The influence on quality of life of intermittent scheduling in first- and second-line chemotherapy of patients with HER2-negative advanced breast cancer.

Background: The Stop&Go study randomized patients with advanced breast cancer to intermittent (two times four) or continuous (eight subsequent cycles) first- and second-line chemotherapy.

Methods: QoL was measured with RAND-36 questionnaires every 12 weeks. The primary objective was to estimate differences in changes from baseline between intermittent and continuous treatment. An effect size of 0.5 SD (5 points) was considered clinically meaningful.

Results: A total of 398 patients were included with a median follow-up of 11.4 months (IQR 5.6-22.2). Mean physical QoL baseline scores were 38.0 resp. 38.2, and mental scores 45.0 resp. 42.4 for intermittent and continuous treatment. Physical QoL declined linearly in the intermittent arm causing a clinically meaningful difference of 5.40 points at 24 months (p < 0.001), while scores in the continuous arm stabilized after a small decline of ± 3.4 points at 12 months. Conversely, mental QoL was fairly stable and even improved with 1.58 (p = 0.005) and 2.48 points (p < 0.001) at 12 months for intermittent and continuous treatment, respectively. When comparing arms for both components in changes from baseline, the maximum differences were 2.46 (p = 0.101) and 1.95 points (p = 0.182) for physical and mental scores, both measured at 30 months and in favor of continuous treatment.

Conclusion: Intermittent first- and second-line chemotherapy in patients with HER2-negative advanced breast cancer showed a trend for worse impact on QoL compared to continuous chemotherapy, with neither significant nor meaningful differences in course. We recommend prescribing chemotherapy continuously until progressive disease or unacceptable toxicity. Trial registration EudraCT 2010-021519-18; BOOG 2010-02.