Investigating Paclitaxel Toxicity in Breast Cancer: the Roles of Physical Activity and Body Composition.

Inclusion Criteria * Female patients with a diagnosis of breast cancer: Specifically targeting those diagnosed with stage II or III breast cancer, to understand the effects of paclitaxel within a somewhat uniform disease severity group. * Planned for 12 cycles of Paclitaxel (PTX) in a (neo-)adjuvant setting: The study focuses on patients scheduled to undergo a standard 12-week, once-a-week paclitaxel chemotherapy regimen as part of their treatment plan. * Age 18 or older in (pre-)menopausal status: Adult patients of any menopausal status are eligible, ensuring a wide demographic representation. * Prior taxane use is allowed if treatment in the adjuvant setting finished over a year ago: This criterion allows for the inclusion of patients who may have previously undergone taxane-based treatments, provided there has been a sufficient washout period to minimize the influence of prior treatments on the study outcomes. Exclusion Criteria * Cognitive impairment (unable to understand test instructions): Ensuring participants can comprehend and follow study procedures and requirements is crucial for data integrity and participant safety. * Participation in clinical trials of experimental drugs: To avoid confounding effects from other investigational treatments and focus on the impact of standard-of-care paclitaxel therapy. * Documented intolerance or allergy to PTX (non-documented intolerance or allergy will lead to drop-out): Participants must be able to tolerate paclitaxel, as adverse reactions could compromise their safety and affect study results. Interacting drugs in home medication: Patients using medications known to interact with paclitaxel could experience altered drug metabolism or increased toxicity, potentially skewing study outcomes. * Male sex: The study is focused on breast cancer in female patients, as the disease's presentation, treatment, and outcomes can vary significantly between genders. * Age under 18 years: Ensuring all participants are legal adults helps adhere to ethical standards and regulatory requirements concerning consent and participation in clinical research.