The objective of this randomized controlled trial (RCT) is to evaluate the effectiveness of the MiLES intervention targeted at employers, on successful return to work (RTW) of employees with cancer, compared to care as usual (CAU).

Secundary objectives are:

• To evaluate the cost-effectiveness and return-on-investment of the MiLES intervention on successful RTW and quality of life, compared to CAU.
• To evaluate the effectiveness of the MiLES intervention on several outcome measures on the level of the employee with cancer (time to RTW, quality of life, quality of working life, received work-related support, and satisfaction with work-related support), and the level of the employer (self-efficacy in providing RTW support, and satisfaction with the RTW process).

Participants will be 140 employer-employee with cancer dyads. All dyads will randomly be allocated to the intervention group, of which the employer will get unlimited access to the MiLES intervention, or to the control group in which CAU will be provided. The follow-up of this study will be 12 months.

Along with the RCT, a process evaluation using the UK Medical Research Council framework will also be conducted.

The investigators will include 140 employer-employees with cancer dyads. The employees are diagnosed with cancer (<2 years earlier), aged 18-65 years, in paid employment with an employer, and currently fully or partly sick-listed (<2 years). The employer supports and guides the participating employee with cancer during the period of sick leave and RTW (e.g. as the direct supervisor or HR-manager).

Employers of dyads randomized to the intervention group will get unlimited access to the web-based MiLES intervention, aimed at enhancing the successful RTW of employees with cancer, by supporting employers. This intervention includes among others interactive video's, conversation checklists, and tips and information. Employers of dyads randomized to the control group will not get access to the MiLES intervention, thus dyads will get care as usual.

The primary outcome will be successful RTW, measured at the level of the employee. Secondary outcomes will include: current work situation (including time to RTW), quality of life and quality of working life, received work-related support, and satisfaction with work-related support. At the level of the employer, the secondary outcomes will include: self-efficacy in providing RTW support, and satisfaction with the RTW process. All outcomes will be assessed using questionnaires at baseline and at 3, 6 and 12 months of follow-up. Both the cost-effectiveness and the return on investment analysis will be conducted from the employers perspective. For the process evaluation, the UK MRC framework will be used.

Inclusion criteria employees with cancer:

• Diagnosed with cancer &lt;2 years earlier;
• Being of working age (between 18-65 years, considering the Dutch retirement age of 67 years, and the study's follow-up period of one year);
• In paid employment with an employer;
• Having either an occupational physician at the involved occupational health service or a reintegration consultant at the involved reintegration service (e.g. working for an organization that is affiliated with one of the settings of this study);
• Currently fully or partly sick-listed (&lt;2 years);
• Able to understand and read Dutch for filling out questionnaires;
• Having already informed their employer about their diagnosis of cancer, or intending to do so;
• Not yet applied or planning to apply for an invalidity benefit under the WIA.

Inclusion criteria employers:

• Supports and guides the participating employee with cancer during the period of sick leave and RTW. For example, as the direct supervisor or HR-manager;
• Able to understand and read Dutch to be able to use the MiLES intervention and for filling out questionnaires;
• Not yet familiar with the MiLES intervention.

Exclusion Criteria:

- Employees with cancer and their employers must participate as a dyad. If one party in the dyad is unable or unwilling to participate, the other party cannot participate either.

Not yet determined

Participants will not be blinded, as it was hard to devise a placebo intervention, and the standard care (no access to the MiLES intervention) was obviously different from the intervention (access to the MiLES intervention).