Pion conformal radiation of prostate cancer: results of a randomized study.
OBJECTIVE
To compare the efficacy of pion radiation therapy with conventional external beam photon therapy, for the treatment of locally advanced stage T3/4, N0, M0 adenocarcinoma of the prostate.


METHODS
Two hundred seventeen eligible patients were randomly allocated to either photon or pion therapy. No adjuvant hormone therapy was used.


RESULTS
Median follow-up was 42 months (range 2-90). Acute bladder toxicity was worse in the pion arm, p = 0.2, but other acute toxicity did not differ. Late grade 2 toxicity was significantly less in the pion arm (29% at 5 years versus 48%, p = 0.002), but late grade 3 or 4 toxicity did not differ. Clinical local control was not significantly different between treatment arms (64% after 5 years with photons, 56% with pions, p = 0.6). Cause-specific and overall survival also did not differ (p = 0.7). There was a significant delay in time to first failure in the photon arm, largely as a result of decreased biochemical relapse, p = 0.01. A multivariate analysis is presented.


CONCLUSIONS
Pion therapy was well tolerated, with increased acute toxicity and significantly decreased late tissue injury. This contrasts with the late toxicity observed with higher LET particle therapy such as neutron therapy. No improvement in local control with pion therapy was observed.
Pickles
T
T
Radiation Oncology Program, BC Cancer Agency, Vancouver, Canada.
Goodman
G B
GB
Fryer
C J
CJ
Bowen
J
J
Coldman
A J
AJ
Duncan
G G
GG
Graham
P
P
McKenzie
M
M
Morris
W J
WJ
Rheaume
D E
DE
Syndikus
I
I
D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008651:Mesons / Q000627:therapeutic use*; D008875:Middle Aged; D009367:Neoplasm Staging; D017785:Photons / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011788:Quality of Life; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*