Radiation-Related Fractures after Radical Radiotherapy for Cervical and Endometrial Cancers: Are There Any Differences?

In this study, we reviewed CT/MRI scans and studied the rates of radiation-related fractures in subjects treated for cervical cancer (CC, 63 subjects) by radical radiotherapy (RT) and in subjects treated for endometrial cancer (EC, 64 subjects) by radical surgery and RT. The differences between bone density measured in L1 on pretreatment CT, age and body mass index (BMI) were evaluated. Despite significant differences in RT total dose, age, BMI, etc., between both groups, the rate of radiation-related fractures was similar: 28.6% of CC versus 26.6% of EC subjects. CC subjects with fractures were significantly older (62.4 ± 10.1 vs. 49.0 ± 12.4 years; < 0.001), and their bone densities were significantly lower (106.3 ± 40.0 vs. 168.2 ± 49.5 HU; < 0.001); no difference in BMI was found. EC subjects with fractures were without significant difference in age but had significantly lower bone densities (103.8 ± 29.0 vs. 133.8 ± 42.3 HU; = 0.009) and BMIs (26.1 ± 4.9 vs. 31.8 ± 6.9 kg/m; = 0.003). Bone density strongly correlated with age (r = -0.755) only in CC subjects. Subjects with fractures from both groups had similarly low bone densities (106.3 ± 40.0 vs. 103.8 ± 29.0 HU; = 0.829); however, no correlation between bone density and BMI was found. The rate of radiation-related fractures in both groups was clearly associated only with low pretreatment bone density, reflecting osteoporosis.