Bone Loss Rx Didn't Lower Cancer Risk

Colorectal cancer risk reduction not associated with oral bisphosphonate use

(RxWiki News) It’s always exciting when researchers find a new benefit for an existing medication. One type of medicine that treats bone loss has been shown to have anti-cancer properties.

Medications that treat bone loss are called bisphosphonates. A new study has concluded that the use of oral bisphosphonates did not lower the risk of colorectal cancer.

The most commonly used medication in the study was Fosamax (alendronate).

"Stay physically active for strong bones."

Michael N. Passarelli, of the Public Health Sciences Division at Fred Hutchinson Cancer Research Center in Seattle, WA, was the lead investigator of this study, which reviewed patient records from the large Women’s Health Initiative (WHI) clinical trials.

The goal of the study was to determine if oral bisphosphonate use was associated with lower risks of colorectal cancer.

Results of previous studies looking at this question have been inconsistent. One study found a 60 percent reduced risk of colorectal cancer among bisphosphonate users. Other studies found more modest risk reductions, and one study found no association.

For this study, researchers looked at the associations between oral bisphosphonate use and colorectal cancer in 156,826 postmenopausal women who participated in WHI study. The participants were 50 to 79 years of age.

Researchers conducted in-depth health interviews at the time the women were enrolled. Medications the women used, including oral bisphosphonates, were recorded at the beginning of the study and tracked during follow-up.

Among the women who used oral bisphosphonate​s, 90 percent took Fosamax.

Of all the women who participated in the WHI study, a total of 1,931 were diagnosed with invasive colorectal cancer during follow-up, which lasted a median of 12 years. These statistics indicate that about 1 percent of the study population developed colorectal cancer.

“We did not find sufficient evidence to conclude that there was a meaningful association between bisphosphonate use and colorectal cancer risk in WHI. If any association exists, it may be smaller than what our study could detect,” the authors wrote.

The length of time the women took the medications did not affect these findings.

Oral bisphosphonates have been associated with a roughly 30 percent decreased breast cancer risk in several studies, including WHI. However, these medications have been shown to increase the risks of serious side effects including thigh bone (femur) fractures and jaw bone death.

This study was published in the March issue of the Journal of Bone and Mineral Research. One of the authors, Rowan T. Chlebowski, has served as a paid consultant for AstraZeneca and has received honoraria from AstraZeneca, Novartis and Amgen. No other conflicts of interest were disclosed.

Review Date: 
March 20, 2013