Development and initial validation of the NCCN/FACT symptom index for advanced kidney cancer

Abstract

Objectives: There is a need for a brief symptom index for advanced kidney cancer that includes perspectives of both patients and clinicians and is consistent with the Food and Drug Administration's guidance for patient-reported outcome measures. This study developed and examined the preliminary reliability and validity of the new National Comprehensive Cancer Network/Functional Assessment of Cancer Therapy (FACT)-Kidney Symptom Index 19.

Methods: Fifty patients with advanced kidney cancer provided open-ended and survey responses ranking their most important symptoms. Responses were reconciled with published clinician reports of the most important symptoms. Ten experienced oncologists rated symptoms as disease- or treatment-related. Patients completed quality-of-life and performance status measures.

Results: A 19-item index was produced from symptoms that were rated as most important by patients or clinicians. It includes three subscales: disease-related symptoms (DRS), treatment side effects (TSE), and general function and well-being (FWB). Internal consistency was good for the full instrument (α = 0.83), the DRS subscale (α = 0.76), and the FWB subscale (α = 0.78) but lower for the TSE subscale (α = 0.59). Convergent validity was demonstrated through correlations with the FACT-General. Patients with differing performance status were distinguished by the total score (F2,47 = 17.37; P < .0001), the DRS subscale (F2,47 = 14.22; P < .0001), and the FWB subscale (F2,47 = 13.40; P < .0001) but not the TSE subscale (F2,47 =1.48; P = 0.2380).

Conclusions: The National Comprehensive Cancer Network/FACT-Kidney Symptom Index 19 combines symptoms deemed most important by patients and clinicians. Preliminary evidence suggests that the total score and DRS and FWB subscales are reliable and valid as summary indexes. The TSE subscale may be least relevant given the advent of newer therapies.

Keywords: cancer; patient-reported outcomes; quality of life; symptoms.