Hip stiffness following mixed conformal neutron and photon radiotherapy: a dose-volume relationship.
OBJECTIVE
To determine the relationship between dose, volume, and the incidence of hip stiffness in patients who received conformal neutron irradiation for prostate cancer.


METHODS
A series of dose-searching studies using neutron irradiation for prostate cancer were performed to determine the optimal dose, fraction size, field size, technique, and proportions of photon and neutron dose. Neutron doses ranged from 9 to 20 Gy and photon doses ranged from 0 to 38 Gy. Data were analyzed by using a hip stiffness grading scale.


RESULTS
Hip stiffness was recorded on follow-up examination in 30% of patients (40 out of 132) treated with fast neutrons or mixtures of fast neutron and photon radiation for prostate cancer. Hip stiffness was categorized as none (Grade 0, 92 patients), mild (Grade 1, 24 patients), moderate (Grade 2, 10 patients), or severe (Grade 3, 6 patients). The incidence of hip stiffness differed significantly by dose and volume in the five dose levels studied (p < 0.001).


CONCLUSIONS
By using a mixture of conformal neutron and photon irradiation and limiting the total neutron dose to less than 13 Gy, hip stiffness toxicity could be reduced to acceptable levels.
Chuba
P J
PJ
Department of Radiation Oncology, Wayne State University, Gershenson Radiation Oncology Center, Detroit, MI 48201-2097, USA.
Sharma
R
R
Yudelev
M
M
Duclos
M
M
Shamsa
F
F
Giacalone
S
S
Orton
C G
CG
Maughan
R L
RL
Forman
J D
JD
D000368:Aged; D004307:Dose-Response Relationship, Radiation; D006615:Hip / Q000528:radiation effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009502:Neutrons / Q000009:adverse effects*; D017785:Photons / Q000009:adverse effects*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage