Data-driven Cancer Research Conference 2026

1.Background

• Pelvic radiotherapy is associated with insufficiency fractures and long-term morbidity.

•

• Relationship of dose and bone mineral density (BMD) loss is poorly defined.

•

• Prospective DXA-based studies are rare, limiting evidence-based bone health guidance.

•

RadBoneis the first prospective randomised pilot study to:

1.Quantify vertebral dose-response for radiation-induced BMD loss.

●

2. Assess feasibility and effect of a musculoskeletal health package (MHP).

2. Methods

Study design

•Pilot study of 26 women receiving pelvic radiotherapy (cervical n=9, endometrial n=13, anorectal n=4).

•

•Participants randomised to MHP (n=11; prehabilitation exercise, calcium and vitamin D supplementation) or observation (n=15)

•

•L1–L4 BMD measured by DXA at baseline and 18 months; %ΔBMD calculated per vertebra.

3. Results

Dose-response

No significant dose-response in full cohort

Significant linear dose–response in subgroup with D50 > 5Gy: -0.2% ΔBMD per Gy (? = -0.19, p < 0.001; Figure 1, Table 1)

Intervention effect

Median ∆BMD: -3.3% (IQR -7.3 to +1.5)

MHP patients showed significantly better BMD preservation (-1.25% vs -3.80%, p = 0.0045, Figure 2)

Adjusting for MHP did not alter dose-response relationship (Table 2)

4. Conclusions

Significant dose-response observed between vertebral dose and BMD decline, with threshold near 5Gy.

MHP participants showed greater bone preservation than controls.

Multicentre studies are needed to validate results.

Findings could inform future bone-sparing strategies in treatment planning.

Data-driven Cancer Research Conference 2026

Exploring dose-response relationships in vertebral bone loss after pelvic radiotherapy: The prospective RadBone trial

Poster Presenter

Authors

Affiliations

Part of Topic

Comments