Breast Cancer Survivors Are at High Risk for Osteoporosis

PONTE VEDRA BEACH, Fla—Eighty percent of breast cancer
survivors were found to have osteoporosis or osteopenia at the outset of a
University of Nebraska Medical Center College of Nursing pilot study into
preventing osteoporosis among survivors.

Although breast cancer survivors are known to be at increased
risk for osteoporosis, the number with measurable bone loss was a surprise,
according to two researchers who presented preliminary findings at the Oncology
Nursing Society’s Sixth National Conference on Cancer Nursing Research.

Only 13 of the 30 postmenopausal participants had been screened
for bone loss before entering the feasibility study, which is testing whether
breast cancer survivors will comply with a regimen of weight training and
medication.

Nancy L. Walt-man, PhD, ARNP; Carol D. Ott, RN, PhD, OCN; and
their team of investigators at the University of Nebraska Medical Center
College of Nursing are looking for alternatives to hormone replacement therapy
(HRT) as an intervention for these women, who generally cannot take HRT (see related article).

Six of the initial subjects had osteoporosis and 18 had
osteopenia. Yet most had no idea that they had reason to be concerned about
osteoporosis, according to Dr. Ott, assistant professor at the college’s
Kearny campus. "They really hadn’t realized that they were at risk
because they had gone into menopause early," she told ONI in an
interview.

Dr. Ott reported that the women, ages 42 to 65, also had less
muscle strength than expected for their age groups, and that muscle strength
corresponded to bone density. "If muscle strength was low, bone density
was low," she said.

The researchers did not have data on muscle strength for
healthy women the age of the participants, but found that the breast cancer
survivors had less than half the mean muscle strength of younger adults. Normal
loss would have been 10% to 20%, Dr. Ott said. "These women came to us
pretty deconditioned," she added.

Preventive Regimen

The full regimen includes home-based strength/weight exercises
(see Figure), calcium, vitamin D, and alendronate (Fosamax), a bisphosphonate
used for the treatment and prevention of osteoporosis. The women had to do
eight different exercises—three arm exercises, three leg exercises, and two
balance exercises—twice a week. They received education about the disorder,
coaching, and feedback in monthly home visits and telephone calls.

Another 11 survivors were recruited for a control group that
did not do the exercises. This group has dropped to 7 women, and was actually
more difficult to recruit, Dr. Ott said, because the project did not have funds
to pay for their alendronate, which costs about $60 per month.

Six months into the study, 24 of the original 30 women were
still complying with the full regimen, said Dr. Waltman, associate professor at
the campus in Lincoln. Adherence hovered around 96%, and none of the women who
dropped out of the trial were dissatisfied with the intervention. Their reasons
included the cost of alendronate, personal reasons, a recurrence of breast
cancer, and normal bone density in the initial testing.

Retesting found that the regimen was paying off for those who
stuck with it. At 6 months, bone mass density improved from 0.85 to 0.86 g/cm²
for the hip and from 0.96 to 0.97 g/cm² for the spine. Bone mass
density in the forearm declined, however, from 0.52 to 0.49 g/cm².
The researchers are adding more exercises for the wrist and forearm to be
performed with heavier weights.

Along with increased bone density came increased muscle
strength and balance, Dr. Ott said. On a simple tandem balance test—how fast
the person can walk backwards for 20 feet—the experimental group went from 13
seconds to 10 seconds in the first 2 months. The balance component is
important, she emphasized, because preventing falls can prevent fractures.

While the project so far has shown that breast cancer survivors
can and will do weight-training exercises, the investigators are concerned that
many of the women seem to be content to increase their weights from 5 lb to 8
or 10 lb and then plateau, rather than advance to 20 lb, at which point they
would go on to exercise machines.

"We have found that many didn’t increase their weights
fast enough and high enough, and need to be pushed to keep increasing the
weights," Dr. Ott said.

The project will finish collecting 12-month results in
September, after which the researchers hope to go on to a larger study.

The funding sources for the study are the Oncology Nursing
Foundation, Regional West Medical Center Foundation, American Nurses
Foundation, and Sigma Theta Tau International.