One twenty three subjects who completed adjuvant chemotherapy for early colon cancer 3–60 months earlier completed a questionnaire; 97 were randomised to complete an interview before or after the questionnaire. Preferences were elicited by the time trade-off method in 4 hypothetical scenarios. Concordance between the interview and questionnaire was assessed with the intraclass correlation coefficient (ICC).
Median age was 65 years (range 19–86), 52 % were female and 74 % had involved lymph nodes. Over 60 % of patients judged an additional 1 month beyond life expectancies of 5 years or 15 years, and an additional 1–2 % beyond 5-year survival rates of 85 % or 65 % , sufficient to make chemotherapy worthwhile. Subjects with tertiary education (p = 0.003) or aged 75 years or less (p = 0.02) judged larger benefits necessary to make chemotherapy worthwhile. Concordance between the interview and questionnaire was high (ICCs 0.71–0.82).
Most subjects judged small survival benefits sufficient to make adjuvant chemotherapy worthwhile. A self-administered questionnaire was a valid and acceptable way of eliciting preferences.