Patients' and clinicians' preferences for adjuvant chemotherapy in endometrial cancer: an ANZGOG substudy of the PORTEC-3 intergroup randomised trial

BACKGROUND: To determine the minimum survival benefits that patients, and their clinicians, judged sufficient to make adjuvant chemotherapy (ACT) worthwhile, in addition to pelvic radiotherapy, for women with high risk and advanced stage endometrial cancer. METHODS: Eighty-three participants in the PORTEC-3 trial completed a time trade-off questionnaire before and after adjuvant therapy; 44 of their clinicians completed it once only. The questionnaire used four hypothetical scenarios including baseline survival times without ACT of 5 and 8 years, and baseline survival rates at 5 years without ACT of 50 and 65%. RESULTS: Over 50% of patients judged an extra 1 year of survival time or an extra 5% in survival rate sufficient to make ACT worthwhile. Over 50% of clinicians judged an extra 1 year of survival time, or an extra 10% in survival rate, sufficient to make ACT worthwhile. Compared with patients, clinicians required similar survival time benefits (medians both 1 year, P=0.4), but larger survival rate benefits (medians 8.5% vs 5%, P=0.03), and clinicians' preferences varied less (IQR 0.5–1.5 years vs 0.4–2 years, P=0.0007; 5–10% vs 1–13%, P=0.004). Patients' preferences changed over time for the survival rate scenarios depending on whether they had ACT or not (change in median benefit - 3 months vs 2.5 months respectively, P=0.028). There were no strong predictors of patients' or clinicians' preferences. CONCLUSIONS: Patients and clinicians judged moderate survival benefits sufficient to make ACT worthwhile after pelvic radiotherapy for endometrial cancer. These benefits are larger than those judged sufficient by patients with breast or colon cancers, but similar to those judged sufficient by patients with lung or ovarian cancers.