The research, published in Breast Cancer Research and Treatment, reports that patients receiving a weekly dose of 50,000 international units (IU), in addition to daily doses of 400IU of vitamin D reported significantly less musculoskeletal pain and also were less likely to experience pain that interfered with daily living whilst taking drugs, known as aromatase inhibitors, which commonly prescribed to shrink breast tumours.
“High-dose vitamin D seems to be really effective in reducing the musculoskeletal pain caused by aromatase inhibitors,” said Dr Antonella Rastelli, assistant professor at Washington University School of Medicine, who led the study.
“Patients who get the vitamin D weekly feel better because their pain is reduced and sometimes goes away completely. This makes the drugs much more tolerable. Millions of women worldwide take aromatase inhibitor therapy, and we may have another 'tool' to help them remain on it longer,” added Rastelli.
“It's great that we have something as simple as vitamin D to help patients alleviate some of this pain … It's not toxic - it doesn't cause major side effects. And if it is actually protecting against bone loss, that's even better,” she said.
Aromatase inhibitors are prescribed to shrink breast tumours that are fueled the hormone estrogen, and help prevent cancer recurrence. They are often prescribed to post-menopausal women for at least five years, and sometimes longer, after a breast cancer diagnosis.
The treatment is less toxic than chemotherapy, but for many patients, can lead to severe musculoskeletal discomfort, including pain and stiffness in the hands, wrists, knees, hips, lower back, shoulders and feet.
“About half of patients can experience these symptoms,” said the authors.
“We don't know exactly why the pain occurs, but it can be very debilitating … to the point that patients decide to stop taking aromatase inhibitors,” they added.
Because the drugs reduce cancer recurrence, finding a way to help patients stay on them is important for long-term, relapse-free survival, said Rastelli.
Rastelli's colleague, Dr Marie Taylor, first noticed that patients on aromatase inhibitors who experienced this pain found some relief from high doses of vitamin D.
The researchers, then set up a study, and recruited 60 patients with low baseline vitamin D who reported pain and discomfort associated with aromatase inhibitors.
Half the group was randomly assigned to receive the recommended daily dose of vitamin D (400 international units) plus a 50,000-unit vitamin D capsule once a week. The other half received the daily dose of 400 units of vitamin D plus a weekly placebo.
The results revealed that the very high weekly dose of vitamin D helped to alleviate muscle and join pain associated with the breast cancer drug.
Rastelli and her colleagues concluded that vitamin D supplementation strategies for breast cancer patients on aromatase inhibitors should be further investigated.
Source: Breast Cancer Research and Treatment
Volume 129, Number 1, Pages 107-116, doi: 10.1007/s10549-011-1644-6
“Vitamin D and aromatase inhibitor-induced musculoskeletal symptoms (AIMSS): a phase II, double-blind, placebo-controlled, randomized trial”
Authors: A.L. Rastelli, M.E. Taylor, F. Gao, R. Armamento-Villareal, et al