John L. Marshall, MD
Historically, colorectal cancer (CRC) has been considered a disease of aging. The median age at diagnosis for colon cancer is 68 years in men and 72 years in women, and the median age at diagnosis for rectal cancer is 63 years in both sexes.1
However, an American Cancer Society (ACS) study published in 2017 reported that although CRC incidence in the United States is declining overall due to improved screening, it is rapidly increasing among young and middleaged adults (<50 years).2
The study found that CRC rates have increased by 1.0% to 2.4% annually since the mid-1980s among adults aged 20 to 39 years and by 0.5% to 1.3% since the mid-1990s among adults aged 40 to 54 years.2 Subsequently, the proportion of CRC cases diagnosed in individuals younger than 50 years increased from 6% in 1990 to 11% in 2013, with the majority (72%) being in individuals in their 40s.1
Since early-onset CRC is a relatively recently recognized phenomenon, particularly among adolescents and very young adults, data on this population are still limited. However, the panelists shared their experiences treating early-onset CRC, discussing tumor features, CRC screening, patient characteristics, treatment approaches, and special considerations for younger patients as part of a broader conversation about individualizing care for patients with the disease.
Early-onset CRC, like CRC in older adults, is considered a heterogenous disease. Some cases appear to have a hereditary component (~15%- 20%), although the majority appear to be sporadic.3
Clinicopathologic and molecular features that have been more commonly observed in earlyversus late-onset CRC have been reported previously (Table 1
Table 1. Clinicopathologic and Molecular Features More Commonly Observed in Early-Onset CRC3
“The biology appears to be much more aggressive in quite a few of these patients, much more so than in our older patients, and they’re not responding to the therapies that we’ve been giving as a standard to all of our other patients,” Cathy Eng, MD, FACP, said. “It seems like a different cancer,” Marshall chimed in.
The panel discussed rightand left-sided CRCs, the latter of which have generally been associated with an improved prognosis. “I think we all know [that patients with early-onset CRC are] presenting more often with left-sided tumors and rectal tumors. We’re told the left-sided tumors have better survival, but this seems a little bit different in this unique young patient population,” Eng said, adding that peritoneal disease is another common presentation. The panel acknowledged that the later stage at diagnosis is likely a major contributing factor to these patients’ worse outcomes, making improved screening essential.
Based on the finding that CRC rates are increasing in younger populations, particularly those in their 40s, the ACS recently lowered the age at which to begin CRC screenings in average-risk persons, from age 50 years to 45 years.4 However, this move may be insufficient, since it does not improve detection among adolescents, young adults, and those in their early 40s, the group that may be at greatest risk.
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