Osteoporosis development and vertebral fractures after abdominal irradiation in patients with gastric cancer

BACKGROUND: Decrease in bone mineral density, osteoporosis development, bone toxicity and resulting insufficiency fractures as late effect of radiotherapy are not well known. Osteoporosis development related to radiotherapy has not been investigated properly and insufficiency fractures are rarely reported for vertebral bones. METHODS: Ninety-seven patients with gastric adenocarcinoma were evaluated for adjuvant treatment after surgery. While 73 out of 97 patients treated with adjuvant chemoradiotherapy comprised the study group, 24 out of 97 patients with early stage disease without need of adjuvant treatment comprised the control group. Bone mineral densities (BMD) of lumbar spine and femoral neck were measured by dual energy x-ray absorptiometry after surgery, and one year later in both groups. RESULTS: There was statistically significant decline in BMDs after one year in each group itself, however the decline in BMDs of the patients in the irradiated group was more pronounced when compared with the patients in the control group; p values were 0.02 for the decline in BMDs of lumbar spine, and 0.01 for femoral neck respectively. Insufficiency fractures were observed only in the irradiated patients (7 out of 73 patients) with a cumulative incidence of 9.6%. CONCLUSIONS: Abdominal irradiation as in the adjuvant treatment of gastric cancer results in decrease in BMD and osteoporosis. Insufficiency fracture risk in the radiation exposed vertabral bones is increased. Calcium and vitamin D replacement and other measures for prevention of osteoporosis and insufficiency fractures should be considered after abdominal irradiation.