A Plea for Monitoring Serum Selenium Levels in Breast Cancer Patients: Selenium Deficiency Is Rare during the First Year of Therapy, and Selenium Supplementation Is Associated with Elevated Risk of Overdosing.

(1) Background: The role of selenium in cancer biology remains poorly understood. Our aim was to study the course of selenium serum levels and the use of selenium supplements during breast cancer therapy. (2) Methods: Serum selenium levels, clinical-pathological data, selenium supplementation, and lifestyle factors were monitored quarterly over one year. (3) Results: A total of 110 non-metastatic breast cancer patients were enrolled in the prospective observational "BEGYN-1" study. At baseline, 2.9% of patients were selenium-deficient (<50 ng/mL), 1.9% were overdosed (>120 ng/mL), and 6.4% received substitution. The median selenium level was 81.5 ng/mL and ranged between 78.7 and 84.5 ng/mL within the year. A total of 25.3% of the patients received supplementation, resulting in significantly higher selenium levels (p < 0.05). A total of 8.7-28.6% of the patients using supplements were overdosed. Selenium levels strongly correlated with mushroom consumption (p = 0.003), but no association was found with therapy or clinical characteristics. (4) Conclusions: Although selenium deficiency is rare, serum selenium levels should be assessed in breast cancer patients. Mushrooms and nuts should be preferred over supplements to correct selenium deficiency. Ruling out selenium deficiency helps prevent the risk of selenosis and avoid unnecessary, costly supplementation in patients who are often financially burdened due to their disease.

Course of Vitamin D Levels in Newly Diagnosed Non-Metastatic Breast Cancer Patients over One Year with Quarterly Controls and Substitution.

(1) Background: Vitamin D levels in patients remain inadequately understood, with research yielding inconsistent findings. Breast cancer patients, particularly due to oncological therapies, face an increased risk of osteopenia, which can be exacerbated by a vitamin D deficiency. (2) Methods: The prospective observational "BEGYN-1" study assessed serum 25(OH)D levels at baseline and quarterly thereafter. Clinical, pathological, nutritional, vitamin supplementation, and lifestyle data were recorded. (3) Results: Before treatment, 68.5% of patients were vitamin D deficient (<30 ng/mL), with 4.6% experiencing severe deficiency (<10 ng/mL). The median baseline 25(OH)D levels were 24 ng/mL (range: 4.8 to 64.7 ng/mL). Throughout the study, the median vitamin D levels increased to 48 ng/mL (range: 22.0 to 76.7 ng/mL). Before diagnosis, 16.7% received vitamin D substitution, and 97.8% received vitamin D substitution throughout the year with a median weekly dose of 20,000 IU. It took at least three quarterly assessments for 95% of patients to reach the normal range. A multiple GEE analysis identified associations between 25(OH)D levels and supplementation, season, age, VLDL, magnesium levels, and endocrine therapy. (4) Conclusions: Physicians should monitor 25(OH)D levels before, during, and after oncological therapy to prevent vitamin D deficiency and to adjust substitution individually. While variables such as seasons, age, VLDL, magnesium, diet, and oncological interventions affect 25(OH)D levels, supplementation has the greatest impact.

Improved awareness of physical activities is associated with a gain of fitness and a stable body weight in breast cancer patients during the first year of antineoplastic therapy: the BEGYN-1 study.

Background: Breast cancer is the most frequent cancer in women. Reduced physical activity and overweight are associated with poor prognosis. Breast cancer patients have a high risk to gain weight, lose muscle mass and reduce physical activity during therapy. Concepts are urgently needed to motivate patients to engage in physical activity. Methods: 110 non-metastatic breast cancer patients were included in the prospective observational BEGYN-1 study. Physiological parameters and body composition were measured before the start of therapy and then quarterly for one year. Patients used a fitness tracker and documented their physical activity in a diary throughout the study. Results: Although the patients were not offered any guided exercise, and despite the restrictions during the COVID-19 pandemic, they increased their physical activity (metabolic equivalent of task (MET) -minutes): p<0.001), physical fitness (decreasing resting heart rate: p=0.001) and did not gain weight (median - 0.4kg) over the course of the study. Conclusion: Improved awareness of physical activity is associated with an increase in physical activity, fitness, and a stable weight during the first year of therapy in breast cancer patients. Counselling at diagnosis should motivate patients to engage in physical activity, wear a fitness tracker and document activities.

Prevalence and Relevance of Vitamin D Deficiency in Newly Diagnosed Breast Cancer Patients: A Pilot Study.

(1) Background: Vitamin D plays an important role in many types of cancer. It was the aim of this study to analyze serum 25-hydroxyvitamin D (25(OH)D) levels in newly diagnosed breast cancer patients, and the association with prognostic and lifestyle factors. (2) Methods: 110 non-metastatic breast cancer patients were included in the prospective observational "BEGYN" study at Saarland University Medical Center between September 2019 and January 2021. At the initiation visit, serum 25(OH)D levels were measured. Clinicopathological data on prognosis, nutrition, and lifestyle were extracted from data files and obtained using a questionnaire. (3) Results: Median serum 25(OH)D in breast cancer patients was 24 ng/mL (range 5-65 ng/mL), with 64.8% of patients being vitamin D deficient. 25(OH)D was higher among patients that reported the use of vitamin D supplements (43 ng/mL versus 22 ng/mL; p < 0.001), and in summer compared to other seasons (p = 0.03). Patients with moderate vitamin D deficiency were less likely to have triple negative breast cancer (p = 0.047). (4) Conclusions: Routinely measured vitamin D deficiency is common in breast cancer patients and needs to be detected and treated. However, our results do not support the hypothesis that vitamin D deficiency may be a main prognostic factor for breast cancer.

Longitudinal Assessment of Physical Activity, Fitness, Body Composition, Immunological Biomarkers, and Psychological Parameters During the First Year After Diagnosis in Women With Non-Metastatic Breast Cancer: The BEGYN Study Protocol.

BACKGROUND: Moderate physical activity is associated with an improved prognosis and psychosocial outcome in breast cancer patients. Although exercise and physical activity are associated with multiple physiological and psychological effects, many of the underlying mechanisms remain obscure. The BEGYN study (Influence of physical activity in breast cancer patients on physiological and psychological parameters and on biomarkers) aims at identifying potential associations between the extent of physical activity, fitness, body composition, immunological biomarkers, psycho-emotional parameters, and the course of treatment during the first year after diagnosis of breast cancer. METHODS: The prospective observational BEGYN study will include 110 non-metastatic breast cancer patients. The patients will be assessed during a base line visit prior to the initiation of the antineoplastic therapy and after 3, 6, 9 and 12 months. The physical activity will be measured using a fitness tracker and a self-assessment diary during the entire study. Each visit will include the assessment of (i) cardiorespiratory fitness measured by spiroergometry, (ii) body composition, (iii) psycho-emotional parameters (quality of life, mental health, fatigue, depression, distress, anxiety, well-being), and (iv) extensive blood tests including routine laboratory, vitamin D, selenium and immunologically relevant biomarkers (e.g., leukocyte subpopulations and cytokine profiles). DISCUSSION: Whereas most studies investigating the influence of physical activity in breast cancer patients focus on specific activities for three months or less, the BEGYN study will quantify the daily physical activity and cardiorespiratory fitness of breast cancer patients based on objective measurements in the context of the oncological therapy for 12 months after diagnosis. The study will reveal potential associations between exercise, immune status and physical as well as psycho-emotional outcome and the clinical course of the disease. Moreover, complementary therapies such as Vit D and Selenium supplementation and parameters investigating the motivation of the patients are part of the study. Due to this holistic approach, the BEGYN study will guide towards confirmatory studies on the role of physical activity in breast cancer patients to develop individualized counselling regarding the recommended type and extent of exercise. TRIAL REGISTRATION: This study has been registered at the German Clinical Trials Register DRKS00024829.