Background
Colorectal cancer (CRC) remains one of the most prevalent cancers worldwide and is one of the few cancers for which screening has been associated with better survival and morbidity outcomes.1
Much effort has been rightly put into understanding the barriers to screening uptake in average-risk age-eligible individuals, because screening rates remain generally suboptimal.2–4 Similarly in Singapore, despite considerable efforts being dedicated to promoting screening, a concerning trend is evident among eligible Singaporeans aged ≥50 years. Merely 27.3% participated in CRC screening, raising concern that screening participation among spouses of patients with CRC might be even lower.5 As such, upon turning 50 years of age, the Health Promotion Board (HPB) proactively sends mailers to notify individuals of their screening eligibility. Furthermore, because CRC screening is part of the national Screen for Life program for cancers and other chronic diseases in Singapore, eligible individuals are likely to have been provided information regarding CRC fecal immunochemical test (FIT) screening during their visits to primary care clinics across the country.
With these efforts in place, an underexplored subpopulation in screening uptake is spouses of existing patients with CRC. This is a potentially sizeable group; in the United States, for example, more than half (57.0%) of all patients with CRC in the national SEER registry diagnosed from 1975 to 2016 were married, accounting for some 299,390 spouses. Unfortunately, such data are unavailable in the context of Singapore, but the potentially large population highlights the need to turn our focus to this specific population. Although evidence is mixed on whether spouses of patients with CRC are actually at increased risk compared with the average-risk population due to shared lifestyle factors, our prior work has nonetheless suggested that screening uptake rates among spouses remains suboptimal (approximately 57.8%).6–8
Intuitively, such individuals should have greater knowledge of CRC and awareness of screening, and some studies have suggested that spouses may be more willing to undergo CRC screening.6,8–10 Extant research has also shown that barriers to screening uptake for spouses of patients with CRC are similar to those of the general age-eligible population, including inconvenience and cost of screening, lack of perceived susceptibility, and lack of recommendations from physicians and other health care providers.11–13
The primary objective of this study was to evaluate whether a brief, structured behavioral intervention delivered to spouses of patients with CRC in a colorectal clinical setting could increase FIT uptake (defined as completion of 2 FIT kits) within 3 months of the study period. We hypothesized that a significantly higher proportion of spouses who received the intervention would undertake CRC screening via FIT kit completion compared with the control group.
Methods
Ethical Approval and Study Protocol
This study was approved by the National Healthcare Group’s Domain Specific Review Board (DSRB 2017/00199). The study protocol was registered with ClinicalTrials.gov (identifier: NCT04544852) and reported in accordance with the EQUATOR Network’s CONSORT guidelines.14 All authors had access to the study data and read and approved the final manuscript.
Study Design and Setting
This study was designed as a block randomized, unblinded, parallel trial (1:1 ratio) conducted in the colorectal outpatient clinics of the National University Hospital and the Ng Teng Fong General Hospital, Singapore. All participants were prospectively recruited in-person from the patient waiting areas of the 2 aforementioned clinics from December 2017 through February 2023.
Eligibility Criteria
Participants were recruited if they (1) had a spouse/partner diagnosed and treated for CRC, (2) met the eligibility for screening as part of the national CRC screening program (ie, Singaporean or Singapore permanent resident; age ≥50 years; had not completed a FIT kit in the past 12 months [ie, non–screen-current]; and had not completed a colonoscopy in the past 10 years), and (3) were cognitively able to provide informed consent.
The exclusion criteria were (1) preexisting family history of familial adenomatous polyposis (FAP), hereditary nonpolyposis CRC (HNPCC), or inflammatory bowel disease, and (2) previous personal medical history of CRC or colorectal polyps.
Intervention and Control Groups
Participants in both groups received a structured informational pamphlet on CRC screening from the Singapore Ministry of Health and were also given a single instructional face-to-face session with the study team, which emphasized the local prevalence of CRC and participants’ age eligibility for CRC screening based on the national screening program. This session typically lasted approximately 10 minutes. This was done to ensure that there was a standardized baseline level of screening awareness in both study groups using existing information, which can be found online. The participants in the control group were then informed by the study team that they were eligible for screening based on their age eligibility and that they could obtain 2 FIT kits from various distribution partners (such as retail pharmacies and polyclinics) as part of the national CRC screening program.
On the other hand, participants in the intervention group were additionally provided with a printed guide with instructions on how to properly use a FIT kit (see the Appendix in the supplementary materials, available online with this article), provided with 2 FIT kits, and given a prepaid return envelope to return the completed kits. Completed FIT kits from the intervention group were sent to a partnering laboratory replicating the operational protocol used by the national screening program.
Participants from both groups were followed up 3 months after recruitment to determine if they had completed FIT screening.
Primary Outcome
The main outcome of interest in this study was CRC screening uptake, defined as having 2 FIT kits completed and returned to the study team and/or self-reported completion of 2 FIT kits, within 3 months after recruitment.
Sample Size Determination
Sample size was calculated using power calculations based on existing CRC FIT screening uptake in the Singapore general population (approximately 27.0%) and with reference to existing literature on the efficacy of structured behavioral interventions in improving CRC screening uptake (mean effect size, 28.0%; range, 15.0%–50.0%).5,15–18 With a 2-sided alpha level of 5.0% and power of 80.0%, a target sample size of 45 participants per group was anticipated (90 participants in total).
Interim Analyses and Trial Stoppage
One interim analysis was performed during the trial, using the Haybittle–Peto stopping boundary of critical value >3 and P<.001 for between-groups analysis of the primary outcome.19 This permitted us to stop the trial for early effects at a sample size of 60 participants (29 intervention, 31 control).
Randomization of Sample
We used an online randomization generator to generate a 1:1 allocation list with block size of 4. To mitigate possible bias, group allocation for each participant was concealed in sealed envelopes by a member of the study team not involved in the recruitment process. Each individual envelope was numbered with predetermined participant IDs. After successful recruitment, the appropriately numbered envelope was opened by the study team member who recruited the participant and the group allocation was recorded accordingly in the dataset. Due to the nature of the behavioral intervention, blinding was not possible within the context of this trial.
Statistical Analyses
All statistical analysis was performed using Stata/BE 17.0 (StataCorp LLC). Baseline sociodemographic characteristics were presented using descriptive analyses. Bivariate chi-square tests of association were used for between-groups comparison of categorical baseline variables, and independent samples t test was used to compare mean age between the intervention and control groups. The primary outcome in this trial was uptake of 2 FIT kits within 3 months after recruitment. The chi-square test of association was used to compare the primary outcome between the intervention and control groups. Statistical significance was defined as P<.05 for all final analyses.
Patient and Public Involvement
Patients were not involved in the design, conduct, or analysis of the present research. However, should this intervention be considered for implementation in the participating sites, patients and their spouses will be approached as part of institutional quality improvement initiatives in stakeholder engagement.
Results
A total of 60 spouses of patients with CRC were analyzed for this study, with a median age of 62 years (range, 50–80 years); 29 participants were randomized to the intervention group and 31 to the control group. The process of enrollment is illustrated in Figure 1.
CONSORT flow diagram of participant recruitment, allocation, follow-up, and analysis.
Abbreviations: FIT, fecal immunochemical test; PR, Singapore permanent resident; SG, Singaporean.
Citation: Journal of the National Comprehensive Cancer Network 22, 6; 10.6004/jnccn.2024.7018
Baseline Characteristics of the Sample
No significant differences in demographic characteristics were observed between the 2 groups. A detailed breakdown of the demographic characteristics of recruited participants can be seen in Table 1.
Demographic Characteristics of Spouses of Patients With Colorectal Cancer
Between-Group Differences in FIT Uptake Within 3 Months
Overall, there was a statistically significant difference (P<.001) in FIT screening uptake between spouses in each group, with 86.2% (n=25) in the intervention group and 38.7% (n=12) in the control group. As such, the effect size for FIT screening uptake rate was 47.5 among spouses of patients with CRC. The screening behaviors in the intervention and control groups are reported in Table 2.
Between-Group Differences in FIT Uptake Within 3 Months
Discussion
The objective of this study was to establish the efficacy of a structured behavioral intervention in encouraging spouses to undergo screening via a FIT kit, as per the efforts of the Singapore national CRC screening program. To our knowledge, this was the first randomized trial specifically targeting screening uptake in spouses of patients with CRC, as opposed to behavioral interventions for average-risk individuals or couples in the general population.
Our study suggests that a simple structured intervention can be efficacious in greatly improving the chances of FIT uptake among non–screen-current spouses of patients with CRC. Significantly, screening uptake in the control group (38.7%) was already higher than in the general population. This was somewhat unsurprising, because the study sample could realistically be expected to possess a baseline awareness of CRC and the benefits of screening for early detection. Our intervention approach and materials were also atheoretical, focusing instead on increasing awareness of CRC and CRC screening as well as convenience by providing FIT kits rather than having spouses self-collect as per the current national screening program. However, the findings were consistent with extant literature emphasizing the importance of cues to action (eg, physician recommendations, peer and familial influence) as a facilitator in encouraging individuals to perform health screening; based on existing behavioral theories such as the health belief model, it is possible that this simple cue of giving out FIT kits could have been influential in encouraging intervention group participants to undertake screening. Nonetheless, our study context highlights the potentially high yield of implementing actionable cues in a population that is not naïve to CRC and understands the benefits of screening and their own susceptibility to cancer.11,20,21
From a health services standpoint, our study represents a proof-of-concept for promoting CRC screening in tertiary settings in addition to through existing lay public and primary care initiatives. The target population is not large; a total of 11,689 incident CRCs were diagnosed locally from 2015 through 2019.22 Applying rough estimates of the national average that 61.8% of Singaporeans are married suggests there are approximately 7,224 spouses of patients with CRC, of which 2,796 (38.7%) would be screen-current, resulting in a potential cohort of only 4,428 eligible spouses (over 5 years) who are likely screen-naïve or noncompliant with national screening recommendations.23 Nonetheless, spouses of patients with CRC represent a receptive but untapped audience for clinicians to access, because they are usually the primary informal caregiver and will co-journey with the patient through the various consultations and treatment milestones.24 Considering the relatively low time cost and logistical complexity, it may be a wasted opportunity to not promote FIT screening to non–screen-current spouses of patients with CRC within the tertiary colorectal clinic setting. Practically speaking, this would entail further pragmatic trials or institutional quality improvement initiatives, potentially across multiple sites, to determine the generalizability of findings and establish the cost-effectiveness of upscaling such an intervention.
Taking a more macro public health perspective, CRC is likely to remain one of the most incident and prevalent cancers globally, especially in the face of rapidly ageing populations in the developed world, even as screening uptake rates remain suboptimal. We argue that the way forward should involve engaging screening-eligible populations using an opportunistic whole-of-society approach that goes beyond “traditional” modalities of health promotion.25 Instead of only attempting to bring individuals to CRC screening, this study suggests the potential benefits of taking advantage of key facilitators (external cues, convenience) to bring CRC screening to individuals.11,26 For example, patients with CRC are willing to promote CRC screening to their loved ones, although our prior research cautioned that such efforts should only be used as adjuncts to other formal programs.27 Similarly, it may be useful to establish the feasibility of engaging spouses of patients with CRC as potential screening advocates, given their relatively high awareness of the significance of CRC and associated preventive measures.
Limitations
This study is not without its limitations. It is important to acknowledge the potential for selection bias due to the recruitment approach used. Although we approached all patients with CRC and asked for their marital status, it was extremely challenging to recruit spouses who did not accompany the patient due to reasons such as having a busy schedule. This might have introduced a bias and restricted the representativeness of our sample to a subset of spouses who are actively involved in supporting their partners throughout the CRC journey. Thus, the study sample may not fully represent the entire population of spouses of patients with CRC. Additionally, we acknowledge the potential risk of spurious findings due to the decision to stop the trial at interim analysis. There might also have been a missed opportunity to potentially perform any subgroup analyses with a larger sample. However, the Haybittle–Peto stoppage rule was invoked by the study team due to practical and logistical reasons relating to the difficulty of consenting eligible participants. Nonetheless, as per the principles of the Haybittle–Peto boundary, it is likely that a significant main effect would still have been observed if the trial had been continued.19
Conclusions
This study demonstrated that a brief, structured behavioral intervention offered to spouses accompanying patients with CRC while they wait for the clinic appointment is useful in increasing FIT screening uptake rates. The short intervention provided education about the significance of CRC, CRC screening, and the convenience of screening, which are often key barriers to screening uptake. Colorectal clinics can consider setting aside 10 to 15 minutes to educate accompanying spouses of patients with CRC in the future as a complementary avenue to holistically promote CRC prevention. Perhaps, even with the lack of resources to provide one-to-one counseling with the spouses, simply giving out a pair of FIT kits can result in a moderate increase in spouses completing screening. Future studies are necessary to determine the scalability and replicability of our findings, as well as to consider the possibility of using spouses as advocates of CRC prevention to other at-risk loved ones, such as siblings and adult children of the patient.
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