Quantifying preferences for watch-and-wait compared with surgery after a clinical complete response in rectal cancer: a discrete choice experiment

Purpose: To quantify the preferences of individuals with and without experience of cancer when making a treatment decision between a watch-and-wait programme and surgery after a clinical complete response in rectal cancer. Methods: An online discrete choice experiment quantified the preferences of a purposive sample of UK-based adults with and without experience of cancer (recruited using an online-panel provider; Pureprofile). Respondents chose their preferred labelled alternative from watch-and-wait and surgery. A literature review with input from patients and clinicians identified six attributes with four levels (delayed surgery, cancer metastases, faecal urgency, time until stoma, number of follow-up visits, health status) and one attribute with eight levels (survival, four levels for high uncertainty and four levels for low uncertainty). The experimental design consisted of four blocks of 10 choice sets generated to minimise the D-error. Respondents were asked background questions about themselves, their experience of cancer, their views on cancer treatment and their attitude towards healthcare decision-making. Choice data were analysed using a random parameters logit (RPL) model and uptake probabilities were calculated. Results: Choice data were collected from 398 (51% female; mean age 59 years) individuals with experience of cancer and 949 (51% female; mean age 59 years) individuals without experience of cancer. Estimated coefficients from the RPL model indicated that six out of seven attributes were statistically significant predictors of choice in both samples. Chance of needing a delayed surgery did not influence the choice between alternatives in either sample. In general, individuals preferred longer time until stoma, lower chance of metastases and faecal urgency, lower number of follow-up visits, and increased survival and health. The absence of statistical significance for the alternative-specific constant term indicated that respondents in either sample did not have an intrinsic desire for watch-and-wait or surgery. Evidence of preference heterogeneity was present for all attributes in the cancer-experience sample and six attributes within the cancer-naïve sample. Calculated uptake indicated that there was a 50% and 53% probability of a respondent choosing watch-and-wait in the cancer-experience and cancer-naïve sample, respectively. Conclusions: This study quantified preferences for watch-and-wait compared with surgery and indicated a need for explaining the benefits and harms of each option to enable patients to make an informed decision, indicating a potential role for a patient decision aid in this context.