Response Shift-Adjusted Treatment Effect on Health-Related Quality of Life in a Randomized Controlled Trial of Taxane Versus S-1 for Metastatic Breast Cancer: Structural Equation Modeling.

OBJECTIVE: We investigated the quantification of the response shift-adjusted treatment effect on quality-of-life (QOL) data in a randomized controlled trial of taxane versus S-1 for patients with metastatic breast cancer (SELECT-BC). METHODS: This study was a secondary data analysis of a previously published trial. The response shift-adjusted treatment effect on health-related QOL (HRQOL) data measured by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) was estimated using structural equation modeling techniques in addition to quantifying the "true" treatment effect. Measurement invariances in the values of the common factor loadings, intercepts, and residual variances between before treatment and at the 3-, 6-, and 12-month visits were considered the response shift effects. RESULTS: In the taxane group, we observed positive recalibration effects for role functioning and positive reprioritization and negative recalibration effects for emotional functioning. The observed change of -4.56 for role functioning comprised +2.26 response shifts and -6.82 "true" change. The observed change of +9.41 for emotional functioning comprised +12.43 response shifts and -1.17 "true" change. In the S-1 group, we observed positive reprioritization and negative recalibration effects for emotional functioning and positive reprioritization effects for social functioning. The observed change of +10.54 for emotional functioning comprised +10.07 response shifts and +0.47 "true" change. The observed change of +2.43 for social functioning comprised +3.50 response shifts and -1.07 "true" change. CONCLUSION: Detailed analysis of the response shift effects will improve the evaluation reliability of observed HRQOL data during clinical trials.

Feasibility and validity of the Patient Neurotoxicity Questionnaire during taxane chemotherapy in a phase III randomized trial in patients with breast cancer: N-SAS BC 02.

GOALS: The aim of the study was to determine the feasibility and validity of a newly developed patient-based instrument--the Patient Neurotoxicity Questionnaire (PNQ)--for grading chemotherapy-induced peripheral neuropathy (CIPN). PATIENTS AND METHODS: We prospectively collected data from 300 female patients who were treated with taxane chemotherapy for primary breast cancer as part of a national multicenter phase III randomized trial (N-SAS BC 02). We evaluated patient compliance with the PNQ and several validation parameters, including concordance between CIPN grades noted by physicians (National Cancer Institute Common Toxicity Criteria) and patients (PNQ), and the concurrent validity and responsiveness of the PNQ versus the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) utilizing data at pre-treatment and before three, five, and seven treatment cycles. MAIN RESULTS: The questionnaire completion rate was >90% at all assessments. Evaluation by physicians always resulted in lower neuropathy assessment scores compared with those reported directly by patients (weighted kappa coefficients, 0.02-0.06). Both PNQ sensory and motor scores were significantly correlated with the FACT/GOG-Ntx (r = 0.66 and 0.51, respectively). In the repeated measures analysis of variance model, PNQ grades increased considerably as treatment continued, indicating progressively worsening CIPN over time. CONCLUSIONS: The PNQ has an applicable degree of feasibility and validity, useful for the diagnosis of CIPN as well as for clinical treatment decision-making, where the development of CIPN is a potential treatment-limiting consideration. Physicians underreport and underestimate the severity of CIPN symptoms compared with patients, thereby supporting the importance of assessing patient-reported outcomes using the PNQ.