title: Is the risk of primary hyperparathyroidism increased in patients with untreated breast cancer?
abstract: BACKGROUND
  An increased frequency of primary hyperparathyroidism (PHP) has been reported in patients with treated breast cancer (BC). PHP has been found in about 7% of BC patients after surgery and radio-, chemio- or hormonal therapy.
  
  
  OBJECTIVE
  To evaluate the frequency of PHP in untreated BC patients.
  
  
  METHODS
  We evaluated 186 women with BC and 233 women with thyroid cancer (TC, no.=122) or benign thyroid diseases (BTD, no.=111). In all patients, serum calcium, albumin, PTH, and 25-hydroxyvitamin D (25-OH vitD) were measured before any treatment.
  
  
  RESULTS
  Serum calcium concentrations were significantly higher in BC than in TC and BTD groups (median values 9.5 mg/dl, 9.3 mg/dl and 9.3 mg/dl, respectively) but, according to a logistic regression model, calcium was not significantly different between the 3 groups when age was taken into account. In all patients, serum calcium was in the normal range, indicating that no case of overt PHP was present. Five patients (1 in BC, 2 in TC, and 2 in BDT groups) had serum calcium close to the upper limit of normal range, high PTH and low 25-OH vitD, indicating a possible PHP with hypercalcemia masked by concomitant 25-OH vitD deficiency.
  
  
  CONCLUSIONS
  In untreated BC group, no patient had overt PHP and 1/186 (0.5%) presented a possible PHP masked by 25-OH vitD deficiency, a PHP frequency much lower than that observed in treated BC patients. These data suggest that the treatments of BC may be responsible for the increased frequency of PHP reported in previous studies.
authors.affiliation: Department of Endocrinology and Metabolism, University of Pisa, Via Paradisa 2, 56124 Pisa, Italy. valentina.belardi@alice.it
authors.forename: V
authors.initials: V
authors.lastname: Belardi
authors.forename: E
authors.initials: E
authors.lastname: Fiore
authors.forename: E
authors.initials: E
authors.lastname: Giustarini
authors.forename: I
authors.initials: I
authors.lastname: Muller
authors.forename: S
authors.initials: S
authors.lastname: Sabatini
authors.forename: V
authors.initials: V
authors.lastname: Rosellini
authors.forename: E
authors.initials: E
authors.lastname: Seregni
authors.forename: R
authors.initials: R
authors.lastname: Agresti
authors.forename: C
authors.initials: C
authors.lastname: Marcocci
authors.forename: P
authors.initials: P
authors.lastname: Vitti
authors.forename: C
authors.initials: C
authors.lastname: Giani
mesh_terms: D000236:Adenoma / Q000097:blood / Q000150:complications; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000097:blood / Q000150:complications*; D002118:Calcium / Q000097:blood; D005260:Female; D006044:Goiter, Nodular / Q000097:blood / Q000150:complications; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000150:complications / Q000453:epidemiology*; D007558:Italy / Q000453:epidemiology; D016015:Logistic Models; D008875:Middle Aged; D012306:Risk; D013964:Thyroid Neoplasms / Q000097:blood / Q000150:complications
chemical_list: D002118:Calcium