Risk factors for rib fracture:
(1) female gender
(2) close location between tumor and chest wall (Asai et al use < 2 cm, the closer the tumor to the chest wall the more likely it will be included in the kill zone)
(3) older age (Taremi et al)
(4) maximum dose (Asai et al, Voroney et al)
(5) high-dose volume involving chest wall (Asai et al, Bongers et al)
Additional factors to consider:
(1) concurrent osteoporosis (affected by gender and age, above).
(2) low-energy trauma, including cough
The pain associated with a rib fracture may be much less than expected and may go uncrecognized clinically.
It is important not to mistake rib fracture from SBRT for pathologic fracture from metastatic carcinoma.
