[Prevalence of hypercalcemia in patients with lung cancer]

Although hypercalcemia is a serious and frequent complication of lung cancer, it is not commonly investigated in our country. We studied the prevalence of hypercalcemia in 90 random lung cancer patients from the Department of Pneumology, Escola Paulista de Medicina. The following histological types were found: 35 Squamous cells carcinomas (CEC), 30 Adenocarcinomas (AdenoCa), 11 Small cells carcinomas (CIPC), 2 Large cells carcinomas (TGC), 1 Carcinoid, 1 Mesothelioma, 2 Undifferentiated carcinomas, 1 Adenosquamous, 1 in situ carcinoma and 4 metastatic tumors. Ionized Ca (Ca-i) was measured in blood samples of all patients. Hyperparathyroidism was excluded by PTH and cAMP determinations in the hypercalcemic patients (Ca-i > 1.29 mmol/L). We found elevated levels of Ca-i (range = 1.30 to 2.0 mmol/L) in 18 patients (20%), being: 12 CEC (66.7%), 3 AdenoCa (16.7%), 2 CIPC (11.1%) and 1 TGC (5.6%). The PTH levels were low or suppressed in all 18 patients, but cAMP determinations were elevated in 6 out of 12 patients. Hypercalcemia is then a very frequent complication of lung cancer (20%), and PTH measurement was able to exclude a hyperparathyroidism in all cases studied.