The study, led by Iris Willems of Ghent University together with colleagues at the University of Antwerp, University Hospitals Leuven, KU Leuven and the University of South Australia, is the first to apply compositional data analysis to 24-hour movement behaviors in breast cancer survivors. This statistical framework matters because the day is a closed system of exactly 1,440 minutes. Every additional minute spent sleeping, sitting or moving must be taken from another behavior, so examining each behavior in isolation, as most earlier studies did, misses the inherent trade-offs. Compositional data analysis instead treats sleep, sedentary behavior, light physical activity and moderate-to-vigorous physical activity as interdependent parts of a whole, expressing them as isometric log-ratio coordinates that capture each behavior’s contribution relative to the others.

The participants were drawn from the EduCan trial, a randomized controlled trial conducted at the University Hospitals Leuven between November 2017 and February 2021. Women who had undergone mastectomy or breast-conserving surgery with axillary lymph node dissection wore a hip-mounted Actigraph GT3X-BT+ accelerometer for seven consecutive days at three timepoints: one week, four months and twelve months after surgery. Quality of life was assessed with the Dutch version of the McGill Quality of Life Questionnaire, which captures overall well-being, physical and existential well-being, psychological symptoms and perceived support, and also asks survivors to name the symptoms that burden them most. To interpret the survivors’ one-year profiles, the researchers compared them with 135 healthy Belgian women from a separate observational dataset collected in Ghent.

The longitudinal results tell a story of measurable but incomplete recovery. Over the twelve months following surgery, sedentary behavior declined by roughly 20 to 25 minutes per day, light physical activity rose by about 20 to 30 minutes per day, and moderate-to-vigorous activity increased by approximately 9 minutes per day. The composition at one week post-surgery differed significantly from both later timepoints, yet between four and twelve months the researchers detected no significant change, suggesting that survivors settle into a new normal of activity patterns after the initial rebound. That plateau is a striking finding, because it implies that the window for spontaneous behavioral recovery may largely close within the first few months after surgery.

When the survivors’ twelve-month profiles were set against those of healthy controls, the gaps became stark. Survivors slept about 47 minutes more per day, accumulated roughly 37 minutes less light activity and about 27 minutes less moderate-to-vigorous activity than the healthy women. At twelve months post-surgery, survivors averaged 9.3 hours of sleep per night, slightly above the 7 to 9 hours recommended for adults, along with 10.3 hours of daily sedentary time, exceeding the 8-hour ceiling suggested by the Canadian 24-hour movement guidelines. Their moderate-to-vigorous activity, at about 41 minutes per day, did surpass the widely cited threshold of 150 minutes per week, but the researchers caution that direct comparisons of accelerometer-derived means to guideline thresholds are sensitive to the choice of cut-points and processing protocols, making within-group changes and group contrasts the more reliable insights.

The prolonged sleep duration is particularly intriguing. The study measured only sleep duration, not quality, latency or nighttime waking, and the authors suggest that longer sleep may represent compensatory rest in response to fragmented or poor-quality sleep, a problem reported by more than 60 percent of breast cancer survivors. Prior research has linked both short and long sleep durations, in combination with insufficient physical activity, to elevated all-cause mortality risk among cancer survivors, which lends the observed sleep excess a potentially clinical significance beyond mere description.

The quality-of-life findings add nuance to the picture. At four months post-surgery, the overall 24-hour movement composition was significantly associated with overall quality of life, physical well-being and existential well-being, with a borderline association for perceived support. Within that composition, more time spent in light physical activity, relative to the other behaviors, was linked to better overall quality of life, while longer sleep duration, relative to the other behaviors, was associated with worse overall quality of life and less perceived support. Notably, no significant associations emerged at one week or twelve months. The authors interpret the four-month signal as reflecting a transitional phase, when acute treatment effects are fading and lifestyle behaviors are being re-established, making daily time use especially consequential for how survivors feel.

Perhaps the most sobering result concerns symptoms. At every timepoint, the symptoms survivors most frequently reported as impairing their quality of life were fatigue, insomnia and pain, with fatigue topping the list at four months, affecting 38.6 percent of participants, followed by pain in regions other than the breast or arm at 22.8 percent and insomnia at 15.8 percent. Symptom severity scores for these complaints ranged from 4.5 to 6.5 on a 10-point scale. This persistent symptom burden, the researchers note, may drain the energy needed for physical activity and, together with limited awareness of its benefits, create barriers to sustained engagement, even as accumulating evidence shows that meeting activity guidelines is associated with less fatigue, pain and anxiety.

The study is not without limitations, which the authors address candidly. There were no pre-surgery accelerometer data, so true recovery trajectories could not be reconstructed, and the healthy control group was roughly ten years younger than the survivor cohort. Control data were collected after the COVID-19 pandemic while the final survivor assessment occurred during it, and half of the survivors had received chemotherapy, which likely influenced their activity levels. Sleep in the survivor group was estimated from diaries because the accelerometer was worn only during waking hours, a protocol that may introduce measurement uncertainty compared with the 24-hour wear protocol used in controls. Dropout analysis found no significant differences between women who remained in the study and those who left, and all models were adjusted for age, pre-surgery body mass index and education level.

Even with those caveats, the implications are compelling. The first year after breast cancer surgery appears to be a period of genuine behavioral plasticity, followed by a plateau that may lock in suboptimal patterns of sleep, sitting and movement. The findings argue for interventions that treat the 24-hour day as an integrated whole, promoting light activity as an accessible, low-barrier target while monitoring sleep duration and quality rather than assuming more sleep is always better. They also underscore that fatigue, insomnia and pain deserve attention in their own right, since they shadow quality of life at every stage of recovery regardless of how survivors spend their days. For the growing population of breast cancer survivors, the message is that moving beyond cancer means more than being declared disease-free; it means rebuilding the delicate architecture of the daily rhythm that health depends on.

Subject of Research: Longitudinal changes in 24-hour movement behaviors and quality of life in breast cancer survivors during the first year after surgery

Article Title: Moving beyond cancer: longitudinal changes in 24-hour movement behaviors and their association with quality of life in breast cancer survivors

Article References: Willems, I., De Craemer, M., Dams, L., Van der Gucht, E., Miatke, A., Meeus, M., Devoogdt, N., & De Groef, A. (2026). Moving beyond cancer: longitudinal changes in 24-hour movement behaviors and their association with quality of life in breast cancer survivors. Journal of Activity, Sedentary and Sleep Behaviors, 5(1), Article 6. https://doi.org/10.1186/s44167-026-00098-y

Image Credits: AI Generated

DOI: 10.1186/s44167-026-00098-y

Keywords: breast cancer survivors, 24-hour movement behaviors, physical activity, sedentary behavior, sleep, quality of life, compositional data analysis, accelerometry, cancer survivorship, fatigue, insomnia, rehabilitation