Defining clinical benefit in postmenopausal patients with breast cancer under second-line endocrine treatment: Does quality of life matter?

Purpose: In endocrine therapy trials in advanced breast cancer, patients wi th response (complete response/partial response [CR/PR]) and patients with stable disease for at least 6 months (SD6m) have shown similar survival and therefore are often defined as a population with clinical benefit (patient s with CR/PR or SD6m). We evaluated the impact of response and/or clinical benefit on quality of life (QL) in postmenopausal patients under second-lin e endocrine treatment after failure of tamoxifen. Patients and Methods: One hundred twenty-eight of 177 eligible patients of a randomized trial (Swiss Group for Clinical Cancer Research 20/90) receivi ng either formestane (250 mg intramuscularly biweekly) or megestrol acetate (160 mg orally daily) were analyzed. The baseline characteristics (with th e exception of site of metastases) were balanced among patients with CR/PR, SD6m, and progressive disease (PD). patients completed QL indicators at ba seline and at 1, 3, 5, 7, 9, and 11 months. Responders were separately comp ared with nonresponders (patients with SD6m or PD) and with patients with S D6m, and patients with clinical benefit were compared with patients with PD by analysis of covariance with adjustment for baseline scores. Results: Overall, 88% (557 of 634) of expected Qb forms were received. In t he comparison of responders versus patients with both SD6m and PD, responde rs indicated better physical well-being (P = .004) and mood (P = .02) at mo nth 3, Compared only with patients with SD6m, responders showed no signific ant difference in baseline OL and time to treatment failure (328.5 v 340 da ys). While under treatment, responders reported significantly better physic al well-being (months 3 to 11), mood (months 5 to 11), coping (months 5 to 9), and appetite (months 7 to 11) and less dizziness (month 9) than patient s with SD6m. The changes between baseline and months 5 and 7, respectively, indicated improvement in responders but heterogeneous patterns in patients with SD6m. Conclusion: Although the CR/PR and SD6m groups had similar rimes to treatme nt failure, patients with CR/PR reported better QL, suggesting more benefic ial response to second-line endocrine treatment. patients' subjective persp ective should be taken into account in this mainly palliative setting. Futu re trials should be designed sc that the CR/PR and SD6m groups are investig ated separately. (C) 1999 by American Society of Clinical Oncology.