Keywords:
Genital / Reproductive system female, Oncology, CT-Quantitative, Radiation therapy / Oncology, Demineralisation-Bone, Toxicity
Authors:
C. Godber, C. Clark, T. Diamond, R. Rahbari
DOI:
10.26044/ranzcr2023/C-154
Results
127 patients were identified as having received pelvic radiotherapy for gynaecological malignancies with curative intent at our centre from 2020-2023. Of these patients, 24 met the inclusion criteria.
The patients analysed were predominantly post-menopausal at diagnosis (21/24), non-smokers (19/24) with mean age of 63.2 (45-85) and ECOG of 0-2. Endometrial cancer was the most common primary site of malignancy (20/24). 18/24 underwent chemotherapy as part of their treatment, with 8 patients receiving carboplatin/paclitaxel prior to treatment and 10 patients receiving concurrent cisplatin with radiotherapy. The mean dexamethasone dose per week for patients receiving chemotherapy was 18.5mg. The mean time post treatment to follow up QCT was 6.2 (1.0-15.1) months. Of the 24 included patients, 9 treatment plans involved pelvis and para-aortic nodes while 15 involved pelvis only. A summary of patient details is demonstrated in Figure 1.
A significant BMD loss was noted for 20/24 (83.3%) patients at the lumbar spine and 13/24 (54.2%) at the left femoral neck. Figures 2 and 3 demonstrate the mean pre and post treatment BMD in the lumbar spine and left femoral neck for all patients. Across all patients, the mean change in BMD was -29.1% (95% CI [-17.7% to -40.6%]) in the lumbar spine and -4.1% (95% CI [-0.5% to -8.7%]) at the left femoral neck. Figure 4 demonstrates the mean pre and post BMD in subgroups according to radiation fields. The loss of lumbar spine BMD was significantly more pronounced (t(13) = 3.354, p = 0.05) when the treatment field extended above L4 (mean BMD change of -50.2%, 95% CI [-29.8% to -70.5%]) compared to treatment plans that extended to L4 or below (mean BMD change of -16.5%, 95% CI [-6.1% to -16.5%]). The mean dose to the third lumbar vertebrae was 15.8Gy. A significant correlation was demonstrated between radiotherapy dose and BMD change at the L3 vertebrae (r=-0.739, p>0.001), which is demonstrated in Figure 5. The mean dose to the left femoral head was 16.4Gy. There was no significant relationship demonstrated between mean radiation dose and the left femoral neck BMD loss (r =-0.2, p=0.30). Figure 6 demonstrates the relationship since RT and percentage BMD loss at the lumbar spine and femoral neck, however a strong correlation was not demonstrated in this study.