New for DESI study (if offered choice of either pet or surgery/AET, or chemotherapy/no chemotherapy)	Baseline (after consent for PET or surgery) (AET or after consultation for chemo/no chemo, as applicable)	6 weeks after relevant treatment choice	6 months after relevant treatment choice
Spielberger anxiety		*	*
Collaborate	*
Decision regret		*	*
Knowledge readiness to decide and preference measures	*
Brief IPQ		*	*
Brief COPE		*	*
Process evaluation (if taking part in process evaluation)
Process evaluation questionnaire		*

*indicated that these data are collected at this time point.

ADL, activities of daily living; AET, antioestrogen therapy; COPE, Coping Orientation to Problems Experienced; DESI, decision support intervention; ECOG, Eastern Cooperative Oncology Group; IADL, instrumental activities of daily living; IPQ, Illness Perception Questionnaire; MMSE, Mini-Mental State Examination; PET, primary endocrine therapy; QoL, quality of life; RECIST, Response Evaluation Criteria In Solid Tumors.