Dynamics of Long-Term Patient-Reported Quality of Life and Health Behaviors After Adjuvant Breast Cancer Chemotherapy

Abstract

Purpose: We aimed to characterize long-term quality of life (QOL) trajectories among patients with breast cancer treated with adjuvant chemotherapy and to identify related patterns of health behaviors.

Methods: Female stage I-III breast cancer patients receiving chemotherapy in CANTO (CANcer TOxicity; ClinicalTrials.gov identifier: NCT01993498) were included. Trajectories of QOL (European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 Summary Score) and associations with trajectory group membership were identified by iterative estimations of group-based trajectory models and multivariable multinomial logistic regression, respectively.

Results: Four trajectory groups were identified (N = 4,131): excellent (51.7%), very good (31.7%), deteriorating (10.0%), and poor (6.6%) QOL. The deteriorating trajectory group reported fairly good baseline QOL (mean [95% CI], 78.3/100 [76.2 to 80.5]), which significantly worsened at year-1 (58.1/100 [56.4 to 59.9]) and never recovered to pretreatment values through year-4 (61.1/100 [59.0 to 63.3]) postdiagnosis. Healthy behaviors were associated with better performing trajectory groups. Obesity (adjusted odds ratio [aOR] v lean, 1.51 [95% CI, 1.28 to 1.79]; P < .0001) and current smoking (aOR v never, 1.52 [95% CI, 1.27 to 1.82]; P < .0001) at diagnosis were associated with membership to the deteriorating group, which was also characterized by a higher prevalence of patients with excess body weight and insufficient physical activity through year-4 and by frequent exposure to tobacco smoking during chemotherapy. Additional factors associated with membership to the deteriorating group included younger age (aOR, 1-year decrement 1.01 [95% CI, 1.01 to 1.02]; P = .043), comorbidities (aOR v no, 1.22 [95% CI, 1.06 to 1.40]; P = .005), lower income (aOR v wealthier households, 1.21 [95% CI, 1.07 to 1.37]; P = .002), and endocrine therapy (aOR v no, 1.14 [95% CI, 1.01 to 1.30]; P = .047).

Conclusion: This latent-class analysis identified some patients with upfront poor QOL and a high-risk cluster with severe, persistent postchemotherapy QOL deterioration. Screening relevant patient-level characteristics may inform tailored interventions to mitigate the detrimental impact of chemotherapy and preserve QOL, including early addressal of behavioral concerns and provision of healthy lifestyle support programs.

FIG 1.

Trajectory groups according to best-fitting model (N = 4131). Solid lines represent the predicted trajectories and dashed lines represent the respective 95% CIs. The table below the figure displays the predicted C30 Summary Score values and respective 95% CIs by trajectory group. C30 Summary Scores were available for 3,816 patients at diagnosis, and then among 3,477 at year-1 follow-up; 3,102 at year-2 follow-up; and 2,241 patients at year-4 follow-up. Higher scores reflect better QOL. EORTC QLQ-C30, European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30; QOL, quality of life.

FIG 2.

(A) Mean QOL scores by trajectory group and by time point: EORTC QLQ-C30 functions; (B) mean QOL scores by trajectory group and by time point: EORTC QLQ-C30 symptoms. Thresholds for clinical importance are defined by horizontal, dotted gray lines. Higher scores indicate greater functionality and symptomatology. Scores below and above the threshold indicate clinically important functional impairment and symptomatology, respectively (Giesinger JM, et al: J Clin Epidemiol 2020). Respective 95% CIs for the means are available in the Data Supplement. EORTC QLQ-C30, European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30; QOL, quality of life.