Colorectal Cancer Screening and Surveillance in the Geriatric Population

Abstract

Purpose of the Review

Our national guidelines regarding screening and surveillance for colorectal cancer recommend individualized discussions with patients 75–85 years of age. This review explores the complex decision-making that surrounds these discussions.

Recent Findings

Despite updated guidelines for colorectal cancer screening and surveillance, the guidance for patients 75 years of age or older remains unchanged. Studies exploring the risks to colonoscopy in this population, patient preferences, life expectancy calculators and additional studies in the subpopulation of inflammatory bowel disease patients provide points of consideration to aid in individualized discussions.

Summary

The benefit-risk discussion for colorectal cancer screening in patients over 75 years old warrants further guidance to develop best practice. To craft more comprehensive recommendations, additional research with inclusion of such patients is needed.

Introduction

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in adults, with individuals 70 years and older representing more than 60% of all individuals with CRC [1, 2]. As the population of the United States is aging, and with gains in life expectancy, the percentage of individuals over age 75 years is projected to increase as well. In 2018, the percentage of the population over age 75 years was 6.7%; in 2060, that is expected to increase to 12.5% [3, 4]. Discussions surrounding CRC screening and surveillance colonoscopies for patients in this demographic are complex, and yet these are critical conversations to engage in. Currently, of patients 74 years and older, polyp surveillance was the most common indication for a colonoscopy. As a result, the number of surveillance colonoscopies is expected to reach 5.6 million per year by 2024 [5]. The risks of screening and surveillance colonoscopies should be weighed carefully and in the context of the potential benefits, as individualized conversations guide physician-patient shared decision making.

Current guidelines from the United States Preventative Services Task Force (USPSTF), the American College of Gastroenterology (ACG) and the American Cancer Society recommend individualizing screening for patients between 75 and 85 years of age [6–8]. These recommendations leave room for discussion as they take into consideration the uncertainty of benefits to CRC screening past age 75 years. Both the USPSTF and the American Cancer Society also recommend against CRC screening in patients over the age of 85 years [6, 8].

Topics to Guide Shared Decision Making

Risk of CRC

The chronological age of the patient must be considered in the context of overall patient health as well as benefits from screening. In a study of average risk adults undergoing screening colonoscopy, patients between 76 and 80 years had rates of advanced neoplasia and colorectal cancer that were twice as high as the rates reported in patients between 50 and 75 years of age [9]. Further, in a retrospective study of colonoscopies completed between 2010 and 2017 in the GI Quality Improvement Consortium database, patients over 75 years of age had a progressive increase in CRC rates and higher risk of advanced lesions [10]. However, a study by Lin et al. reported that the gains derived from screening, representing the mean time from polyp to the development of an advanced neoplasm, were 15% or less in older patients [11]. Similarly, Ko et al. found that the risk of screening related complications in patients between 70 and 94 years was higher than the estimated benefit in this same age group [12].

Risks of Colonoscopy

The risks of colonoscopy are largely related to bowel preparation, alteration in anticoagulation or antiplatelet medications pre-procedure, endoscopic evaluation including risks of bleeding and perforation, and procedural sedation.

Bowel preparations are associated with risks of volume depletion and electrolyte abnormalities. In particular, oral sodium phosphate and magnesium citrate, when used, have the potential to lead to renal complications. Dehydration and electrolyte imbalances in older adults can also predispose individuals to alterations in mental status and subsequent falls. In addition, many bowel preparation instructions include recommendations for split-dosing as this is associated with better clearance of stool. However, split-dosing instructions lead to overnight awakenings and is associated with an increased risk of sleep deprivation and falls. These aspects should be carefully considered in older adults [13]. This, in conjunction with overall functional status and baseline mobility, should help guide decisions not only regarding whether or not to pursue colonoscopy, but also for bowel preparation choice.

Older patients may also have difficulty completing bowel preparations, leading to inadequate visualization during colonoscopy. Inadequate bowel preparation leads to additional procedure time, which increases the risks of the procedure as well as the duration of sedation. Supporting this was a study of patients aged 80 years and older which found lower completion rates of colonoscopy in this group as a result of poor preparation. Moreover, 16% of patients age 80 years and older had inadequate bowel preparation [14].

Colonoscopy itself has complications of perforation, bleeding and peri-procedural cardiac and pulmonary complications. The American Society of Gastrointestinal Endoscopy, using a systematic review for average risk screening colonoscopies, found that the pooled event rate for serious adverse events was 2.8 per 1,000 procedures [15]. Overall, the pooled event rate of bleeding specifically was reported to be 8 per 10,000 colonoscopies while the pooled event rate of perforation was reported to be 4 per 10,000 colonoscopies. These rates have been found to increase with increasing age [16]. In patients 80 years of age or older, the reported risk of all-cause complications rises to 34.8 per 1,000 colonoscopies [17]. The reported risk of perforation was higher in patients 80 years of age or older when compared to patients 65 years or older [18]. Further, when evaluating post-colonoscopy complication rates in patients aged 50 to 74 years compared to those aged 75 years or older, the risk of complications was twice as high [19].

In older patients, procedural sedation can also lead to increased risk of hypoxia, aspiration, hypotension, and arrhythmias. As such, older patients may benefit from less procedural sedation, and this should be discussed on an individual basis. Slower infusion rates and the use of fewer sedative agents are two ways in which to accomplish this [20].

Finally, overdiagnosis is a risk that can also occur as a consequence of colorectal cancer screening. Overdiagnosis is the diagnosis and treatment of a cancer that would not have otherwise caused symptoms during the individual’s remaining lifetime. Although there is limited data on overdiagnosis in colorectal cancer screening, a review of autopsy data showed that 2–3% of individuals had undiagnosed and unrelated colorectal cancer at the time of death [21] (Table 1).

Table 1.

The Pros vs. Cons of CRC Screening and Surveillance in the Geriatric Population

Pros	Cons
Risk of CRC increases with age, and continued endoscopic evaluation will enable early detection and treatment of CRC	Increased risks of colonoscopy including:  - Colonoscopy prep-related risks  - Peri-procedure cardio-pulmonary risks  - Sedation risks  - Risks associated with changes in antiplatelets and anticoagulation  - Risks of colonoscopy itself including bleeding and perforation
Continued endoscopic evaluation may align more closely with individual patient preferences	Possibility of a poor-quality exam due to inadequate colonoscopy prep Overdiagnosis of CRC

Life Expectancy Calculators

Offering CRC screening to older adults comes with the intention that screening will lead to earlier detection, possible intervention, and improvement in overall quality of life. Ongoing endoscopic evaluation should be considered in all patients with a life expectancy of 10 years or more, as the benefits of a polypectomy will occur 7–10 years after the screening colonoscopy has occurred [22]. For the clinician and patient, estimating and conceptualizing life expectancy is oftentimes difficult. Tools that can add to the clinician’s judgment include the National Center for Health Statistics Life tables of the United States, though these tables do not consider an individual patient’s comorbidities or functional status [23]. Additionally, it would be important to consider an individual’s cognitive abilities to ensure that patients are able to engage in a shared decision-making discussion. As such, ePrognosis is a tool that does take into consideration a patient’s comorbidities and cognition and can be considered when weighing individual risks and benefits [24].

Such tools may also aid in discussions of when to stop CRC screening and surveillance. One study attempted to determine optimal ages to no longer pursue screening and found a range of ages. In this study, individuals with severe comorbidities should no longer undergo evaluation after 66 years of age, whereas previously unscreened women with no comorbid medical conditions should be offered screening up to 90 years of age [25]. The utilization and further development of tools including estimates of life expectancy, colorectal cancer risk, and prior screening, would aid in patient-physician discussions.

Patient Preferences

One of the most important factors when considering endoscopic evaluation among older adults is patient preference. Highlighting the importance of this was a study that included 1,388 endoscopies of the lower gastrointestinal tract among patients older than 80 years of age. In this study, CRC was diagnosed in 6% of patients, with eight refusing surgical treatment with the intent to cure [26]. As such, patient preferences for treatment following a positive screen and willingness to undergo therapy if cancer were to be diagnosed should be predetermined to help guide care. Those patients who would not tolerate or accept further invasive work-up or treatment may therefore not benefit from additional endoscopic evaluation.

Patients may also have strong preferences against screening cessation. A survey of veterans aged 50 years and older was conducted at the Veterans Affairs Ann Arbor Healthcare System between 2010 and 2012. This study found that 28.7% of respondents were not comfortable with cessation of CRC screening despite serious health problems or their physician’s recommendation that additional colonoscopies would not be of benefit. Furthermore, 49.3% of respondents thought age alone should not be used to decide screening cessation [27]. As one size does not fit all, this study highlights the importance of considering patient preference in addition to overall functional status as well as age and comorbidities when considering the decision to pursue further endoscopic evaluation (Table 2).

Table 2.

Summary Points

1. The risk of CRC increases with age as do the risks of procedural-related complications.

2. Additional research with inclusion of patients 75 years and older into RTCs will better establish the benefits of CRC screening and surveillance in this population

3. Comprehensive discussion regarding risks will assist in shared-decision making between physicians and patients > 75 years of age

4. Development of geriatric risk assessment calculators will aid in shared-decision making

Special Populations

CRC risk in patients with inflammatory bowel disease (IBD) remains higher than the general population. Paralleling the advancing age in the U.S. population, there also appears to be a growing prevalence of older adults with IBD. Despite this, there are no specific guidelines on the optimal times to stop CRC screening and/or surveillance in this subpopulation. In a study by Wintjens et al. of a Dutch cohort of patients diagnosed with IBD between 1991 and 2011, seven of 2801 patients were diagnosed with CRC at or over 75 years of age [28]. Additionally, in a multicenter cohort of 211 patients with UC over the age of 75 years, colonoscopy was found to have low yield if there was no prior evidence of dysplasia [29]. Analogous results were also seen in a study by Ten Hove Jr et al., in which IBD patients without additional risk factors for CRC and two consecutive negative colonoscopies had a low risk of advanced colorectal neoplasia [30]. These results however do not apply to the high-risk patient population with both IBD and PSC, with further data needed.

Additionally, the benefits of colonoscopy need to be weighed against the potential risks in the older IBD patient population. As data suggest accelerated biological aging in this patient population, there may be a higher risk of frailty, Alzheimer’s dementia, and comorbidities that may contribute to increased risks from colonoscopy preparation, endoscopy itself, and procedural sedation [31]. Further data is therefore needed to help guide these clinical decisions, allowing for a careful weight of both risks and benefits, as well as patient preferences.

Future Research

In order to advance the field of gastroenterology and update our current practices, there needs to be a greater inclusion of individuals 75 years of age and older in randomized controlled trials (RTC) of CRC screening and surveillance. Such research would provide additional data needed to help guide a comprehensive discussion surrounding risks, benefits, and patient preferences of a colonoscopy among older adults. Research on aging and IBD will also be valuable to provide guidance for those patients at higher risk of developing CRC. Such research would aid the formulation of future geriatric risk assessments that can be applied to both CRC screening and surveillance.

Conclusion

In conclusion, the complex decision-making that surrounds the recommendation of CRC screening and surveillance in the older adult population warrants further guidance. Although the risk of CRC increases with advancing age, the risks of endoscopic evaluation increase as well. Individualized recommendations for patients between 75 and 85 years of age should incorporate a knowledge of patient preferences in the context of such risks. These discussions should also make use of risk assessment tools that include life expectancy, prior endoscopic findings, comorbidities, and cognition, in order to provide a thorough exploration of risk.

With an expansion in CRC screening guidelines to begin at age 45 years old for an average-risk individual, and a limited number and capacity of endoscopists, the continued screening and surveillance of geriatric patients will likely impact our health care utilization. This is an important area for future research as the US population is aging and has the potential to significantly impact the landscape of gastroenterology.