Neutron irradiation of human pelvic tissues yields a steep dose-response function for late sequelae.
OBJECTIVE
Analysis of the dose-response function in normal tissues following pelvic irradiation for carcinoma of the prostate.


METHODS
A homogeneous group of 136 patients with locally advanced carcinoma of the prostate were treated with the Fermilab high-energy neutron beam at three dose levels: 19, 20.4, and 21 Gy, using the same treatment plan and fractionation scheme for all patients.


RESULTS
Tumor control rates were about 83% at the three dose levels studied. However, the normal tissue complication rate (late sequelae) varied with dose: 0 out of 5 at 19 Gy, 5 out of 58 (8.6%) at 20.4 Gy, and 9 out of 73 (12.3%) at 21 Gy.


CONCLUSIONS
Neutron therapy to the pelvis reveals a steep dose-response function for late effects with a coefficient of variation of only 11%. This is lower than that usually observed with photons or with less uniform clinical data sets, and may be characteristic for well-planned high-LET radiotherapy.
Cohen
L
L
Midwest Institute for Neutron Therapy at Fermilab, Batavia, IL 60510, USA.
Saroja
K R
KR
Hendrickson
F R
FR
Lennox
A J
AJ
Hatcher
M A
MA
Kroc
T K
TK
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009502:Neutrons / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011882:Radiotherapy, High-Energy