December 25, 2015
16 min read

Soaring incidence of young-onset colorectal cancer raises questions about screening, treatment

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Colorectal cancer incidence and mortality are at historic lows.

SEER data indicate incidence of new colon and rectum cancers in the United States decreased 3.1% annually over the past decade. Further, mortality rates declined 2.8% yearly from 2003 to 2012.

Despite these favorable statistics, the data reveal alarming trends.

Colon cancer incidence among Americans aged 20 to 34 years is expected to increase 90% by 2030, according to an analysis of SEER data. Incidence of rectosigmoid and rectal cancers is expected to increase 124.2% in that period.

Because few younger individuals undergo colorectal cancer screening, they often present with more advanced-stage and poorly differentiated disease. Even when they present with colorectal cancer symptoms — such as blood in the stool or abdominal pain — clinicians initially may suspect other causes, such as hemorrhoids or a gastrointestinal disorder.

Genetics appear to account for approximately 20% of colorectal cancers in younger adults; however, isolating the causes of most cases has proven difficult.

“Nobody honestly knows why this is happening,” Christopher Lieu, MD, assistant professor in the division of medical oncology at University of Colorado Denver’s School of Medicine, told HemOnc Today.

Lifestyle factors — such as obesity or lack of physical activity — have been cited as potential contributors, as has the high concentration of red meats and processed foods in the typical Western diet.

Still, the spike in colorectal cancer incidence in otherwise healthy young Americans likely is multifactorial, Lieu said.

“A diet that is high in red meat and processed food will increase your [cancer] risk, but it only slightly increases the risk for colon cancer, so there has to be something else going on,” Lieu said. “It is most likely a combination of diet, environment and genetics. It is not all one or the other.”

HemOnc Today spoke with oncologists and gastroenterologists about the increased incidence of colon and rectal cancers in younger adults, how these patients respond to treatment, whether broader screening parameters are necessary, and how prevention and treatment efforts must evolve to increase the likelihood of positive outcomes among younger patients.

Treatment outcomes

Young-onset colorectal cancers are relatively rare in the United States. Individuals aged younger than 50 years account for 11% of colon cancers and 18% of rectal cancers.

However, the projected increased incidence has prompted the research community to consider whether current screening and treatment guidelines are appropriate for this demographic.

Prospective data that compare standard colorectal cancer treatments in younger vs. older populations are scarce, but retrospective data show outcomes vary considerably by age.

Although young adults may be more likely to prefer aggressive therapy to extend their lives, research has shown some of these patients do not respond to intense therapy as well as middle-aged patients.

Lieu and colleagues conducted a study within the ARCAD clinical trials program — published in 2015 in Journal of Clinical Oncology — that showed the youngest and oldest patients with colorectal cancers are at increased risk for death and progression compared with middle-aged patients.

The risk for death appeared lowest among patients aged 57 years, and the risk for progression or death appeared lowest among those aged 61 years.

Compared with these middle-aged reference groups, the youngest patients — or those near age 18 years — demonstrated a 19% (95% CI, 7-33) increased risk for death and a 22% (95% CI, 10-35) increased risk for progression or death. The oldest patients, or those aged near 90 years, demonstrated a 42% (95% CI, 31-54) increased risk for death and 15% (95% CI, 7-24) increased risk for progression or death.

These disparities may be a reflection of differing tumor biology or of a greater tumor burden due to lower screening rates in these cohorts, Lieu said.

Data from Kneuertz and colleagues — published in 2015 in JAMA Surgery — showed 61.8% of adults aged 18 to 49 years with colon cancer presented with stage III or stage IV disease.


Younger patients in this cohort appeared more likely to receive systemic chemotherapy compared with older patients whether they had stage I (OR = 2.88; 95% CI, 2.21-3.77), stage II (OR = 3.93; 95% CI, 3.58-4.31), stage III (OR = 2.42; 95% CI, 2.18-2.68) or stage IV disease (OR = 2.74; 95% CI, 2.44-3.07). However, this more intense treatment did not contribute to a significant survival benefit among patients with stage II (RR = 0.9; 95% CI, 0.69-1.17), stage III (RR = 0.89; 95% CI, 0.81-0.97) or stage IV disease (RR = 0.84; 95% CI, 0.79-0.9).

“We know that we are able to treat younger patients and that they are able to receive more therapy,” study researcher George J. Chang, MD, MS, professor in the departments of surgical oncology and health services research and chief of colon and rectal surgery at The University of Texas MD Anderson Cancer Center, told HemOnc Today. “That could mean we are treating the wrong people or that they are not responsive to our current treatments. Our tendency is to treat young patients harder, but it hasn’t been associated with a commensurate improvement in outcome.”

Tumor biology may have the greatest impact on outcomes, C. Richard Boland, MD, chief of gastroenterology and medical director of epigenetics and cancer prevention at Baylor University Medical Center in Dallas, told HemOnc Today.

“These tumors are biologically different,” Boland said. “Seventy-nine percent of the colorectal cancers in young patients are in the rectum or the rectosigmoid. They are mostly distal tumors, and there’s really no explanation yet for why that is.”

LINE-1 hypomethylation could play a role, Boland added.

“This could predispose patients to chromosomal instability, because you are getting hypomethylation near the centromeres and the telomeres, which predisposes the chromosomes to stick to one another and have unbalanced mitoses,” he said. “That’s the way to generate a dangerous tumor with lots of chromosomal rearrangements. When you get rearrangements, you activate oncogenes and you get these really nasty tumors.”

Because young adults with colorectal cancer tend to experience outcomes comparable to elderly patients despite these unfavorable tumor characteristics, it is difficult to say whether the younger cohort is overtreated, Jason A. Zell, DO, MPH, associate professor of medicine and epidemiology and program director of the hematology/oncology fellowship training program in the school of medicine at University of California, Irvine, said in an interview.

Jason A. Zell, DO, MPH
Jason A. Zell

“The bottom line is, young adults with colon cancer have more aggressive biologic features that are usually associated with a poor outcome and they do as well or better than the older cohorts,” Zell said. “This area is a little bit muddy. It is very hard for us to say they are overtreated without benefit when there are all of these confounding variables associated with young-onset colon cancer, which gives them more aggressive disease to start with.”

Genetic biomarkers

Researchers hope to identify genetic biomarkers that may increase the risk for young-onset colorectal cancer.

Data from Mork and colleagues — published this year in Journal of Clinical Oncology — showed the prevalence of hereditary cancer syndromes appeared higher in younger patients with colorectal cancer than in the overall population with the disease.

Among 193 patients with colorectal cancer aged younger than 35 years, 67 (34.7%) had an identifiable hereditary cancer syndrome. They included 23 patients with Lynch syndrome, 22 with mutation-negative Lynch syndrome, 16 with familial adenomatous polyposis, two with constitutional mismatch repair deficiency, two with biallelic MUTYH mutations, one with Li-Fraumeni syndrome and one with a monoallelic MUTYH mutation.

“We hope that physicians and other health providers treating patients diagnosed with colorectal cancer under age 35 years are aware of the high prevalence of hereditary cancer syndromes and, therefore, send them for genetic counseling and consideration of genetic testing,” researcher Eduardo Vilar-Sanchez, MD, PhD, assistant professor in the department of clinical cancer prevention at The University of Texas MD Anderson Cancer Center, told HemOnc Today at the time the study was published. “The next step is to continue doing research to determine how genetic testing using gene panels can help improve the diagnosis of genetic syndromes in this young population of patients.”

Patient and provider education about the increased incidence of colorectal cancer in younger patients is key to improving care, according to Andrea Cercek, MD.
Patient and provider education about the increased incidence of colorectal cancer in younger patients is key to improving care, according to Andrea Cercek, MD. “If the patient has symptoms that the provider might dismiss, like rectal bleeding, they should pursue it further with a colonoscopy as opposed to entertaining other ideologies and having to diagnose the cancer later on,” she said.

Photo courtesy of Memorial Sloan Kettering Cancer Center.

The identification of biomarkers also may help tailor treatments for this younger population, Andrea Cercek, MD, a medical oncologist at Memorial Sloan Kettering Cancer Center who has focused her research on biomarker identification to create molecular-based therapies for patients with metastatic colorectal cancer, told HemOnc Today.


“We first had to see if there is a distinct biology of these tumors, and we have an idea that there is,” Cercek said. “We have to identify biomarkers that drive these tumors, and then we have to ask if these are new hereditary factors that we didn’t know about or if there are other changes that are causing the cancer. Looking at the at-risk population would be the next step.”

Lieu also seeks to identify biomarkers that may play a role in treatment resistance.

Kopetz, Lieu and colleagues — in a study published in Journal of Clinical Oncology — identified changes during colorectal cancer treatment in plasma cytokines and angiogenic factors that appeared to predict resistance to 5-FU, irinotecan and bevacizumab (Avastin, Genentech). These included increased basic fibroblast growth factor (P = .046), hepatocyte growth factor (P = .046), placental growth factor (P < .001), stromal-derived factor-1 (P = .04) and macrophage chemoattractant protein-3 (P < .001) compared with baseline before the development of progressive disease.

Still, the identification of biomarkers remains in the investigative phase because researchers only recently learned that young patients do not respond as well to standard treatments, Lieu said.

During his fellowship at The University of Texas MD Anderson Cancer Center in 2008, Lieu was told that age was not a confounding factor in the treatment of colorectal cancer. The only differences were derived from anecdotal experiences.

“At the end of the fellowship, we started to ask if there could be a difference between younger and older patients,” Lieu said. “We were seeing more of these younger patients. In some instances they were being diagnosed young, and a couple of months later they would die and we were wondering, ‘What the heck just happened?’”

It was this increased incidence and the unexpected death of otherwise healthy, younger patients that spurred Lieu’s team to examine what might cause treatment resistance.

“I couldn’t provide the rationale to study the genetics or conduct mutational analyses of these younger patients with colorectal cancer until just recently,” Lieu said. “We got the data [to support these studies], and now we’re finally starting to look at the disease genetically.”

The role of screening

The identification of biomarkers in this at-risk population could trigger an evolution in the screening paradigm.

Current screening guidelines recommend commencing colonoscopy at age 50 years. Thus, screening individuals in their 20s and 30s would require a massive ideological shift, which could be outweighed by the associated costs and harms of screening.

Still, the lack of screening among younger individuals may directly contribute to the increased proportion of advanced-stage disease in this cohort.

“We are not only seeing more cancers in young people but we’re seeing them at a more advanced stage — and that is probably because we do not screen them,” Chang said. “Young patients also are diagnosed later because colorectal cancer is not on the forefront of their minds. If they see blood in their stool, for example, they are not thinking they should get a colonoscopy. Even their providers may not be thinking colon cancer. It takes longer to get the work-up needed and to make the diagnosis.”


The identification of biomarkers could help researchers isolate a group of younger individuals who may benefit from screening, leading to earlier identification of cancers in this cohort, Cercek said.

Meanwhile, patient and provider education regarding the increased incidence of colorectal cancer in younger patients is key to improving care, Cercek added.

“It is difficult to say that we should overreact to this increased incidence and screen people aged younger than 50 years with colonoscopies,” she said. “Population-wide, that’s probably not the right answer. But, we should increase the awareness among primary care providers and internists that there is an increased incidence of colorectal cancer in younger patients. If a patient has symptoms that the provider might dismiss, like rectal bleeding, they should pursue it further with a colonoscopy as opposed to entertaining other ideologies and having to diagnose the cancer later on.”

Although the time is not right to change screening guidelines, emerging affordable and effective screening approaches other than colonoscopy may be ideal screening methods for these younger patients, Zell said.

Fecal immunochemical testing (FIT) appears as accurate as colonoscopy for colorectal cancer detection, although it is not yet known whether FIT is as effective for prevention of colorectal cancer death, Zell said.

“The data we have so far indicate that it is an excellent test, and it is approved as a screening method for colorectal cancer by the American Cancer Society,” Zell said. “In the past, we’ve had three problems with colonoscopy screening — one, the cost; two, the number of providers is insufficient to screen the entire country; and three, it is a socially unacceptable screening method for many people. As a result, only approximately one-half of patients in the screening age are actually screened.”

Whether FIT, fecal occult blood testing or multitargeted DNA testing would be more accepted and cost-effective in a younger population is unknown, Zell added.

“These are the questions we need to start asking,” he said.

However, starting fecal occult blood testing at age 40 years “may not be the right thing to do,” Cercek said.

“Colonoscopy is the gold standard, but it should be preceded by some symptoms,” she said. “I wouldn’t recommend any other test because, if they were given and there were abnormalities discovered, they would be followed up with a colonoscopy anyway.”

However, the harms of screening may be magnified in this younger population, which still represents a small percentage of colorectal cancer cases, Boland said.

“We’re talking about a problem where, even though there is an increased incidence, it is still really uncommon,” Boland said. “Typically, people develop a test that is 90% specific. That means if you screen 100 people, 10 will have a false-positive test. Screening is not the answer. You cannot screen for a rare disease, and colon cancer is rare in young people.”

Research priorities

Metabolic causes of colorectal cancer, and providing support to younger patients with the disease, also are high-priority research areas.

Determining the cause of the increased incidence of colorectal cancer in younger adults is a crucial next step, Boland said.

“I don’t think a biomarker is going to help, because the false positives will be too high,” he said. “We have identified most of the high-penetrance colon cancer genes. In younger people, it is either a rare recessive disease, it’s not an autosomal-dominant disease, or it is autosomal dominant with really low penetrance. You have to do some dancing around to come up with a genetic explanation.”

Research should focus on understanding metabolic issues, Boland added.

“If you have extra fat on your body, it’s very metabolically active and it fosters inflammation in your gut and your blood vessels, and that is why these people have more cancers of all types and they have accelerated cardiovascular disease,” he said. “We need to go back to the drawing board ... and figure this out on a very basic level.”


Irrespective of the cause of the disease, more focus is needed on the support younger patients require, Lieu said.

“Regardless of the biology, the needs of young patients are different than those of older patients,” he said. “If you are 75 and retired and you develop colorectal cancer, the impact on your life is not necessarily worse or better, but it is certainly different than if you are a 30-year-old because of the impact on your career, education, family and kids. If you sit in a support group, there will be a bunch of 70-year-olds and one 30-year-old.”

A study by Sanford and colleagues —published in 2014 in Cancer — showed that among 718 patients with colorectal cancer, those who were younger appeared more likely than older patients to experience moderate or severe pain, fatigue, nausea, distress, drowsiness, shortness of breath and rash. They also reported greater interference with general activity, mood, work, relationships and life enjoyment.

“It is important to acknowledge that part of the problem is that the symptoms differ between younger and older adults, and that confuses physicians, patients and family members,” Zell said. “The good news is that 94% of young adults with colon cancer do have symptoms of colon cancer. The higher incidence is in left-sided tumors closer to the rectum, so they should be easier to find than those that are right sided.”

Understanding how these symptoms differ could improve the detection of colorectal cancer in younger patients.

“[The study by Sanford and colleagues provides] important insight into an area that we don’t know much about,” Zell said. “The symptoms of this disease are present but they may not be the classic symptoms — weight loss, constipation and anemia — that we look for in older adults. The more we learn about how younger patients present, the more we can increase early detection.” – by Anthony SanFilippo


Bailey CE, et al. JAMA Surg. 2015;doi:10.1001/jamasurg.2014.1756.

Kneuertz PJ, et al. JAMA Surg. 2015;doi:10.1001/jamasurg.2014.3572.

Kopetz S, et al. J Clin Oncol. 2009;doi:10.1200/JCO.2009.24.8252.

Lieu CH, et al. J Clin Oncol. 2014;doi:10.1200/JCO.2013.54.9329.

Meyer JE, et al. Cancer. 2010;doi:10.1002/cncr25432.

Mork ME, et al. J Clin Oncol. 2015;doi:10.1200/JCO.2015.61.4503.

Sanford SD, et al. Cancer. 2014;doi:10.1002/cncr.28297.

Singh KE, et al. J Adolesc Young Adult Oncol. 2014;doi:10.1089/jayao.2014.0006.

For more information:

C. Richard Boland, MD, can be reached at

Andrea Cercek, MD, can be reached at

George J. Chang, MD, MS, can be reached at

Christopher Lieu, MD, can be reached at

Eduardo Vilar-Sanchez, MD, PhD, can be reached at

Jason A. Zell, DO, MPH, can be reached at

Disclosure: Boland, Cercek, Chang, Lieu, Vilar-Sanchez and Zell report no relevant financial disclosures.



Are patients aged younger than 50 years with colorectal cancer overtreated?


Current evidence suggests young adults with colorectal cancer receive more aggressive treatments than older adults but do not benefit as much.

The question of overtreatment should be considered in the context of the balance between potential benefits vs. risks of the treatments. A diagnosis of colorectal cancer in a young adult often causes a very strong emotional and psychosocial response in the patient, the family, the treating physicians and other care providers. There is often a very natural and very strong desire to do everything we can, and administer the latest and most aggressive treatment regimens available on the market to these patients.

Yi-Qian Nancy You, MD, MHSc, FACS
Yi-Qian Nancy You

Fortunately, many young patients are healthy and are good candidates for these treatments. The key issue, however, is to remember that all treatments come at some cost of potential adverse effects and toxicities, and all treatment decisions involve a balance of benefits vs. risks.

Currently, a major gap in knowledge is our understanding of the mechanisms of carcinogenesis of colorectal cancers in young adults. We know that major hereditary colorectal cancer predisposition syndromes, such as Lynch syndrome and familial polyposis syndromes, account for only about 15% of these cases.


Therefore, in the remaining majority of the cases, unique interactions between genetic and environmental/lifestyle causes are undoubtedly responsible, but the exact genetic mutations and environmental/lifestyle risk factors have not been pinpointed to date. There is evidence that colorectal cancers in young adults do not benefit from the currently available treatments as well as other colorectal cancers.

We recently conducted a nationwide study that compared the treatments and outcomes of 13,102 young patients and 37,007 older patients with colon cancer. We found that for every stage of disease, young patients were two to four times more likely to receive intensive chemotherapy regimens after surgery.

However, these more intense treatments did not translate to more survival gain for young patients compared with their older counterparts. In fact, the survivals were largely similar.

In addition, other studies have shown that despite being enrolled in clinical trials where younger patients and other enrollees received the same trial-specified regimens, younger patients experienced increased risk for disease progression and death compared with older patients.

Taken together, current evidence seems to suggest that young adults with colorectal cancer receive more aggressive treatments but do not seem to benefit as much. In this sense, there is overtreatment for these young adults.

There are three important implications for moving forward. First, the 15% of the colorectal cancers that develop in young patients as a result of hereditary predisposition syndromes are potentially entirely preventable if one becomes aware of family history and are proactive about genetic testing, because active screening and surveillance starting at a young age could potentially prevent colorectal cancer development in these patients and families. Second, treatment decisions should be made considering the benefits vs. risks and more attention should be paid to sequelae of cancer treatments in young adults. Third, more research into the potentially unique carcinogenesis of colorectal cancer that arise at a young age is needed.



Kneuertz PJ, et al. JAMA Surg. 2015;doi:10.1001/jamasurg.2014.3572.

Yi-Qian Nancy You, MD, MHSc, FACS, is assistant professor in the department of surgical oncology in the division of surgery at The University of Texas MD Anderson Cancer Center. She can be reached at Disclosure: You reports no relevant financial disclosures.



In a nationwide cohort study, Kneuertz and colleagues found that younger patients aged 18 to 49 years received more intense treatment for all stages of colorectal cancer compared with older adults. More chemotherapy was associated with no survival gain for patients with stage II disease and only marginal improvements in survival for younger patients with stage III to stage IV disease. More is not always better, particularly for patients (of any age) with stage I or standard-risk stage II colorectal cancer.

Chloe Atreya, MD, PhD
Chloe Atreya

The story is more complicated for stage IV, metastatic colorectal cancer, and here I don’t think that we cannot conclude that younger patients are being overtreated. As the researchers point out, their data on patients with metastatic colorectal cancer must be interpreted with caution because only patients who received treatment with curative intent — including resection of their colon primary — were included in the analysis. It is also notable that younger adults presented with significantly more advanced stages of disease at diagnosis — if within-stage disease was also more advanced (eg, more nodal metastases or greater burden of distant metastatic disease), then more intensive chemotherapy may have closed what would otherwise have been a survival gap. Information on molecular features of prognostic and predictive import, such as RAS and BRAF mutational status and microsatellite instability, was not available.

The years 2003 to 2005 were chosen by the researchers “to reflect a period when treatments for colorectal cancer were consistent with current standards.” This may be true for early-stage and locally advanced colorectal cancer, but treatment has changed for metastatic colorectal cancer in the past decade. Although cetuximab (Erbitux, Lilly) was FDA approved in 2004, it was not until 2009 that treatment with EGFR-targeted antibodies was restricted to patients without known RAS mutations. More recently, FOLFOXIRI has made it into the National Comprehensive Cancer Network guidelines as an intensive induction therapy option for patients with good performance status (who are more likely to be younger) based on favorable results from the TRIBE study. Further, clinical trials for patient subsets with BRAF mutations, microsatellite instability and HER amplification are showing promising results. Younger patients with metastatic colorectal cancer have the advantage that they typically have fewer comorbidities and, therefore, I’m hopeful that the availability of more intensive, and perhaps more importantly, personalized therapeutic options is now paying off.



Kneuertz PJ, et al. JAMA Surg. 2015;doi:10.1001/jamasurg.2014.3572.

Loupakis F, et al. N Engl J Med. 2014;doi:10.1056/NEJMoa1403108.

Chloe Atreya, MD, PhD, is assistant clinical professor in the department of medicine at University of California, San Francisco, Helen Diller Family Comprehensive Cancer Center. She can be reached at Disclosure: Atreya reports no relevant financial disclosures.