People typically aren't diagnosed with colorectal cancer in their 20s or 30s. Recommended screening doesn’t even start until age 50. But colorectal cancer is indeed increasing in younger folks, and these young patients may have a tough battle ahead.
Patients under the age of 40 who have colorectal cancer that has spread to other areas of the body didn't respond well to treatment, a new study found.
Compared to middle-aged patients, this younger group had a poorer overall outlook.
Christopher Lieu, MD, a University of Colorado Cancer Center investigator and assistant professor at CU's School of Medicine, led a team of scientists who wanted to know if age was a predictor of overall survival and progression-free survival (PFS), a measure of the length of time in which the disease does not get worse.
The average age at colorectal cancer diagnosis is 69. Patients younger than 50 make up only a fraction (4.6 percent) of colorectal cancer patients, but that fraction is growing rather dramatically, the researchers learned.
Looking at the number of cases between 1992 and 2005, the investigators uncovered that colorectal cancer incidence has been increasing 5.2 percent a year in 20- to 29-year-old men and 5.6 percent in women in the same age group.
Annual increases in the 30- to 39-year-old age group have been 3 percent for men and 2 percent for women.
Young patients are commonly diagnosed in later stages of the disease — stage lll and lV.
"The reasons why the incidence of colorectal cancer is increasing in younger patients remain unknown, although genetic predisposition, environmental factors, fewer early cancer detections in this population or a combination of these factors are thought to play a role," Dr. Lieu said in a statement.
The research team looked at studies in a database of clinical trials analyzing advanced colorectal cancer supported by the French "Aide et Recherche en Cancérologie Digestive" Foundation (ARCAD).
These studies included 20,034 patients from 24 phase III clinical trials who were undergoing their first treatment for colorectal cancer.
The researchers were able to evaluate lifespan and progression-free survival in 19,900 of these patients, 3 percent or 695 of whom were under the age of 40.
The study found that compared to middle-aged patients, the youngest and the oldest patients had the highest risk of the disease getting worse or death. Patients between the ages of 57 and 61 at the time of diagnosis had the lowest risks of disease progression or death.
People under the age of 40 had a 30 percent greater risk of dying from colorectal cancer and a 28 percent increased chance of the cancer spreading during the first year compared to 57-year-olds.
The oldest colorectal cancer patients had a 72 percent higher risk of death and a 19 percent greater risk of the disease progressing during the first year, compared to middle-aged patients.
“Young patients with metastatic colorectal cancer represent a high-risk population for treatment failure and further studies identifying biological differences are warranted,” the authors concluded.
“This is a very interesting study and is strengthened by the large number of clinical trial patients that were analyzed,” David Shibata, MD, chief of the section of Colorectal Oncology at Moffitt Cancer Center in Tampa, Florida, told dailyRx News.
“A well-known observation is that patients with early stage colon cancers with a particular biological feature known as microsatellite instability generally do not benefit from post-operative chemotherapy,” Dr. Shibata explained.
“Microsatellite instability can often be found in tumors from young patients with hereditary colon cancer conditions and it would be of interest to determine the status of this feature in the patients from this current study. Certainly, research to identify a biological basis for the findings of this study would be very helpful as a step to achieve personalized treatment in younger patients with colon cancer,” said Dr. Shibata, who was not involved in this study.
Dr. Lieu is collaborating with researchers from The University of Texas MD Anderson Cancer Center to see if biological differences may be the reason for the higher mortality rates in younger colorectal cancer patients.
Results of this study were presented at the 2013 European Cancer Congress (ECC2013). Before publication in a peer-reviewed journal, all research is considered preliminary.
No conflicts of interest were disclosed.