Background
Enhancing work participation of cancer survivors has gained more attention in the past few decades [
1,
2]. This has been necessary, since almost half of persons diagnosed with cancer are of working age, and survival rates have continued to increase [
3,
4]. Work is part of cancer survivors’ identity, and contributes to their well-being [
5,
6]. Work can also be a well-appreciated distraction and provide an opportunity to stay socially active during treatments, to regain a sense of normality, and to earn a living [
6]. Despite the attention paid to enhancing cancer survivors’ work participation, a significant proportion still have to deal with short and long-term adverse work outcomes due to their cancer, such as unemployment [
7‐
10].
So far, most work-related interventions have focused on the cancer survivors themselves; for example, by means of education, counselling, or physical training [
11,
12]. These interventions have shown inconclusive results on survivors’ work outcomes [
11,
12]. This might argue in favour of shifting the focus to other stakeholders, such as occupational physicians and employers. Adequate support from the workplace is regarded as vital, and employer support has been found to be key in facilitating cancer survivors’ return to work [
13]. By “employer”, we here mean the specific person who represents the organisation that employs the cancer survivor, supporting them during their sickness absence and RTW; for example, the supervisor, line-manager or human resources manager (HR manager). Employers themselves point out that providing RTW support to cancer survivors is challenging, at best [
14‐
17]. Employers experience complex communication and decision-making dilemmas; for example, because survivor and organisational interests may contradict [
16,
17]. Numerous studies have therefore emphasised the need for interventions targeted at employers, to improve their support for cancer survivors [
11,
15‐
21]. As such, cancer survivors’ work outcomes may be enhanced via the employer.
We have developed such an employer-based intervention, named MiLES (an abbreviation of “the Missing Link: optimising return to work of Employees diagnosed with cancer, by Supporting employers”) [
22]. This includes information, videos, and checklists to support employers in providing adequate RTW guidance when one of their employees is diagnosed with cancer. As a “one-sized-fits-all” approach will not meet the needs of every employer or survivor [
23,
24], the MiLES intervention differentiates between 4 RTW phases (i.e. disclosure of cancer to the employer, treatment of the cancer survivor, RTW planning, and actual RTW). In addition, various experience types of cancer survivor are distinguished [
25] and the content of the intervention is tailored to these experience types [
22]. By providing employers with support so as to improve their RTW guidance to cancer survivors, the MiLES intervention aims to enhance successful RTW of cancer survivors [
22].
In a previous study, we have assessed the use and perceived usefulness of the MiLES intervention among employers [
26]. We found that most employers (
n = 22; 82%) used the intervention, typically 2–3 times over a period of 6 weeks, and on average for 26 min per visit [
26]. Employers perceived the intervention to be useful (i.e. perceived usefulness was scored 7.6 out of 10 points), and all participated employers would recommend the intervention to colleagues [
26]. These results clearly show that, from the employer perspective, the MiLES intervention is a useful tool that is suitable to employers’ daily practice. The question of whether the MiLES intervention is actually effective in enhancing the successful RTW of cancer survivors, is unanswered. Knowledge on its effectiveness on cancer survivors’ work outcomes is urgently needed, so that cancer survivors and their employers can benefit from the MiLES intervention, when effectiveness has been proven.
Tools that intervene at the intersection between employer and cancer survivor are scarce [
27,
28], and studies to determine the effectiveness of such tools on survivors’ work outcomes are, to the best of our knowledge, absent in scientific literature [
19,
27,
28]. Various aspects complicate studying the effectiveness of an employer-based intervention on work outcomes of cancer survivors. For example, outcomes are measured in a different population (i.e. cancer survivors) than the population whose behaviour is intended to be changed by means of the intervention (i.e. employers). Combining these 2 layers in 1 study is impeded by ethical concerns and privacy regulations [
29]. Including employer-employed survivor pairs is not allowed as it breaches privacy regulations concerning the exchange of health-related information between these 2 parties [
29]. As a consequence, the measurement of variables by either side (e.g. work outcomes of the cancer survivors and their respective employers’ user data concerning the intervention) is also not possible, obviating the conduct of per-protocol analyses. Besides such complicating aspects, it is also uncertain whether cancer survivors are willing to participate in a study on the effectiveness of an intervention targeted at their employer. Taking these complicating aspects and uncertainties into consideration, it is essential to conduct a feasibility trial before conducting a future definitive trial on the effectiveness of the MiLES intervention on successful RTW of cancer survivors [
30,
31]. For this, a so called “randomised feasibility study” is appropriate, since this type of feasibility study reflects the future definitive randomised controlled trial (RCT) on most parts, including randomisation [
32]. By running the “smaller version of the future definitive RCT” a randomised feasibility trial can thus uncover obstacles for such a future definitive RCT, and thereby increase the probability that it will be successful. Or it can prevent a costly but unfeasible study being carried out [
30,
33,
34].
The aim of this randomised feasibility trial was to assess feasibility of a future definitive RCT on the effectiveness of the MiLES intervention in terms of recruitment, reach, and acceptability of the study protocol. Secondary aims were: 1) to obtain preliminary results on the effectiveness of the MiLES intervention on successful RTW of cancer survivors, and 2) to determine the sample size needed in a future definitive RCT on the effectiveness of the MiLES intervention.
Methods
The CONSORT 2010 extension for randomised pilot and feasibility trials was used to structure the reporting of this study [
34]. This extension was developed based on the standard CONSORT checklist for RCTs, with some items being removed and some items specifically related to feasibility trials being supplemented, such as items on the reporting of prespecified criteria used to judge whether or not to proceed with a future definitive RCT [
35]. The completed CONSORT checklist (retrieved from
www.consort-statement.org) can be found in Additional file
1. The study has been registered in the Dutch Trial Register (NTR) (
www.trialregister.nl; registration numbers NL6758 and NTR7627, dd. 30/10/2018). The objectives, development, and design of the MiLES intervention [
22], as well as the study design [
36] have already been described in detail elsewhere. The study protocol can also be found in Additional file
2. No significant changes were made with regard to the published design.
Trial design
The study was conducted as a non-blinded randomised feasibility trial with a follow-up of 6 months. Eligible employed cancer survivors were randomised to an intervention group, in which cancer survivors were encouraged to inform their employer about the MiLES intervention, or a waiting-list control group, with the employer of the participating survivor not receiving the intervention for a period of 6 months. Participating cancer survivors filled in an online questionnaire at baseline, and at 3 and 6 months into follow-up.
Participants
Based on feasibility-study size estimations [
31,
33], we aimed to include 90 cancer survivors who met the following inclusion criteria: between 18 and 63 years of age; diagnosed with cancer < 2 years earlier; in paid employment under a temporary (> 6 months remaining) or permanent contract on a full-time, part-time, or flexible basis; currently fully or partially sick-listed for < 1 year; able to complete 3 questionnaires in the following 6 months (as assessed by their medical specialist on the basis of their current health and expectations about their health in the future); and able to understand, speak, and read Dutch sufficiently to fill out the questionnaires. We excluded cancer survivors who had not informed their employer about their diagnosis of cancer, in order to not to put them under unintended pressure to make that disclosure through the procedures of this study.
Potential eligible cancer survivors were recruited via medical specialists at 2 hospitals in the Netherlands. Cancer survivors received an invitation letter, information sheet, approach form, and return envelope, and were asked to indicate on the approach form whether they met the inclusion criteria and whether or not they were interested in participating. At 1 hospital, postal reminders were sent out 3 weeks after the invitation to those survivors who had not yet returned the approach form. In the event that a survivor indicated that they were interested in participating, MG or the research assistant contacted them to explain the study and to check their individual eligibility. Survivors were included after signing a digital informed consent form.
In addition to that outlined above, which has been described in the published design [
36], we employed 3 additional recruitment strategies: open invitations distributed at drop-in centres for cancer survivors; a link on social media (Facebook and LinkedIn); and open invitations and a link in newsletters sent by Dutch cancer-related websites, such as the online platform
www.kanker.nl. In response to all these recruitment strategies, cancer survivors who were eligible and interested in participating could sent a postal or digital approach form to the research team, after which MG or the research assistant contacted the respondent by telephone to check the their eligibility and, if they were indeed found to qualify, to include them in the study.
Interventions
The MiLES intervention targeted at the participant’s employer
The MiLES intervention was developed using the comprehensive and systematic Intervention Mapping approach [
22,
37], and consists of an online toolbox targeted at the participant’s employer. An extensive overview of the development, objectives and various components of this toolbox has been published elsewhere [
22]. In short, a needs assessment was developed with input from, among others, employer interviews (
N = 30) [
16], a systematic review [
23], and a Delphi study [
24]. The toolbox targets the most important employer actions for successful RTW selected by employers and cancer survivors [
22,
24]. The Resource Dependence Institutional Cooperation (RDIC) model was used [
23,
38], which assumes that whether an employer performs a specific employer action properly is determined by their willingness and their ability to support. It was assumed that support from the employer will be adequate if the employer is willing and able to perform the most important employer actions and to tailor these actions based on the preferences and needs of their specific cancer survivor [
22]. Additionally, the trans-theoretical model of change was used as a theoretical framework for making changes, and several methodologies were employed to induce the desired behaviour change, for example modelling, goal setting, tailoring, active learning and scenario-based risk evaluation [
22]. The toolbox was develop as a web-based intervention with succinct information, interactive communication videos, conversation checklists, and links to reliable external sources [
22]. The content of the toolbox is tailored per RTW phase and per cancer survivor experience type. For the latter, 3 predefined types are distinguished [
25]: 1) an
emotional cancer survivor, in which intense emotions such as sadness and anger can alternate quickly; 2) a
cancer survivor who wants little attention for their health situation, and wants to be involved in work for as long as possible and return to work as quickly as possible; and 3) a
cancer survivor who starts looking differently at work and life, and gives other priorities due to their illness. Employers who used the toolbox have indicated that it increased both their ability and their willingness to support cancer survivors (94 and 66% of the participated employers, respectively) [
26]. The toolbox is accessible via an URL that was not traceable using any online search engine throughout the study period; this was to prevent employers of participants in the control group being exposed to the intervention.
Intervention group
Participants randomised to the intervention were asked to inform their employer about the online toolbox, either by e-mail with attached secured PDF or by printed letter (both supplied by the research team). The PDF and letter complied fully with privacy and security regulations, and contained information about the participant’s involvement in the study, the URL of the toolbox, and a short promotional video to persuade the employer to visit the toolbox. The employer was asked to watch the video and to use the online toolbox during the participant’s sick leave and RTW. A comparable method to inform employers about the online toolbox, i.e. a one-off provision of the URL of the toolbox, has previously led to a reasonable use of it: 82% of the participating employers used the toolbox, typically 2–3 times over a period of 6 weeks, and on average for 26 min per visit [
26].
Control group
Participants randomised to the control group were not able to inform their employer about the online toolbox for a period of 6 months. Consequently, they received “care as usual” from their employer. After this follow-up period of 6 months, they were able to inform their employer about the online toolbox, using the same materials as the intervention group.
Outcomes
Data was collected using the electronic data-capture system Castor [
39]. Participants received an invitation to fill out the questionnaires at baseline (T0, before randomisation), and at 3 and 6 months into follow-up (T1 and T2, respectively). In the event that a participant failed to complete 1 of the questionnaires, a reminder was sent by e-mail after 1 week and a telephone call made to them after 2 weeks.
Participant characteristics
The T0 questionnaire included questions about the participant’s sociodemographics (i.e. age, gender), health (i.e. diagnosis, treatment, and experience type, based on 3 predefined types [
25]) and work (i.e. position, workload, size and sector of the organisation, and duration of sick leave). All questionnaires collected information on the participant’s involvement in any co-interventions, the number of contact moments with their employer since diagnosis (in T0) or in the previous 3 months (in T1 and T2), and their RTW phase.
Feasibility of a future definitive RCT
The following method and protocol-related measures were tracked to study feasibility of a future definitive RCT [
31,
40]:
reach (number of potential eligible cancer survivors who received an invitation to participate in the study),
appropriateness of inclusion criteria (number of potential eligible survivors not able to participate because of each inclusion criteria),
recruitment rate (percentage of potential eligible survivors included), and
retention rate (percentage of participants not lost to follow-up). The
appropriateness of the study protocol was determined on the basis of the percentage of participants who dropped out due to the randomisation procedures or due to randomisation in the control group (
appropriateness of randomisation procedures), and the percentage of participants who dropped out due to the procedures related to informing their employer, as well as the percentage of participants in the intervention group who did not inform their employer about the online toolbox (
appropriateness of procedures of informing the employer) [
40].
Effect measures
Measures for preliminary effect evaluation were collected at each time point (i.e. T0, T1 and T2). The primary effect measure was ‘successful RTW’, which is a combination of 2 components:
1) RTW, which all participants were asked about. Specifically, ‘Have you performed any work activities in the past 4 weeks? This can be either your own original work activities or adapted work activities replacing your original work’ [yes/no].
2) The degree of success of RTW (if returned), measured using the Successful Return-To-Work questionnaire for Cancer Survivors (I-RTW_CS) [
41]. This covers 7 items deemed to constitute successful RTW, measuring how the participant perceives their importance and successful accomplishment. Each item’s success score [1–6 rating scale] is weighted by its perceived importance [1–5 rating scale] by multiplying the success and importance scores, which results in that item’s weighted score. The sum of all items’ weighted scores divided by the sum of all their importance scores is the final I-RTW-CS score [range: 1–6]. This ensures that the more important a person perceives an item to be, the larger the contribution it makes to their I-RTW_CS score [
41].
Secondary effect measures were:
1) The Quality of Working Life Questionnaire for Cancer Survivors (QWLQ-CS) [
42]. This measure is about survivors’ experiences and perceptions in the work environment in the previous 4 weeks, and thus was only completed by the subgroup of participants who did return to work.
2) Unwanted work changes since diagnosis (at T0) and in the previous 3 months (at T1 and T2).
Randomisation
The electronic data-capture system Castor was used to randomise participants into the intervention or control group [
39], with the allocation ratio set at 2:1. This ratio was chosen to include a larger sample in the intervention group and thereby provide more information on the feasibility criteria of the study design. Randomisation was controlled for the participant’s RTW status, i.e. having performed work activities in their own or substitute work during the previous 4 weeks (yes versus no), since it is not possible to evaluate the effect on successful RTW reliably when RTW itself (which is a prerequisite for successful RTW) is unequally distributed over the 2 groups at baseline. Neither the participant nor the research team was blinded for the randomisation.
Statistical methods
All data was analysed using SPSS 24.0 (IBM, NY, USA). Data entry and analyses were double checked. Data was analysed according to the intention-to-treat principle. All participant characteristics, feasibility data and data for the effect evaluation were assessed using descriptive statistics. P-values < 0.05 were considered statistically significant.
Feasibility of a future definitive RCT
In the absence of guidelines for assessing feasibility of a future definitive RCT, we formulated the main uncertainties concerning the feasibility of studying the effectiveness of the MiLES intervention in such a future definitive RCT, and specified criteria for each of these uncertainties:
1) Criterion for appropriateness of inclusion criteria and for recruitment: ≥ 70% of the individuals who gave permission for telephone contact are willing to participate in the study;
2) Criterion for appropriateness of protocol: ≤ 20% do not want to participate due to the randomisation procedure or are lost to follow-up due to randomisation in the control group;
3) Criterion for appropriateness protocol: ≤ 20% of the participants are not willing to inform their employer about the online toolbox after randomisation into the intervention group;
4) Criterion for retention rate: ≤ 20% of the participants are lost to follow-up; and,
5) Criterion for reach: the sample size number of 90 participants is included within the recruitment period of 6 months, starting when the first individual is invited by their treating physician.
A future definitive RCT to study the effectiveness of the MiLES intervention was considered feasible when all of these criteria were met. If not, adjustments for the study protocol were formulated.
Effect evaluation
Equal distribution between the intervention and control group at baseline was determined using chi-square tests for categorical variables and Student’s t-tests (normally distributed variables) or Mann-Whitney U tests (not normally distributed variables) for continuous variables. When no statistically significant unequal distributions were found at baseline, the relative risk (RR) was determined for RTW at T1 and T2, and a longitudinal multilevel analysis was performed with the group classification as an independent variable and I-RTW_CS scores at the different time point (T0, T1 and T2) as dependent variables.
In the event of significant imbalance of a prognostic factor for the primary effect measure at baseline [
13,
43], this factor was used as a covariate for the analysis of that effect measure. In that case, a logistic regression analysis was used to examine differences between the intervention and the control group with regard to RTW. For the subgroup of participants who did return to work, a longitudinal multilevel analysis was performed to examine the difference between both groups with regard to I-RTW_CS scores. We hypothesised that participants in the intervention group 1) returned to work more often and 2) with a higher I-RTW_CS score, compared to the control group.
A longitudinal multilevel analysis was performed for the secondary outcome effect measures. The group classification was set as independent variable and the QWLQ-CS score as dependent variable. For unwanted work changes (i.e. at least 1 unwanted work change), the RR was determined at T1 and T2.
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