Prior Treatment Time Affects Survival Outcomes in Metastatic Breast Cancer.

PURPOSE: Sequential drug treatments in metastatic breast cancer (MBC) are disparate. Clinical trial data includes limited reporting of treatment context, primarily including the number of prior therapies. This study evaluates the relationship between prior treatment time, prior lines of treatment, and survival using a novel visualization technique coupled with statistical analyses. PATIENTS AND METHODS: This retrospective cohort study used a nationwide, de-identified electronic health record-derived database to identify women with hormone receptor-positive, human epidermal growth factor receptor 2-negative MBC diagnosed in 2014 who subsequently received paclitaxel. Images were created, with individual patients represented on the y-axis and time, on the x-axis. Specific treatments were represented by colored bars, with Kaplan-Meier curves overlaying the image. Separate images assessed progression-free survival and overall survival (OS). Hazard ratios (HRs) and 95% CIs from Cox proportional hazards models evaluated the association between prior treatment time and OS. RESULTS: Of 234 patients, median survival from first paclitaxel administration was 20 months (interquartile range, 8-53 months). An inverse relationship was observed between OS after paclitaxel and timing of administration. In adjusted models, each year on treatment prior to paclitaxel was associated with a 16% increased hazard of death after paclitaxel (HR, 1.16; 95% CI, 1.05 to 1.29). CONCLUSION: OS after a specific treatment is dependent on when a drug is given in the disease context, highlighting the potential for an overall OS benefit to be observed on the basis of treatment timing. Prior time on treatment should be considered as a stratifying factor in randomized trials and a confounding factor when examining survival in observational data.

Visualization of Sequential Treatments in Metastatic Breast Cancer.

PURPOSE: Treatment sequencing of metastatic breast cancer (MBC) is heterogeneous. The primary objective of this study was to develop a visualization technique to understand population-level treatment sequencing for MBC. Secondary outcomes were to describe the heterogeneity of MBC treatment sequencing, as measured by the proportion of patients with a rare sequence, and to generate hypotheses about the impact of sequencing on overall survival. METHODS: This retrospective review evaluated treatment sequencing for patients with MBC in the SEER-Medicare database. Patients with either de novo MBC or International Classification of Diseases, Ninth Revision, diagnosis codes for secondary metastasis (197.XX-198.XX) on two separate dates, excluding breast (198.81, 198.82, 198.2) and lymph nodes (196.XX), were included. Complete Medicare Parts A, B, and D coverage was required. A treatment sequence that fewer than 11 patients received was considered rare. A graphic was created with each nonrare treatment-sequence grouping on the y-axis and time on the x-axis. Bars representing time on hormonal therapy, chemotherapy, human epidermal growth factor receptor 2-targeted therapy, and other targeted therapies were color coded. Kaplan-Meier-like curves were overlaid on treatment maps, using estimated median survival for each sequence. RESULTS: Of 6,639 patients with MBC, 56% received a treatment sequence that fewer than 11 other patients received, with 2,985 other unique, rare sequences were identified. Sequence visualization demonstrated differential survival, with longer median survival for those initially receiving hormonal therapy. The median time receiving initial treatment was similar for patients receiving first-line chemotherapy. CONCLUSION: Treatment-sequence visualization can enhance the capacity to effectively conceptualize treatment patterns and patient outcomes.