Background/aims: The present study was conducted to investigate the relationship between bone metabolic disorder after gastrectomy for gastric cancer and vitamin D metabolites or the hormones involved in calcium metabolism.
Methodology: Twenty-one patients who had undergone gastrectomy for gastric cancer and had been followed for less than 10 years were assessed for bone disorder by microdensitometry. The levels of 1,25-dihydroxy vitamin D (1,25(OH)2VD), 25-hydroxy vitamin D (25(OH)VD), 24,25-dihydroxy vitamin D (24,25(OH)2VD), N-PTH, calcitonin, estradiol, osteocalcin, and ALP were measured and assessed for correlations with clinicopathological factors, including the operative procedure and the number of years since surgery.
Results: Bone disorder was found in 9 out of 21 patients (42.9%). The prevalence was significantly higher in patients who had undergone surgery more than 2 years before assessment, so there was a relationship between the period after surgery and bone disorder. Among the vitamin D metabolites, the level of 1,25(OH)2VD was normal in all patients, whereas 25(OH)VD was reduced in 6 out of 21 patients (28.6%) and 24,25(OH)2VD was reduced in 17 patients (81.0%). The 1,25(OH)2VD was significantly higher in the patients with Grade I to III bone disorder compared to the patients with normal bones or early bone disease. The 1,25(OH)2VD/25(OH)VD ratio was significantly higher in the patients without passage of food through the duodenum due to the reconstructive method, while the 25(OH)VD/24,25(OH)2VD ratio was significantly higher in the patients with remaining of duodenal food passage. PTH was decreased in about 50% of the patients, while calcitonin was normal in all patients. Estradiol was decreased in one female patient, while it was elevated in 10 of the 17 men (58.8%). The osteocalcin level was high in all patients irrespective of the period after surgery.
Conclusions: After gastrectomy, the incidence of bone metabolic disorder increases with time. Changes of vitamin D metabolites, particularly 25(OH)VD and 24,25(OH)2VD, seem to be closely associated with post-gastrectomy bone disease.