As the number of cases of early-onset colorectal cancer (CRC) diagnosed before age 50 continues to rise, early detection has become increasingly important.
The signs and symptoms are abdominal pain, rectal bleeding, diarrhea, and iron-deficiency anemia.
Two symptoms in particular – rectal bleeding and iron-deficiency anemia – point to the need for timely endoscopy and follow-up, the researchers say.
“Colorectal cancer is not simply a disease affecting older people; we want younger adults to be aware of and act on these potentially very telling signs and symptoms – particularly because people under 50 are considered to be at low risk, and they don’t receive routine colorectal cancer screening,” senior investigator Yin Cao, ScD, with Washington University School of Medicine, St. Louis, said in a news release.
“It’s also crucial to spread awareness among primary care doctors, gastroenterologists, and emergency medicine doctors,” Dr. Cao added. “To date, many early-onset colorectal cancers are detected in emergency rooms, and there often are significant diagnostic delays with this cancer.”
The study was published online in the Journal of the National Cancer Institute.
Although previous research has identified rectal bleeding, iron-deficiency anemia, and rectal/abdominal pain as symptoms of early-onset CRC, most studies “have aggregated symptoms till the time of diagnosis,” which limits their use for early detection, the authors explain.
In the current study, the researchers analyzed data from more than 5,000 cases of early-onset CRC and from more than 22,000 control patients using the IBM MarketScan commercial database.
Dr. Cao and colleagues found that between 3 months and 2 years before diagnosis, abdominal pain, rectal bleeding, diarrhea, and iron-deficiency anemia each indicated an increased risk for early-onset CRC.
Among patients with early-onset CRC, 19.3% presented with one or more of the four red flags between 3 months and 2 years prior to the index date; 15.6% had one symptom, and 3.7% had two or more.
After multivariable adjustment, having one symptom almost doubled the risk for early-onset CRC (odds ratio, 1.94); having two symptoms increased risk by more than threefold (OR, 3.59); and having three or more boosted the risk by more than 6.5-fold (OR, 6.52).
Abdominal pain was associated with a 34% higher risk of early-onset CRC (11.6% among case patients vs. 7.7% among controls; OR, 1.34).
Although not as common, rectal bleeding was associated with the highest odds for early-onset CRC (7.2% case patients vs. 1.3% controls; OR, 5.13).
The other predictive signs and symptoms included diarrhea (2.8% case patients vs. 1.4% controls; OR, 1.43) and iron-deficiency anemia (2.3% case patients vs. 0.9% controls; OR, 2.07).
No differences were observed by gender for each sign or symptom.
Among patients with a red-flag symptom who presented between 3 months and 2 years before diagnosis, for those with early-onset CRC, the median diagnostic interval was 8.7 months.
The researchers suggest that clinicians prioritize prompt diagnostic workups for patients younger than 50 who present with rectal bleeding and/or iron-deficiency anemia and that they also keep abdominal pain and diarrhea in mind as early symptoms.
Dr. Cao noted that since most early-onset CRC cases “have been and will continue to be diagnosed after symptom presentation, it is crucial to recognize these red-flag signs and symptoms promptly and conduct a diagnostic workup as soon as possible.
“By doing so, we can diagnose the disease earlier, which in turn can reduce the need for more aggressive treatment and improve patients’ quality of life and survival rates,” said Dr. Cao.
The study was supported by grants from the National Institutes of Health. The authors declared no conflicts of interest.
A version of this article originally appeared on Medscape.com.