An update of the phase III trial comparing whole pelvic to prostate only radiotherapy and neoadjuvant to adjuvant total androgen suppression: updated analysis of RTOG 94-13, with emphasis on unexpected hormone/radiation interactions.
OBJECTIVE
This trial was designed to test the hypothesis that total androgen suppression and whole pelvic radiotherapy (WPRT) followed by a prostate boost improves progression-free survival (PFS) by > or =10% compared with total androgen suppression and prostate only RT (PORT). This trial was also designed to test the hypothesis that neoadjuvant hormonal therapy (NHT) followed by concurrent total androgen suppression and RT improves PFS compared with RT followed by adjuvant hormonal therapy (AHT) by > or =10%.


METHODS
Patients eligible for the study included those with clinically localized adenocarcinoma of the prostate and an elevated prostate-specific antigen level of <100 ng/mL. Patients were stratified by T stage, prostate-specific antigen level, and Gleason score and were required to have an estimated risk of lymph node involvement of >15%.


RESULTS
The difference in overall survival for the four arms was statistically significant (p = 0.027). However, no statistically significant differences were found in PFS or overall survival between NHT vs. AHT and WPRT compared with PORT. A trend towards a difference was found in PFS (p = 0.065) in favor of the WPRT + NHT arm compared with the PORT + NHT and WPRT + AHT arms.


CONCLUSIONS
Unexpected interactions appear to exist between the timing of hormonal therapy and radiation field size for this patient population. Four Phase III trials have demonstrated better outcomes when NHT was combined with RT compared with RT alone. The Radiation Therapy Oncology Group 9413 trial results have demonstrated that when NHT is used in conjunction with RT, WPRT yields a better PFS than does PORT. It also showed that when NHT + WPRT results in better overall survival than does WPRT + short-term AHT. Additional studies are warranted to determine whether the failure to demonstrate an advantage for NHT + WPRT compared with PORT + AHT is chance or, more likely, reflects a previously unrecognized biologic phenomenon.
Lawton
Colleen A
CA
Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI 53226, USA. clawton@randoc.mcw.edu
DeSilvio
Michelle
M
Roach
Mack
M
Uhl
Valery
V
Kirsch
Robert
R
Seider
Michael
M
Rotman
Marvin
M
Jones
Christopher
C
Asbell
Sucha
S
Valicenti
Richard
R
Hahn
Stephen
S
Thomas
Charles R
CR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D003131:Combined Modality Therapy / Q000379:methods; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology; D018714:Radiotherapy, Adjuvant
D000726:Androgen Antagonists; D017430:Prostate-Specific Antigen