Alexander M. Castellino, PhD
March 6, 2019
A comprehensive survey of patients and survivors of young-onset colorectal cancer (CRC) has revealed that the disease is often misdiagnosed in these patients, which may explain why the disease is often advanced when it is eventually diagnosed.
These survey findings were highlighted at a media preview ahead of the American Association of Cancer Research (AACR) 2019 Annual Meeting, to be held in Atlanta, Georgia, from March 29 to April 3.
Presenting the findings, Ronit Yarden, PhD, MHSA, director of medical affairs at the Colorectal Cancer Alliance, a patient advocacy organization, suggested that the diagnosis of CRC in any patient is difficult, owing to the fact that its symptoms, such as constipation, weight loss, and fatigue, are commonly seen with other conditions.
"Despite declining incidence in older adults, there has been a rapid and alarming rise in colorectal cancer incidence among young adults in recent decades," Yarden said in an AACR statement. "We do not yet know the cause of the rising incidence in younger patients, and there is little awareness of this trend among healthcare providers," she added. "Lack of awareness that CRC can occur in young patients appears to contribute to misdiagnosis," she said.
Colorectal cancer expert Alan P. Venook, MD, the University of California, San Francisco, Madden Family Distinguished Professor of Medical Oncology and Translational Research, who was not associated with this report, provided his own insights into the findings.
"The observations from the study are not surprising, and it is troubling that the absolute number of younger patients diagnosed with CRC is going up," Venook told Medscape Medical News.
However, Venook disagreed that a misdiagnosis or a delay in diagnosis correlates to the disease being found at a more advanced stage in younger patients.
"If patients are having symptoms, it is because they already have advanced disease, so it is not surprising that younger patients are more frequently diagnosed with advanced disease," he said.
The reason that early-stage disease is diagnosed in individuals older than 50 years is because of screening guidelines, which mostly recommend that screening begin at age 50. Colonoscopy picks up early disease in outwardly healthy adults who show no signs of the disease, he said.
Another observation was that the survey was conducted through social media and via the Colorectal Cancer Alliance website, which could have introduced a sampling bias and is a limitation of the study, Vernook commented.
"Only those who were social-media savvy could participate in the study," he said.
The intent of the survey, which was conducted by the Colorectal Cancer Alliance, was to capture information of clinical, psychosocial, financial, and quality-of-life experiences.
It was completed by 1195 persons. Of the respondents, 57% were diagnosed with CRC between the ages of 40 and 49 years, and 33% between the ages of 30 and 39. Only 8% of patients were diagnosed with Lynch syndrome.
The survey revealed that 71% of patients were diagnosed with late-stage disease (stage III or IV). This is in contrast to the observation from the American Cancer Association that CRC in older patients is diagnosed at an early stage.
The survey also found that 63% of patients and survivors waited for 3 to 12 months before visiting their physician because they were not aware that their symptoms were related to CRC.
Most patients indicated that they were initially misdiagnosed; 67% reported seeing at least two physicians, and some reported seeing more than four physicians, before a conclusive diagnosis of CRC was made. Misdiagnoses included hemorrhoids, irritable bowel disease, anemia, and diverticulitis.
"Young people need to be aware that colorectal cancer can happen at any age and it is not the disease of old people. Everybody should listen to their body, and if it doesn't feel right, go to the doctor to be tested," Yarden said in a statement.
Venook suggested that it does not occur to physicians to look for cancer in the young. "Cancer is typically a disease of older patients, so a misdiagnosis is not surprising," Venook said.
Moderator John D. Carpten, PhD, program chair of the AACR annual meeting and director of the Institute of Translational Genomics at the Keck School of Medicine, University of Southern California, Los Angeles, indicated that one of the important aspects of this research concerns its policy implications, because most current guidelines recommend screening for individuals older than 50 years.
Last year, the American Cancer Society lowered the starting age for CRC screening to 45 years, and a coalition of 22 public health and patient advocacy groups is campaigning for the US Preventive Services Task Force to also lower the starting age to 45 years, as previously reported by Medscape Medical News.
However, Venook told Medscape Medical News that he feels lowering the starting age by 5 years is not going to make much of a difference, because, increasingly, CRC is being diagnosed in even younger adults, those aged less than 40 years.
"The risk of colonoscopy is not trivial, and that is why it cannot be undertaken routinely outside guidelines," he added.
Venook also noted the need for novel screening tools that have greater specificity than colonoscopy.
The results from the third annual survey are currently available on the Coalition Cancer Alliance website. Yarden indicated that at the AACR meeting, additional insights and analyses will be provided.
The study was funded by the Colorectal Cancer Alliance. Yarden has disclosed no relevant financial relationships. Venook has consulted with Taiho Pharmaceutical, Bayer, Halozyme, and Eisai; has received research funding from Genentech/Roche and Bristol-Myers Squibb; royalties from Now-UptoDate for authoring and maintaining two chapters; and travel, accommodations, and/or other expenses from Genentech, Roche, Halozyme, and Bayer.
American Association of Cancer Research (AACR) 2019 Annual Meeting: Abstract 3347. To be presented April 2, 2019.