of rectal cancer by end of this year. A lifetime risk for developing colorectal cancer is thus about 1 in 21 (4.7%) for men and 1 in 23 (4.4%) for women. Colorectal cancer is the second leading cause of cancer-related deaths in men and third leading cause of death among women in the United States. Worldwide, colorectal cancer is the third most common cancer.
Colorectal cancer is a cancer that starts in the colon or the rectum. Colon cancer and rectal cancer are clubbed together because they have similar features. Most colorectal cancers begin as a growth called a polyp on the inner lining of the colon or rectum. These polyps may change to become cancers.
Adenocarcinomas make up more than 95% of colorectal cancers. Other, less common types of tumors can also start in the colon and rectum including carcinoid tumours, Gastrointestinal stromal tumors (GISTs), lymphomas, sarcomas etc.
There may be little or no symptoms at the initial stages of bowel cancer. There may be blood or mucus in the stools, an unexplained change in bowel habits with prolonged diarrhea or constipation, loss of appetite and unexplained weight loss.
Bowel cancer can be treated using a combination of surgery, chemotherapy and radiotherapy. Some individuals may also benefit from biological therapy.