Evaluating the role of vitamin D supplementation in patients with breast cancer receiving doxorubicin chemotherapy.

The study investigated the effects of vitamin D (Vit D) supplementation in patients with early breast cancer receiving doxorubicin (DOX; Adriamycin)-based chemotherapy. The results showed that patients taking DOX plus Vit D had improved heart-related blood markers.

The main treatment for early breast cancer is surgery to remove the tumor. Many patients also receive additional therapy after surgery to lower the risk of cancer coming back. This is called adjuvant therapy. It can be given as chemotherapy, radiation therapy, hormone therapy, or targeted (biological) therapy.

Adjuvant DOX-based chemotherapy (AC) has proved to have beneficial effects in breast cancer treatment. However, DOX-based AC can have a damaging effect on the heart. This is often called DOX-induced cardiotoxicity (DIC). DIC is thought to be caused by inflammation and can lead to congestive heart failure (when the heart is unable to pump the blood effectively into the body).

Vitamin D (Vit D) has anti-inflammatory properties and has been linked to heart health. Low Vit D levels have been associated with heart disease. Animal studies have shown that Vit D supplementation improved markers associated with DIC. However, whether Vit D supplementation has protective effects on the heart health of patients with breast cancer receiving DOX-based AC is still unknown. 

The study included 150 women with breast cancer that were receiving 4 cycles of DOX-based AC. Patients were divided into two groups. Group 1 also received 0.5 µg Vid D tables daily during the course of the treatment. Group 2 did not receive Vit D supplements. Blood markers of heart toxicity such as lactate dehydrogenase (LDH), C troponin (CTrop), and interleukin-6 (IL-6) were measured before treatment and after 4 cycles of DOX AC.

After 4 cycles of DOX AC, group 1 had a significant increase in Vit D levels compared to the beginning of the study and compared to group 2. Group 2 had a decrease in Vit D levels compared to the beginning of the study.

After 4 cycles of DOX AC, there was a significant decrease (improvement) in inflammatory heart toxicity markers (LDH, CTrop, IL-6) in group 1 and an increase in these markers in group 2. There was also a significant decrease in these markers in group 1 compared to group 2. 

The study showed that individuals receiving DOX-based AC plus Vit D have decreased markers of DIC when compared to those who received AC alone.

This study had a small number of participants. Only a few markers of DIC were measured. Further studies are needed.