Effect of Pelvic Irradiation on the Bone Mineral Content of Lumbar Spine in Cervical Cancer / 대한치료방사선과학회지

ABSTRACT

PURPOSE: To evaluate the loss of bone mineral contents(BMC) in lumbar spine within the radiation field for cervical cancer treatment, BMC in the irradiated patient group was compared with that of a normal control group. METHOD AND MATERIALS Measurements of BMC in the trabecular bone in lumbar spines(L3-L5) were performed in the both patient and normal control groups. Investigators used dual-energy quantitative computerized tomography(DEQCT) using photon energy of 120 and 80kVp. The numbers of patient and control groups were 43 in each with age distribution of fifth to seventh decade of women. The numbers of control group were 22 in fifth, 10 in sixth, and 11 in seventh decade, those of patient group were 14 in fifth, 14 in sixth, and 15 in seventh decade of women. The radiation field was extended to L5 spine for pelvic irrdiation with 45-54Gy of external radiation dose and 30Gy of high dose rate brachytherapy in cervical cancer. RESULTS: The BMC is decreased as increasing age in both control and patient groups. BMC in lumbar spine of patient group was decreased by about 13% to 40% maximally. The BMC of L3 and L4 a region that is out of a radiation field for the patient group demonstrated 119.5+/-30.6, 117.0+/-31.7 for fifth, 83.3+/-37.8, 88.3+/-46.8 for sixth and 61.5+/-18.3, 56.2+/-26.6mg/cc for seventh. Contrasted by the normal control group has shown 148.0 +/-19.9, 153.2+/-23.2 for fifth, 96.1+/-30.2, 105.6+/-26.5 for sixth and 73.9+/-27.9, 77.2+/-27.2mg/cc for seventh decade, respectively. The BMC of patient group was decreased as near the radiation field, while the lower lumbar spine has shown more large amounts of BMC in the normal control group. In particular, the BMC of L5 within the radiation field was significantly decresed to 33%, 31%, 40% compared with the control group of the fifth, sixth and seventh decades, respectively. CONCLUSION: The pelvic irradiation in cervical cancer has much effected on the loss of bone mineral content of lumbar spine within the radiation field, as the lower lumbar spine has shown a smaller BMC in patient group with pelvic irradiation in contrast to that of the normal control groups.