Process evaluation of a multicentre randomised clinical trial of substituting surgical excisions of low-risk basal cell carcinomas from secondary to primary care

Objectives
In 2016, the SKINCATCH Trial, a clustered multi-centre randomised trial, was initiated to assess whether low-risk basal cell carcinomas (BCCs) can be treated by general practitioners (GPs) without loss of quality of care. The trial intervention consisted of a tailored 2-day educational course on skin cancer management. The aim of this process evaluation was to investigate GPs' exposure to the intervention, implementation of the intervention and experiences with the intervention and trial. 

Research design and methods
Data on exposure to the intervention, implementation and experiences were obtained at several points during the trial. Complementary quantitative components (ie, surveys, database analysis, medical record analysis) and qualitative components (ie, interviews and focus groups) were used. Quantitative data were analysed using descriptive statistics; qualitative data were summarised (barrier interviews) or audiorecorded, transcribed verbatim and thematically analysed using Atlas.Ti (focus groups). 

Results
Following a 100% intervention exposure, results concerning the implementation of the trial showed that aside from the low inclusion rate of patients with low-risk BCCs (n=54), even less excisions of low-risk BCCs were performed (n=40). Although the intervention was experienced as highly positive, several barriers were mentioned regarding the trial including administrative challenges, lack of time and high workload of GPs, low volume of BCC patients and patients declining to participate or requesting a referral to a dermatologist. 

Conclusions
Although GPs' participation in the highly valued training was optimal, several barriers may have contributed to the low inclusion and excision rate of low-risk BCCs. While some of the issues were trial-related, other barriers such as low patient-volume and patients requesting referrals are applicable outside the trial setting as well. This may question the feasibility of substitution of surgical excisions of low-risks BCCs from secondary to primary care in the current Dutch setting. Trial registration number Trial NL5631 (NTR5746).