Time to Deterioration in Quality of Life Score as a Modality of Longitudinal Analysis in Patients with Breast Cancer

Abstract

This prospective multicenter study explored different definitions of time to deterioration (TTD) in quality of life (QoL) scores, according to different cutoffs of the minimal clinically important difference (MCID) as a modality for longitudinal QoL assessment in breast cancer patients. QoL was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 and BR-23 before surgery, after surgery, and 6 and 12 months later. The global health score, arm symptoms score (BRAS), and breast symptoms score were analyzed. For a given baseline score, QoL was considered to have deteriorated if this score decreased by ≥5 points at any time point after baseline. Analyses were repeated using an MCID of 10 points and taking the score after surgery as the reference score (to explore the occurrence of response shift). TTD was calculated using the Kaplan-Meier method and Cox regression was used to identify independent factors associated with TTD. Two hundred thirty-five patients underwent axillary lymph node dissection (ALND), 222 underwent sentinel lymph node biopsy (SLNB), and 61 underwent SLNB plus ALND. Patients who underwent SLNB had a significantly longer TTD for the BRAS dimension than those who underwent ALND. Cox multivariate analyses showed that treatment using SLNB and age >59 years were independently associated with longer TTD for the BRAS, whereas surgery elsewhere than at the Centre Georges François Leclerc was associated with a shorter TTD. Exploration of different definitions of TTD in QoL provides meaningful longitudinal QoL results for clinicians.