IMRT

Dose-volume constraints for IMRT: pelvic bone + plexus

 Baxter et al: 

Increased risk of pelvic fractures in elderly women  Holm et al (follow-up data Stockholm trials):   No reports on dose-response relationship:  max 45-50 Gy

5.3% femoral neck/pelvic fractures + hospitalization (vs 2.4% no RT)

 Sacral insufficiency fractures:  Rare but significant morbidity  Incidence: 3-7% 

Independent risk factors: osteoporosis, female gender, age > 60 years  No data on dose-response relationship  Lumbosacral plexus:  Tunio et al (cervical cancer) 8% grade 2 or more plexopathy  Prospective studies in rectal cancer are warranted

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