Chemotherapy interruptions in relation to symptom severity in advanced breast cancer
Interruptions in medical treatment such as dose delays, reductions, or stoppages can lead to suboptimal treatment of cancer. Knowing how and for whom symptom severity and symptom interference with activities of daily living (ADL) are associated with treatment interruptions can guide behavioral interventions for supportive care. The purpose of this analysis is to inform research and clinical practice by bringing attention to specific patient symptoms that may hinder dose completion. A secondary analysis of data collected in a randomized clinical trial (RCT) of reflexology for symptom management was performed. The trial enrolled women with advanced breast cancer undergoing treatment (N = 385). Outcome data were collected at baseline, weeks 5 and 11 using valid and reliable measures. Medical records provided data on treatment interruptions and metastasis. The association between alterations in medical treatment during the study period with symptom severity, symptom interference with ADLs, and metastatic status were tested using generalized estimating equation (GEE) models. The relationship between dose delays and dose reductions and symptom severity was differential according to metastatic status, with the higher strength of association among women with distant metastasis compared to those with loco-regional disease (p = 0.02). The interaction of symptom interference and metastatic status was also significantly related to dose delays and reductions (p = 0.04). Severity of pain was a stronger predictor of dose delays or reductions among patients with distant metastasis compared to those with loco-regional disease (p < 0.01). The analysis highlights the importance of understanding symptom outcomes that impact research, practice, and treatment decisions.