In a worrying trend, not only are colorectal cancer rates rapidly rising among adults in their 20s, 30s and 40s, but the early warning signs are not being detected fast enough, according to a recent scientific review.
The most common early indicator is passing blood in the stool, but the researchers said adults under 50 are less likely to have colonoscopies that can catch cancers and precancerous polyps, and are more likely to ignore these warning signs, reports The New York Times.
The analysis, which looked at 81 studies that included nearly 25m adults under 50 from around the world, found that rectal bleeding is associated with a fivefold increased risk of colorectal cancer.
Abdominal pain, changes in bowel habits and anaemia are other common warning signs of the disease that should not be ignored, according to the findings, published in JAMA Network Open.
Why it matters
While colon and rectal cancer rates are increasing among younger adults, rates have declined among older people, because they are more likely to undergo colonoscopies that would pick up cancers and precancerous lesions.
But although millennials born around 1990 are at almost twice the risk of colon cancer compared with people born in the 1950s, and have a risk of rectal cancer that is four times as high, young people without a strong family history of colon cancer aren’t eligible for colonoscopies until the age of 45 in the US.
Doctors may also miss the warning signs. Anecdotal evidence suggests that because physicians are less likely to suspect malignancies in younger people, they may attribute a symptom like rectal bleeding to a benign condition like haemorrhoids, rather than cancer, said Joshua Demb, a cancer epidemiologist at the University of California-San Diego, and one of the paper’s lead authors.
Analyst found that when younger adults first go to a doctor with a complaint about a symptom, it can then take four to six months on average until they receive a diagnosis. So because the diagnosis is often delayed, they then tend to have more advanced disease that is harder to treat.
What we don’t know
The causal factors driving the rise in colon and rectal cancers in younger adults were not addressed in the analysis, and are not well understood.
Colorectal cancer has long been associated with obesity, smoking, a sedentary lifestyle, high alcohol intake and diets that are rich in red meat, processed food and sugary drinks.
The research exploring the rapid rise in colorectal cancer in younger adults is examining other possible causes, including environmental exposures, changes in gut bacteria and the use of some medications, like antibiotics.
Study details
Red Flag Signs and Symptoms for Patients With Early-Onset Colorectal CancerA Systematic Review and Meta-Analysis
Joshua Demb, Jennifer Kolb, Jonathan Dounel.
Published in JAMA Network Open on 24 May 2024
Key Points
Question In patients with early-onset colorectal cancer (EOCRC), what are the most common presenting signs and symptoms, what is their association with EOCRC risk, and what is the time from presentation to diagnosis?
Findings In this systematic review and meta-analysis including 81 studies and more than 24.9m patients, nearly half of individuals with EOCRC presented with haematochezia and abdominal pain and one-quarter presented with altered bowel habits. Delays in diagnosis of four to six months from time of initial presentation were common.
Meaning These findings underscore the need to identify signs and symptoms concerning for EOCRC and complete timely diagnostic workup for individuals without an alternative diagnosis or sign or symptom resolution.
Abstract
Importance
Early-onset colorectal cancer (EOCRC), defined as a diagnosis at younger than age 50, is increasing, and so-called red flag signs and symptoms among these individuals are often missed, leading to diagnostic delays. Improved recognition of presenting signs and symptoms associated with EOCRC could facilitate more timely diagnosis and impact clinical outcomes.
Objective
To report the frequency of presenting red flag signs and symptoms among individuals with EOCRC, to examine their association with EOCRC risk, and to measure variation in time to diagnosis from sign or symptom presentation.
Data Sources
PubMed/MEDLINE, Embase, CINAHL, and Web of Science were searched from database inception until May 2023.
Study Selection
Studies that reported on sign and symptom presentation or time from sign and symptom presentation to diagnosis for patients younger than 50 diagnosed with non-hereditary CRC were included.
Data Extraction and Synthesis
Data extraction and quality assessment were performed independently in duplicate for all included studies using Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guidelines. Joanna Briggs Institute Critical Appraisal tools were used to measure risk of bias. Data on frequency of signs and symptoms were pooled using a random-effects model.
Main Outcomes and Measures
Outcomes of interest were pooled proportions of signs and symptoms in patients with EOCRC, estimates for association of signs and symptoms with EOCRC risk, and time from sign or symptom presentation to EOCRC diagnosis.
Results
Of the 12 859 unique articles initially retrieved, 81 studies with 24 908 126 patients younger than 50 were included. The most common presenting signs and symptoms, reported by 78 included studies, were haematochezia (pooled prevalence, 45% [95% CI, 40%-50%]), abdominal pain (pooled prevalence, 40% [95% CI, 35%-45%]), and altered bowel habits (pooled prevalence, 27% [95% CI, 22%-33%]). Haematochezia (estimate range, 5.2-54.0), abdominal pain (estimate range, 1.3-6.0), and anaemia (estimate range, 2.1-10.8) were associated with higher EOCRC likelihood. Time from signs and symptoms presentation to EOCRC diagnosis was a mean (range) of 6.4 (1.8-13.7) months (23 studies) and a median (range) of 4 (2.0-8.7) months (16 studies).
Conclusions and Relevance
In this systematic review and meta-analysis of patients with EOCRC, nearly half of individuals presented with haematochezia and abdominal pain and one-quarter with altered bowel habits. Haematochezia was associated with at least 5-fold increased EOCRC risk. Delays in diagnosis of four to six months were common. These findings highlight the need to identify concerning EOCRC signs and symptoms and complete timely diagnostic workup, particularly for individuals without an alternative diagnosis or sign or symptom resolution.
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