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Bone Loss Associated With Leukemia Therapy Occurs Sooner Than Previously Thought

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Key Points

  • Using quantitative computed tomography (QCT), researchers determined that leukemia did not dramatically alter the properties of bone before chemotherapy.
  • During the 30-day induction phase, however, bone mineral density of the lower spine decreased by more than 25%, with significant thinning of the dense cortex occurring in the bones of the leg.
  • Researchers also measured bone mineral density using the older but more widely available technique of dual-energy x-ray absorptiometry and found that it underestimated these changes as compared to QCT measurements.

Investigators at Children’s Hospital Los Angeles (CHLA) have found that significant bone loss occurs during the first month of chemotherapy for acute lymphoblastic leukemia (ALL), which is far earlier than previously assumed. Results of the study were published by Orgel et al in the journal Bone.

ALL is the most common pediatric cancer. Forty years ago, only one in five children survived the disease. With the development of powerful chemotherapies, over 90% of patients can now expect to be cured. Unfortunately, significant side effects of these life-saving therapies include loss of bone density, resulting in an increased risk for bone fractures during and even after therapy. Previous studies to determine the changes to bone density during ALL therapy had focused on the cumulative effects of chemotherapy after months or even years of treatment.

“In clinic, we would see patients with fractures and vertebral compression during the very first few weeks of treatment,” said Etan Orgel, MD, MS, Attending Physician in the Survivorship & Supportive Care Program at the Children’s Center for Cancer and Blood Diseases at CHLA. “But we were unaware of any study that specifically examined bone before chemotherapy and immediately after the first 30 days of treatment—which would allow us to understand the impact of this early treatment phase.”

Study Findings

In a prospective study in newly diagnosed patients 10 to 21 years of age, the investigators explored leukemia-related changes to bone at diagnosis, and then the subsequent effects of the induction phase of chemotherapy. Using quantitative computed tomography (QCT)—a newer technique that has proven more accurate for use in growing bone—they determined that leukemia did not dramatically alter the properties of bone before chemotherapy (in comparison to similar age- and sex-matched control patients).

During the 30-day induction phase, however, bone mineral density of the lower spine decreased by more than 25%, with significant thinning of the dense cortex occurring in the bones of the leg. To help clinicians relate to these findings, the team also measured bone mineral density using the older but more widely available technique of dual-energy x-ray absorptiometry and found that it underestimated these changes as compared to QCT measurements.

“Now that we know how soon bone toxicity occurs, we need to reevaluate our approaches to managing these changes and focus research efforts on new ways to mitigate this common—yet significant—adverse effect,” said Steven Mittelman, MD, PhD, Principal Investigator at The Saban Research Institute of CHLA.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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