SAN ANTONIO — Current American Society of Clinical Oncology guidelines for maintenance of bone health in breast cancer patients are outdated and do not sufficiently protect against fractures, a prominent European expert asserted at the San Antonio Breast Cancer Symposium.
“Nothing against ASCO, but their guidelines were developed in 2002 and published in 2003. Back then people in the osteoporosis field thought bone mineral density was the main contributor to fracture risk, so the ASCO guidelines restrict bisphosphonate therapy to breast cancer patients with a T score of −2.5 or less,” said Dr. Peyman Hadji, professor of endocrinology and reproductive medicine at Philipps University of Marburg (Germany).
“The osteoporosis world has turned around since then. We don't treat T scores anymore, we treat absolute fracture risk. We calculate the absolute risk of a hip or spinal fracture in the next 10 years based on the T score and also using clinical risk factors,” he continued.
Dr. Hadji is the lead author of a contemporary alternative set of evidence-based guidelines developed by expert panel consensus (Ann. Oncol. 2008;19:1407-16).
Those guidelines significantly lower the threshold for bisphosphonate therapy (see sidebar).
“In Europe, these guidelines have had a big uptake. They're very easy for gynecologists and oncologists to use,” he said.
But physicians keep asking me, 'What proportion of breast cancer patients do we have to treat?' Their big fear was they'd have to give [zoledronic acid] to everyone on an aromatase inhi-?bitor. That's why we did this new study,” he explained in an interview.
He reported on 402 postmenopausal women with hormone receptor-positive breast cancer on tamoxifen or an aromatase inhibitor. This group of women had a calculated 10-year fracture risk of about 25%.
Yet under the ASCO guidelines (J. Clin. Oncol. 2003;21:4042-57), which recommend antiresorptive therapy in patients with a T score of −2.5 or lower, only 9% of the women would have qualified. In contrast, under the new guidelines, which call for treatment initiation in the presence of two or more risk factors, 29% of patients were bisphosphonate eligible.
To estimate how many fractures would be prevented in postmenopausal women with hormone receptor-positive breast cancer, Dr. Hadji and his coinvestigators turned to the 150,000-woman-strong database for the National Osteoporosis Risk Assessment study.
Using the ASCO guidelines to initiate bisphosphonate therapy in 9% of patients, only 18% of fractures would be prevented. Using the guidelines developed by Dr. Hadji and his associates, roughly 29% of women would be treated and at least 45% of fractures would be prevented. And that 45% figure is probably an underestimate, since women with breast cancer have a higher fracture risk than do healthy age-matched controls, Dr. Hadji said.
“This again indicates that restricting the risk assessment to bone mineral density is not good enough to identify the women at highest risk of fracture. Until ASCO comes out with new guidelines similar to ours, ours are much superior,” he declared.
The multidisciplinary international panel that joined Dr. Hadji in developing the guidelines for prevention and management of aromatase inhibitor-associated bone loss included Dr. Adam M. Brufsky of the University of Pittsburgh Cancer Institute, Dr. Theresa A. Guise, an endocrinologist at the University of Virginia, Charlottesville, and Dr. Allan Lipton, a medical oncologist at Pennsylvania State University, Hershey.
The guideline-development project was funded by Novartis. Dr. Hadji disclosed that he has received honoraria, unrestricted educational grants, and research funding from Novartis and a dozen other pharmaceutical companies.
'Until ASCO comes out with new guidelines similar to ours, ours are much superior.' DR. HADJI
Who Gets the Bisphosphonate?
The new practical guidelines recommend that all breast cancer patients on an aromatase inhibitor should receive calcium and vitamin D supplements, and that in addition, bisphosphonate therapy is warranted in those with any two of the following validated fracture risk factors:
▸ A T score below −1.5.
▸ Age greater than 65 years.
▸ History of oral corticosteroid use for longer than 6 months.
▸ Body mass index below 20 kg/m
▸ Family history of hip fracture.
▸ Positive smoking history.
▸ Personal history of a fragility fracture after age 50.
Source: Dr. Hadji