Parathyroid hormone-related peptide and survival of patients with cancer and hypercalcemia.
OBJECTIVE
Parathyroid hormone-related peptide (PTHrP) is the predominant cause of malignancy-associated hypercalcemia. However, its prognostic utility is unclear. We aimed to determine the prognostic value of serum PTHrP levels in patients who had hypercalcemia associated with malignancy.


METHODS
In this prospective case series, we evaluated 76 patients with a diagnosis of cancer and hypercalcemia (serum calcium level >/=10.3 mg/dL on at least two occasions). PTHrP levels >/=1 pmol/L were considered elevated. We used multivariate Cox regression analysis to identify factors associated with mortality.


RESULTS
Fifty patients (66%) died during follow-up. In a multivariate analysis, higher pretreatment calcium levels and elevated PTHrP levels were associated with increased mortality, with effects of PTHrP varying by age (P = 0.03). Survival was associated with pretreatment calcium levels both in patients over 65 years of age (hazard ratio [HR] per mg/dL = 1.5; 95% confidence interval [CI]: 1.2 to 1.8; P <0.001) and in patients aged 65 years or less (HR = 1.3; 95% CI: 1.1 to 1.5; P = 0.003). Adjusted for pretreatment calcium levels, elevated PTHrP levels were associated with increased mortality in patients aged </=65 years (HR = 3.8; 95% CI: 1.6 to 8.8; P = 0.002), but not in older patients (HR = 0.7; 95% CI: 0.3 to 1.9; P = 0.51).


CONCLUSIONS
PTHrP is a useful prognostic factor in malignancy-associated hypercalcemia, at least in patients aged </=65 years.
Truong
Ngoc Uyen
NU
Department of Medicine, Royal Victoria Hospital, Montreal, Canada.
deB Edwardes
Michael D
MD
Papavasiliou
Vasilios
V
Goltzman
David
D
Kremer
Richard
R
D015415:Biomarkers / Q000097:blood; D015897:Comorbidity; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009369:Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000401:mortality*; D044162:Parathyroid Hormone-Related Protein; D036361:Peptide Hormones / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012016:Reference Values; D016019:Survival Analysis
D015415:Biomarkers; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D036361:Peptide Hormones