January 25, 2016
4 min read
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Colorectal cancer incidence rising in patients younger than screening age

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Approximately 15% of patients diagnosed with colorectal cancer received their diagnosis at an age younger than 50 years, according to the results of a SEER analysis.

Perspective from Jimmy Hwang, MD, FACP

Although younger patients tend to present with more advanced-stage tumors, they also receive more aggressive therapy and, thus, achieve longer DFS, research showed.

Samantha Hendren

“Colorectal cancer has traditionally been thought of as a disease of the elderly,” Samantha Hendren, MD, MPH, associate professor of colorectal surgery at University of Michigan Health Systems, said in a press release. “This study is really a wake-up call to the medical community that a relatively large number of colorectal cancers are occurring in people under 50.”

Researchers have estimated that more than one in 10 colorectal cancers and one in four rectal cancers will be diagnosed in individuals aged younger than 50 years by 2030, according to study background.

Despite these estimates, treatment patterns and outcomes among this younger cohort have not been extensively studied.

Thus, Hendren and colleagues sought to determine the effect of receiving a diagnosis of colorectal cancer before the screening age of 50 years on disease stage at presentation, treatment patterns by disease stage and adjusted cancer-specific survival. They used the SEER registry to identify patients diagnosed with colorectal cancer between 1998 and 2011.

The study included data from 258,024 patients with colorectal cancer, of whom 14.7% (n = 37,847) received their diagnosis at an age younger than the recommended screening interval for average-risk individuals (mean age, 42.5 ± 6 years).

Compared with older patients, these patients appeared more likely to be black (14.8% vs. 12%), and American Indian/Alaska Native or Asian/Pacific Islander (10.6% vs. 8.5%; P < .001 for all).

Further, younger patients appeared more likely to present with regional (RR = 1.37; 95% CI, 1.34-1.41) or distant (RR = 1.58; 95% CI, 1.53-1.63) disease.

Most patients underwent surgery for their primary tumor. However, a greater proportion of patients aged younger than 50 years received surgery than older patients, especially among those with distant disease (70.8% vs. 66.6%; P < .001).

Receipt of radiotherapy also appeared more common among younger patients with localized (36.2% vs. 29.7%), regional (82.4% vs. 77.7%) and distant disease (49.1% vs. 41.9%; P < .001 for all).

Although younger patients presented with more advanced disease, researchers found adjusted cancer-specific survival was improved in the younger vs. older cohort across all stages of disease, including localized (95.1% vs. 91.9%), regional (76% vs. 70.3%) and distant disease (21.3% vs. 14.1%; P < .001 for all).

The researchers acknowledged study limitations, including the risk for selection bias inherent in observational studies and the inability to ascertain causation. They further noted that a higher percentage of younger patients may have a hereditary cancer syndrome.

“Colorectal cancer is increasingly being diagnosed in young adults who are too young for average-risk screening,” Hendren said. “Current screening guidelines recommend against routine screening for ‘average-risk’ individuals aged younger than 50 years, and therefore younger patients are often diagnosed only after they become symptomatic.”

However, these data may not warrant the immediate revision of screening guidelines.

“This would be a big and costly change, and I don’t know whether it would help more people than it would hurt,” Hendren said. “A lot of research would be required to understand this before any changes should be made.”

Still, this research can help bring about awareness.

“In a practical sense, [these data mean] that we should look out for warning signs of colorectal cancer such as anemia, a dramatic change in size of frequency of bowel movements, and dark blood or blood mixed with the stool in bowel movements,” Hendren said. “Also, people with a positive family history for colorectal cancer (in first-degree relatives, such as parents or siblings) and some others who are at higher risk should begin screening earlier than 50. This is already recommended, but we don’t think this is happening consistently, and this is something we need to optimize.” – by Cameron Kelsall

Disclosure: The researchers report no relevant financial disclosures.