Disease and treatment characteristics do not predict symptom occurrence profiles in oncology outpatients receiving chemotherapy

Abstract

Background: A large amount of interindividual variability exists in the occurrence of symptoms in patients receiving chemotherapy (CTX). The purposes of the current study, which was performed in a sample of 582 oncology outpatients who were receiving CTX, were to identify subgroups of patients based on their distinct experiences with 25 commonly occurring symptoms and to identify demographic and clinical characteristics associated with subgroup membership. In addition, differences in quality of life outcomes were evaluated.

Methods: Oncology outpatients with breast, gastrointestinal, gynecological, or lung cancer completed the Memorial Symptom Assessment Scale before their next cycle of CTX. Latent class analysis was used to identify subgroups of patients with distinct symptom experiences.

Results: Three distinct subgroups of patients were identified (ie, 36.1% in Low class; 50.0% in Moderate class, and 13.9% in All High class). Patients in the All High class were significantly younger and more likely to be female and nonwhite, and had lower levels of social support, lower socioeconomic status, poorer functional status, and a higher level of comorbidity.

Conclusions: Findings from the current study support the clinical observation that some oncology patients experience a differentially higher symptom burden during CTX. These high-risk patients experience significant decrements in quality of life.

Keywords: chemotherapy; latent class analysis; precision medicine; quality of life; symptom clusters; symptom profiles.

Figure 1

Probability of symptom occurrence for the total sample (i.e., sample proportion) and each of the latent classes for the 25 symptoms on the Memorial Symptom Assessment Scale that occurred in ≥40% of the total sample (n=582).

Figure 2

Figure 2A – Differences among the latent classes in the subscale and summary scores for the Medical Outcomes Study-Short Form 12 (SF-12). All values are plotted as means ± standard deviations. Significant differences: For PF: Low>Moderate (p<.0001) >All High (p=.002). For RP, BP, SF, RE, MH, and MCS: Low>Moderate>All High (both p<.0001). For GH: Low>Moderate and All High (p<.0001). For VT: Low>Moderate (p<.0001) >All High (p=.037). For PCS: Low>Moderate (p<.0001) > All High (p=.006). Abbreviations: PF=physical functioning, RP=role physical, BP=bodily pain, GH=general health, VT=vitality, SF=social functioning, RE=role emotional, MH=mental health, PCS=physical component summary, MCS=mental component summary. Figure 2B - Differences among the latent classes in the subscale and total quality of life (QOL) scores for the Quality of Life Scale-Patient Version (QOL-PV). All values are plotted as means ± standard deviations. Significant differences: Physical, Psychological, and Social Functioning subscales and total QOL scores: Low>Moderate>All High (both p<.0001).