Endoscopy before age 50 years linked to reduced risk for colorectal cancer among women

Disclosures: Chan reports grants from Pfizer; personal fees from Bayer Pharma AG, Boehringer Ingelheim and Pfizer; and a Stuart and Suzanne Steele Massachusetts General Hospital Research Scholar award outside the submitted work. Please see the study for all other authors’ relevant financial disclosures. Calip reports stock ownership in Roche and grants from Pfizer outside the submitted work. Meropol reports equity ownership in Flatiron Health and stock ownership in Roche outside the submitted work. Weinberg reports no relevant financial disclosures.

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Women who initiated endoscopy screening before age 50 years demonstrated a significantly reduced risk for colorectal cancer than women who did not undergo endoscopy, according to study results published in JAMA Oncology.

Additionally, women in whom endoscopy had been initiated between ages 45 and 49 years had a greater decrease in the total number of colorectal cancer cases through age 60 years, researchers noted.

Hazard ratios for colorectal cancer risk.
Data derived from Ma W, et al. JAMA Oncol. 2022; doi:10.1001/jamaoncol.2022.0883.

Rationale and methods

colorectal cancer is associated with significant morbidity and mortality in the United States. The overall incidence of colorectal cancer has decreased in recent decades but there has been a steady and unexplained increase among individuals younger than 50 years,” Andrew T. Chan, MD, MPH, chief of the clinical and translational epidemiology unit at Massachusetts General Hospital, told Healio.

Previously, routine screening for colorectal cancer had been recommended for average-risk individuals after age 50 years, but American Cancer Society and the US Preventive Services Task Force updated their guidelines within the past 4 years and recommended screening initiation at age 45 years for individuals at average risk, Chan added.

Andrew T. Chan, MD, MPH

Andrew T. Chan

“This recommendation was based on benefit vs. burden estimated by comparative modeling approaches using microsimulation models for colorectal cancer screening in a hypothetical cohort,” he said. “Colonoscopy or sigmoidoscopy are important screening methods by removing precancerous lesions or detection of early-stage cancers. However, little empirical data are available regarding the effectiveness of endoscopic screening in younger populations.”

For this reason, Chan and colleagues sought to assess the association between endoscopy initiation at different ages and risk for colorectal cancer between August 2020 and June 2021 among 111,801 US women aged 26 to 46 at enrollment (median age, 36 years) included in the Nurses ‘ Health Study II. Researchers estimated cumulative incidence of colorectal cancer in each group with age as the time scale and measured the absolute risk reduction associated with endoscopy initiation at different ages through age 60 years.

Incident colorectal cancer served as the primary outcome, confirmed by medical records, pathology reports and the National Death Index.

Key findings

Researchers identified 519 incident colorectal cancer cases within 26 years, which corresponded to 2,509,358 person-years of follow-up.

Results of multivariable analysis showed women who underwent endoscopy vs. no endoscopy had a significantly lower risk for incident colorectal cancer for age at initiation before 45 years (HR = 0.37; 95% CI, 0.26-0.53), between 45 and 49 years (HR = 0.43; 95% CI, 0.29-0.62) , 50 to 54 years (HR = 0.47; 95% CI, 0.35-0.62) and 55 years and older (HR = 0.46; 95% CI, 0.3-0.69).

Moreover, researchers found an absolute reduction in the estimated cumulative incidence of colorectal cancer through age 60 years of 72 per 100,000 persons for initiation of endoscopy between ages 45 to 49 years compared with 50 to 54 years.

Women who initiated endoscopy before age 50 years also experienced a reduction in colorectal cancer risk diagnosed prior to age 55 years (before age 45 years, HR = 0.45; 95% CI 0.29-0.7; 45 to 49 years, HR = 0.43; 95% CI, 0.24-0.76).


“Our findings support recent guidelines that recommend screening for colorectal cancer at age 45 years and provide empirical evidence for patients, physicians and policymakers to consider when making decisions about colorectal cancer screening in a younger population,” Chan said.

Additional research is needed to assess the potential impact of initiating screening at an earlier age with noninvasive modalities, including fecal immunochemical testing or fecal DNA tests, he added.

“Our cohort included only women, therefore, studies in other populations are needed considering potential gender differences and racial and ethnic disparities in colorectal cancer risk,” Chan said.

Although these findings suggest an association of endoscopy with colorectal cancer prevention among white women younger than 50 years, the potential public health impact of revised screening recommendations is still not fully understood, according to an accompanying editorial by Gregory S. Calip, PharmD, MPH, PhD, associate professor in the department of pharmacy systems, outcomes and policy at University of Illinois Cancer Center’s College of Pharmacy; Neal J. Meropol, MD, medical oncologist and vice president of research oncology at Flatiron Health; and David S. Weinberg, MD, MSc, chair of the department of medicine at Fox Chase Cancer Center.

“Putting aside the nuanced balance of the immediate risks and long-term benefits of screening endoscopy for colorectal cancer, more concerted colorectal cancer prevention efforts are needed for all age groups,” they wrote. “With the existing colorectal cancer screening recommendations now in place for individuals aged 45 years or older at average risk for colorectal cancer, other critical questions as to the real-world comparative effectiveness, uptake and adherence to different forms of colorectal cancer screening in younger individuals deserve attention and further research.”


Calip GS, et al. JAMA Oncol. 2022; doi:10.1001/jamaoncol.2022.0863.
Ma W, et al. JAMA Oncol. 2022; doi:10.1001/jamaoncol.2022.0883.

For more information:

Andrew T. Chan, MD, MPH, can be reached at Massachusetts General Hospital, 100 Cambridge St., Boston, MA 02114; email: achan@mgh.harvard.edu.

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