Study finds link between osteoporosis and osteoporosis treatment and a reduced risk of breast cancer recurrence

03 June 2012

Toronto -

New research presented today draws a significant link between the development of osteoporosis, osteoporosis treatment and a reduced risk of breast cancer recurrence.

The study was one of a total of 20 abstracts to be presented by the NCIC Clinical Trials Group (CTG) at the American Society of Clinical Oncology (ASCO) meeting in Chicago. The meeting is considered to be the premier scientific event for oncology professionals. The presentations focus on new ways to treat a variety of cancers including breast, colorectal, lung and prostate.

Today’s ASCO presentation is an exploratory study within a completed large clinical trial, which involved more than 7,000 postmenopausal breast cancer patients. The objective of the original trial was to compare the use of two aromatase inhibitors (AIs) – exemestane and anastrozole – as adjuvant therapy to determine which was more effective at preventing recurrence of the disease. Adjuvant therapy is used after initial treatment for cancer.

The clinical trial found that both drugs were equally effective in preventing recurrence. However, while AIs are the drug of choice for preventing breast cancer recurrence, they can lead to the loss of bone density and lead to osteoporosis.

The study presented today involved almost 1,300 postmenopausal women with a diagnosis of early breast cancer who used AIs and who had osteoporosis. The researchers found that the women with osteoporosis experienced improved event-free survival (how effective a treatment is at preventing recurrence) and distant disease-free survival (a measure of how long patients remain free of metastasis at distant sites), pointing to the need to weigh the risks and benefits of treatment with AIs.

The researchers went on to study the use of bisphosphonates (a class of drugs used to prevent the loss of bone mass and treat osteoporosis and similar diseases) along with other factors and their impact on the recurrence of breast cancer. Thirty-six percent of women in the original clinical trial were on some form of therapy to either prevent or treat osteoporosis at the time they were randomized to the trial, or started treatment during the course of the trial.

“While this is an exploratory study, the results suggest that the treatments used by thousands of women to prevent or treat osteoporosis may actually have a bigger role than just promoting bone health,” says study lead Dr. Lois Shepherd. “In other words, preventing the deterioration in bone health, as a result of treatment with AIs, may have an additional positive effect in reducing the risk of breast cancer recurrence.”

This presentation has been selected as one of the Best of ASCO. Of the thousands of research abstracts that are submitted for presentation, about 1% is deemed to be Best of ASCO. Research in this category is considered to be the best with potential to change how cancer is treated.

This presentation is one of several being presented at the conference that was conducted by or included participation of the NCIC Clinical Trials Group, which is supported by core funding from the Canadian Cancer Society. The NCIC CTG is a highly respected research group that develops, conducts and analyzes national and international trials of cancer prevention, treatment and supportive care. The CTG has led trials that have changed clinical practice across Canada and around the world.

The American Society of Clinical Oncology annual meeting is considered the premier educational and scientific event in the clinical cancer research community. It attracts more than 25,000 researchers from all over the world.

 Read about previous NCIC CTG presentations at ASCO

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For more information, please contact:

Christine Harminc

Senior Manager, Communications & Media Relations

Canadian Cancer Society

Phone: 416 934-5340