Systematic vitamin D supplementation is associated with improved outcomes and reduced thyroid adverse events in patients with cancer treated with immune checkpoint inhibitors: results from the prospective PROVIDENCE study.

BACKGROUND: Hypovitaminosis D can have a negative prognostic impact in patients with cancer. Vitamin D has a demonstrated role in T-cell-mediated immune activation. We hypothesized that systematic vitamin D repletion could impact clinical outcomes in patients with cancer receiving immune-checkpoint inhibitors (ICIs). METHODS: We planned a prospective observational study (PROVIDENCE) to assess serum vitamin D levels in patients with advanced cancer receiving ICIs (cohort 1 at treatment initiation, cohort 2 during treatment) and the impact of systematic repletion on survival and toxicity outcomes. In an exploratory analysis, we compared the clinical outcomes of cohort 1 with a control cohort of patients followed at the participating centers who did not receive systematic vitamin D repletion. RESULTS: Overall, 164 patients were prospectively recruited in the PROVIDENCE study. In cohort 1, consisting of 101 patients with 94.1% hypovitaminosis (≤ 30 ng/ml) at baseline, adequate repletion with cholecalciferol was obtained in 70.1% at the three months re-assessment. Cohort 2 consisted of 63 patients assessed for vitamin D at a median time of 3.7 months since immunotherapy initiation, with no patients having adequate levels (> 30 ng/ml). Even in cohort 2, systematic supplementation led to adequate levels in 77.8% of patients at the three months re-assessment. Compared to a retrospective control group of 238 patients without systematic vitamin D repletion, PROVIDENCE cohort 1 showed longer overall survival (OS, p = 0.013), time to treatment failure (TTF, p = 0.017), and higher disease control rate (DCR, p = 0.016). The Inverse Probability of Treatment Weighing (IPTW) fitted multivariable Cox regression confirmed the significantly decreased risk of death (HR 0.55, 95%CI: 0.34-0.90) and treatment discontinuation (HR 0.61, 95%CI: 0.40-0.91) for patients from PROVIDENCE cohort 1 in comparison to the control cohort. In the context of longer treatment exposure, the cumulative incidence of any grade immune-related adverse events (irAEs) was higher in the PROVIDENCE cohort 1 compared to the control cohort. Nevertheless, patients from cohort 1 experienced a significantly decreased risk of all grade thyroid irAEs than the control cohort (OR 0.16, 95%CI: 0.03-0.85). CONCLUSION: The PROVIDENCE study suggests the potential positive impact of early systematic vitamin D supplementation on outcomes of patients with advanced cancer receiving ICIs and support adequate repletion as a possible prophylaxis for thyroid irAEs.

Bone recurrence in early breast cancer patients: The paradox of aromatase inhibitors induced bone resorption.

BACKGROUND: Despite the increase in chances of cure for early breast cancer (EBC) patients, approximately 20-45% of them will experience a disease recurrence, particularly bone metastases in 60-80% of cases, which occur more frequently in luminal subtypes. Endocrine therapy (ET) has always been the milestone of adjuvant treatment for hormone receptor-positive EBC patients, leading to indubitable reduction of disease recurrence risk. However, adjuvant aromatase inhibitors (AIs) therapy may promote a progressive decrease in bone mineral density (BMD), which can lead to osteoporosis. The increased bone resorption associated with osteoporosis may provide fertile soil for cancer growth and accelerate the development of bone metastases. PATIENTS AND METHODS: In this single-institution cohort study, we performed a retrospective analysis of "luminal-like" EBC patients who experienced bone recurrence after a subsequent disease free interval. The aim of the study was to evaluate the median time to skeletal recurrence (TSkR). RESULTS: 143 patients experienced bone recurrence. Median TSkR was 54 months (95%CI: 45-65). Among patients who received adjuvant AIs median TSkR was 35 months (95%CI: 25-54), while among patients who did not was 61 months (95%CI: 50-80) (HR = 1.45 [95%CI: 0.97-2.17], p = 0.0644). After adjusting for TNM stage (AJCC 8th edition), adjuvant AIs treatment was significantly related to a shorter TSkR (HR = 1.60 [95%CI: 1.06-2.42], p = 0.0244). Adjuvant Tamoxifen, adjuvant AIs/Tamoxifen and no-treatment did not revealed to be associated to TSkR. CONCLUSIONS: In this cohort of EBC patients with bone recurrence, AIs treatment seems to be related to a shorter TSkR. AIs-induced bone resorption might represent the underlying mechanism.