Calcitriol production in hypercalcemic and normocalcemic patients with non-Hodgkin lymphoma.
OBJECTIVE
To determine the following: a reference range for serum calcitriol during hypercalcemia in a control group of patients with myeloma in whom calcitriol production is known to be appropriately suppressed; the incidence of elevated serum calcitriol levels in hypercalcemic patients with non-Hodgkin lymphoma according to this derived reference range; and the incidence of abnormal calcium metabolism in normocalcemic patients with non-Hodgkin lymphoma.


METHODS
Prospective clinical study.


METHODS
Referral cancer center.


METHODS
2 groups of hypercalcemic patients: 16 control patients with myeloma and 22 patients with non-Hodgkin lymphoma divided into those with elevated or normal serum calcitriol levels; 1 group of 22 normocalcemic patients with non-Hodgkin lymphoma.


METHODS
Serum chemistries and intact parathyroid hormone, calcitriol, parathyroid hormone-related protein, and urinary electrolyte levels.


RESULTS
On the basis of the mean serum calcitriol level of the control group plus 3 standard deviations, the reference range for serum calcitriol during hypercalcemia was defined as less than 42 pg/mL. Although serum calcium and parathyroid hormone levels in the study patients were similar to those in controls, 12 of the 22 hypercalcemic patients with non-Hodgkin lymphoma (55%) had serum calcitriol levels greater than 42 pg/mL (range, 51 to 170 pg/mL). No features distinguished the patients with elevated serum calcitriol levels from those with normal levels. Seventy-one percent of normocalcemic patients with non-Hodgkin lymphoma were hypercalciuric, and 18% had serum calcitriol levels greater than the normocalcemic reference range (20 to 76 pg/mL).


CONCLUSIONS
Serum calcitriol levels are elevated in most hypercalcemic patients with non-Hodgkin lymphoma in the absence of elevated serum levels of parathyroid hormone, which implicates extrarenal calcitriol production in the pathogenesis of this syndrome. Abnormal calcium metabolism, hypercalciuria, and dysregulated calcitriol production are also common in normocalcemic patients with non-Hodgkin lymphoma.
Seymour
J F
JF
Royal Melbourne Hospital, Victoria, Australia.
Gagel
R F
RF
Hagemeister
F B
FB
Dimopoulos
M A
MA
Cabanillas
F
F
D000328:Adult; D000368:Aged; D002117:Calcitriol / Q000096:biosynthesis / Q000097:blood* / Q000652:urine; D002118:Calcium / Q000097:blood* / Q000652:urine; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood* / Q000209:etiology / Q000652:urine; D016393:Lymphoma, B-Cell / Q000097:blood; D016403:Lymphoma, Large B-Cell, Diffuse / Q000097:blood; D008228:Lymphoma, Non-Hodgkin / Q000097:blood* / Q000150:complications / Q000652:urine; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D044162:Parathyroid Hormone-Related Protein; D011446:Prospective Studies; D011506:Proteins / Q000378:metabolism
D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D002117:Calcitriol; D002118:Calcium