Study of Vitamin D Supplementation Tailored to Vitamin D Deficiency in Breast Cancer Patients

Inclusion Criteria:

* Breast adenocarcinoma treated by neoadjuvant or adjuvant chemotherapy within 12 months prior to study enrollment
* WHO performance status 0-1
* Age ≥18 years old
* Affiliation to a social security regime or beneficiary of equivalent social protection
* Written informed consent provided before any study specific procedures

Complementary inclusion criterion for randomization

\- Proved vitamin D deficiency as defined by serum vitamin D level lower than 30 ng/ml (75 nmol/L).

Exclusion Criteria:

* Metastatic disease
* History or presence of any other malignancy (except curatively treated nonmelanoma skin cancer or in situ cervix carcinoma) ………….

traités dans les 5 ans précédents.

* Contraindication to calcium or cholecalciferol
* Known severe hypersensitivity to vitamin D or to calcium supplementation or to one of the excipients.
* Disease and/or medical conditions accompanied by hypercalcaemia and/or hypercalciuria
* Calcium lithiasis and tissue calcification
* Hypervitaminosis D
* Presence of significant comorbidities:

  i) Uncontrolled endocrine disease ii) Known disorders of calcium phophorus laboratory testing iii) Proved osteopenia or osteoporosis requiring vitamin D and calcium supplements
* Concomitant treatment with other experimental products or another vitamin D calcium treatment
* Pregnancy, breastfeeding or of reproductive potential not using an effective contraceptive method
* Legal inability or restricted legal ability. Medical or psychological conditions not allowing proper study completion or informed consent signature