Prognostic role of serum parathyroid hormone levels in advanced prostate cancer
patients undergoing zoledronic acid administration.
Author(s): Berruti A, Cook R, Saad F, Buttigliero C, Lipton A, Tampellini M, Lee KA, Coleman
RE, Smith MR.
Affiliation(s): Medical Oncology, Department of Clinical and Biological Sciences, University of
Turin, Azienda Ospedaliera San Luigi, Orbassano, Italy. alfredo.berruti@gmail.com
Publication date & source: 2012, Oncologist. , 17(5):645-52
BACKGROUND: Secondary hyperparathyroidism is frequent in prostate cancer patients
with bone metastases, and this condition is worsened by the administration of
potent bisphosphonates. Serum parathyroid hormone (PTH) elevation can impair the
efficacy of these drugs in terms of survival.
METHODS: The prognostic role of elevated serum PTH levels at baseline and after 3
months of zoledronic acid administration was assessed prospectively in 643 bone
metastatic prostate cancer patients enrolled in a prospective randomized,
placebo-controlled study.
RESULTS: On multivariate analysis, after adjusting for major prognostic factors
and bone turnover markers, elevated baseline serum PTH level was negatively
associated with overall survival (hazard ratio [HR], 1.448; 95% confidence
interval [CI], 1.045-2.006; p < .03) in zoledronic acid-treated patients but not
in placebo-treated patients. In patients with normal baseline PTH levels, there
was a trend but insignificant association between zoledronic acid administration
and a better survival outcome than with placebo (HR, 0.81; 95% CI, 0.65-1.01; p =
.065), whereas a trend in the opposite direction was observed in patients with
elevated PTH levels (HR, 1.45; 95% CI, 0.87-2.39; p = .151); interaction test, p
= .040. Elevated serum PTH level after 3 months of zoledronic acid treatment was
not significantly associated with survival outcome.
CONCLUSIONS: Secondary hyperparathyroidism has a negative prognostic impact in
metastatic prostate cancer patients undergoing zoledronic acid administration.
Counteracting elevated PTH levels by adequate doses of vitamin D may improve the
efficacy of this drug.
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