Phase One Development of a Patient-Reported Outcome Measure for Low Anterior Resection Syndrome

Background

The Low Anterior Resection Syndrome (LARS) score is an internationally validated instrument for identifying bowel dysfunction following anterior resection for rectal cancer. Although widely used, it has been shown to have limited sensitivity for capturing the impact of LARS on daily-life and response to treatment. We have therefore developed a novel patient-reported outcome measure (PROM): the LARS Impact and Consequences Assessment Tool (LARS-ICAT).

Methods

Initial development of LARS-ICAT followed a five-stage process following established PROM development guidance. Stage one established the conceptual foundation through previously published Delphi consensus. Stage two involved item generation, followed by evaluation of content validity through patient focus groups (n=11) in stage three. Stage four comprised iterative expert review and refinement through clinical consensus with patient involvement. Stage five involved cognitive interviews with patients conducted across five rounds (n=23).

Results

Several items identified through the Delphi consensus were reworded as they included multiple concepts. A one-month recall period was selected, with six and four response options for symptom and consequence items respectively. Additional consequence items, including impact on sleep and transport use, were incorporated. Focus groups and clinicians emphasised the importance of capturing individual symptom burden, leading to the addition of symptom bother scales. These iterative refinements culminated in LARS-ICAT v2.6.

Conclusions

LARS-ICAT is a novel PROM designed to assess symptom burden and treatment response in LARS. Future studies will assess its psychometric properties. Once validated, LARS-ICAT will provide a comprehensive, patient-centred assessment of LARS, enhancing our ability to manage this challenging condition.

Strengths and Limitations

• The LARS-ICAT was specifically designed to measure change over time and responsiveness to treatment, addressing important limitations of existing instruments, such as the LARS score.

• Input from patients and experts across multiple countries improved the content validity and cross-cultural relevance of the PROM.

• This work also led to the establishment of the LARS Collaborative, an international research group dedicated to advancing education, engagement and understanding of LARS and its management.

• The study included only English-speaking participants, which may limit the generalisability of the instrument to non-English-speaking populations until formal translation, linguistic validation and cross-cultural validation has been undertaken.