Washington: A form of vitamin D has been found to greatly enhance radiation treatment for tumours associated with breast cancer. The findings support the potential benefits of combining a vitamin D analog with radiation to wipe out radiation-resistant cancer cells.

While radiation therapy is a common course of treatment after a malignant tumour is surgically removed, there are often cells that are resistant to radiation and may cause a recurrence of cancer.

When combined with radiation, the vitamin D analog EB 1089 is capable of wiping out radio-resistant cells that may be present following the surgical removal of a tumour in a clinical situation, according to a new collaborative Dartmouth Medical School study.

The study, published in the latest issue of the 'Journal of Clinical Cancer Research', compares tumour growth in mice treated with radiation alone and mice exposed to radiation and EB 1089, a derivative of vitamin D. Final tumour volume in animals irradiated with EB 1089 was approximately 50 per cent lower than in the group that received radiation alone.

"The results of our latest study with EB 1089 are very encouraging. The vitamin D analog has proven effective in enhancing radiation treatments in our prior studies with cell cultures and now in live mice. We are eager to push ahead to clinical trials with breast cancer treatments in humans," said lead author Dr Sujatha Sundaram, assistant research professor at Dartmouth Medical School.

Radiotherapy is commonly used to treat breast cancer, both before surgery to reduce tumour size and after surgery to reduce tumour recurrence. There has been increasing evidence that vitamin D – naturally manufactured by the body after exposure to sunlight – helps to prevent and treat several forms of cancer. But too much vitamin D has been found to induce excessive calcium that can affect bone metabolism and structure.

The vitamin D analog EB 1089 has a modified chemical structure, which has significantly, fewer calcium- related side effects. "It is relatively non toxic, especially when compared to chemotherapy treatments that cause hair loss, loss of appetite and several other side-effects," Sundaram noted.

ANI