Long-term treatment sequelae after external beam irradiation with or without hormonal manipulation for adenocarcinoma of the prostate: analysis of radiation therapy oncology group studies 85-31, 86-10, and 92-02.
OBJECTIVE
Late gastrointestinal (GI) and genitourinary (GU) morbidity from external beam irradiation used to treat adenocarcinoma of the prostate continue to be a concern of physicians and patients alike. In addition, for locally advanced/high-risk cancer, the appropriate use of hormonal manipulation in addition to radiation therapy (RT) may increase toxicity. We analyzed three large Radiation Therapy Oncology Group (RTOG) studies (85-31, 86-10, and 92-02) to try to address these issues.


METHODS
A total of 2,922 patients were accrued with a median follow-up of 10.3 years for surviving patients. The RTOG scoring scheme was used to assess GI, GU, and other toxicities. Toxicity reported was Grade 3 or higher late toxicity. Patient toxicity level was assessed by study and by treatment type combining RT only vs. RT + short-course hormone therapy (STH) vs. RT + long-term hormone therapy (LTH).


RESULTS
Multivariate analysis reveals that age >70 was statistically significantly associated with a decrease in late any Grade 3+ toxicity (hazard ratio [HR] = 0.78, p = 0.0476) adjusted for treatment type. Comparing treatment type, patients treated with RT+STH had a statistically significant lower probability of Grade 3+ GI, GU, and other toxicity compared with RT alone (p = .00006; p = 0.0037; p = 0.0127, respectively). Patients treated with RT+LTH had a statistically significant lower probability of Grade 3+ GU toxicity compared with RT alone (p = 0.023).


CONCLUSIONS
These data show that external beam radiation therapy remains a safe option for locally advanced/high-risk prostate cancer, and the use of hormonal manipulation does appear to be protective for GU and GI toxicity depending upon length of treatment.
Lawton
Colleen A
CA
Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI 53226, USA. clawton@radonc.mcw.edu
Bae
Kyoungwha
K
Pilepich
Miljenko
M
Hanks
Gerald
G
Shipley
William
W
D000230:Adenocarcinoma / Q000097:blood / Q000188:drug therapy / Q000532:radiotherapy*; D000368:Aged; D000726:Androgen Antagonists / Q000627:therapeutic use; D003131:Combined Modality Therapy; D005485:Flutamide / Q000627:therapeutic use; D005500:Follow-Up Studies; D041981:Gastrointestinal Tract / Q000528:radiation effects*; D017273:Goserelin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology*; D014566:Urogenital System / Q000528:radiation effects*
D000726:Androgen Antagonists; D017273:Goserelin; D005485:Flutamide; D017430:Prostate-Specific Antigen