Daijiworld Media Network – Louisville

Louisville, Oct 4: A new study has found that rectal bleeding is the strongest predictor of colorectal cancer in adults under 50, increasing the risk by a staggering 850%.

The research, conducted at University of Louisville Health, examined the medical records of 443 patients under 50 who underwent colonoscopies between 2021 and 2023. Nearly half were diagnosed with early-onset colorectal cancer, with rectal bleeding emerging as the most alarming symptom.

“Many of the early-onset colorectal cancers that I see have no family history,” said Dr Sandra Kavalukas, colorectal surgeon at the University of Louisville School of Medicine. “This research shows that if a younger patient presents with rectal bleeding, a colonoscopy should be strongly considered.”

Key findings of the study:

• Symptom-driven diagnosis: 88% of patients later found with early-onset colorectal cancer underwent colonoscopy due to symptoms like bleeding, compared to 55% of non-cancer patients.
• Genetics not dominant: Only 13% of early-onset colorectal cancer cases were linked to hereditary markers. Family history increased risk two-fold, but symptoms were a stronger indicator.
• Lifestyle risks: Patients with the disease were nearly twice as likely to be former smokers.

Currently, guidelines recommend colorectal cancer screening from age 45 for average-risk individuals. However, with rising cases in younger adults, experts warn that many high-risk patients may be overlooked.

“If they’re 35 and come in with rectal pain, they probably don’t need a colonoscopy,” Dr Kavalukas explained. “But if they present with rectal bleeding, they are 8.5 times more likely to have colorectal cancer.”

The findings highlight the need for symptom-based screening decisions to detect colorectal cancer earlier among younger adults.