Responsiveness, the ability of a measure to accurately detect change when it has occurred, was evaluated in six questionnaires used in the "Breast Expressive-Supportive Therapy" study in metastatic breast cancer: Profile of Mood States (POMS), Impact of Event Scale, Psychosocial Adjustment to Illness Scale (PAIS), EORTC QLQ-C30, Mental Adjustment to Cancer and a pain visual analog scale. We assessed responsiveness to change in three scenarios: the effect of supportive-expressive group therapy (SEGT), improvement in mood by more than a small effect size in POMS Total Mood Disturbance score and progression of disease. At the group level, POMS was the most responsive to SEGT but for progression of disease, EORTC QLQ-C30 and PAIS were the most responsive. PAIS psychological and EORTC QLQ-C30 emotional subscales showed small to moderate effect sizes for improvement in mood. At the individual level, POMS was associated with the largest proportion of patients who improved with SEGT.