Adults with iron-deficiency anemia (IDA) or hematochezia diagnosed before 50 years of age should likely be assessed by colonoscopy for young-onset colorectal cancer (YCRC), according to the results of a retrospective cohort study published in Gut.

A team of researchers assessed medical records of veterans aged 18 to 49 years treated within the Veterans Health Administration system in the United States. Patients treated for IDA (n=47,800) or hematochezia (n=130,748) were matched for age, gender, and visit date with a control cohort of patients treated for other reasons (no IDA: n=191,200; no hematochezia: n=522,992).

Among the entire IDA and no IDA cohort, patients had a median age of 42 years, 53.0% were women, 48.8% were White, median body mass index was 28.8, 7.9% had diabetes, and 7.4% used aspirin.


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A total of 257 YCRC diagnoses were made, in which 184 (0.45%) of the diagnoses were among the veterans with IDA and 73 (0.05%) were among those without IDA (risk difference [RD], 0.39%; 95% CI, 0.33-0.46). Risk for YCRC was higher among veterans with IDA (adjusted hazard ratio [HR], 10.81; 95% CI, 8.15-14.33) vs those without IDA.

Risk for YCRC at 5 years was associated with age and gender and was found to be increased among men with IDA aged younger than 30 years (HR, 38.76; 95% CI, 4.50-334.13), aged 30 to 39 years (HR, 11.96; 95% CI, 3.76-38.08), and aged 40 to 49 years (HR, 13.95; 95% CI, 9.81-19.85) and among women with IDA aged 30 to 39 years (HR, 13.99; 95% CI, 2.76-70.85) and aged 40 to 49 years (HR, 3.23; 95% CI, 1.65-6.31).

Among those with and without hematochezia, median age was 42 years, 12.6% were women, 53.4% were White, median body mass index was 29.0, 6.8% had diabetes, and 6.5% used aspirin.

A total of 406 YCRC diagnoses were made, in which the veterans with hematochezia had an increased rate of diagnosis (RD, 0.30%; 95% CI, 0.26-0.33). Overall, risk for YCRC was 10.66-fold higher among patients with hematochezia (95% CI, 8.76-12.97) vs those without hematochezia.

Similar to that identified in patients with IDA, risk for YCRC at 5 years was associated with age and gender and increased among men with hematochezia aged younger than 30 years (HR, 10.24; 95% CI, 2.31-45.30), aged 30 to 39 years (HR, 15.68; 95% CI, 7.56-32.52), and aged 40 to 49 years (HR, 9.85; 95% CI, 7.97-12.18) and among women with hematochezia aged 30 to 39 years (HR, 25.35; 95% CI, 5.30-121.30) and aged 40 to 49 years (HR, 15.99; 95% CI, 5.81-44.05).

Within 60 days or at 5 years following a diagnosis of IDA, 28% and 17% of patients underwent colonoscopy, respectively. Colonoscopy was more common among patients receiving a diagnosis of hematochezia (59% at 60 days and 46% at 5 years).

This study was potentially biased by missing information, as veterans who sought care outside of the Veterans Health Administration system were not accounted for, and information about family history of CRC was unavailable.

These data indicated YCRC was elevated among individuals aged 18 to 49 years who had been diagnosed with IDA or hematochezia. Despite this elevated risk, few individuals were assessed by colonoscopy; therefore, these observations may indicate clinical guidelines should be re-evaluated.

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Reference

Demb J, Liu L, Murphy CC, Doubeni CA, Martínez ME, Gupta S. Young-onset colorectal cancer risk among individuals with iron-deficiency anaemia and haematochezia. Gut. Published online December 18, 2020. doi:10.1136/gutjnl-2020-321849