Adjuvant androgen deprivation therapy loses its therapeutic benefit after premature termination: an experience of combined modality treatment on prostate cancer.
BACKGROUND
To investigate the effect of the premature termination of recommended androgen deprivation therapy (ADT) as an adjunct to radiotherapy.


METHODS
Between December 2001 and March 2004, 92 patients with non-metastatic prostate cancer underwent primary, curative radiotherapy via an intensity-modulated technique. Four patients (5%) were treated with a dosage of 70.2 Gy, while 74 (80%) and 14 patients (15%) were treated to 72 and 75.6 Gy. Thirty patients (33%) received pelvic irradiation to 45 Gy as a part of their treatment. Seventy-nine patients (86%) also received variable ADT, but only 35 patients (38%) followed a strict protocol when on ADT. Biochemical failure was defined as nadir plus 2 ng/mL or if there was any clinical evidence of tumor recurrence.


RESULTS
The median follow-up time was 37.5 months (20.4-57.8 months). The 3-year overall survival rate was 91.8%. The estimated 3 year recurrence-free survival rates were 100%, 88.9%, and 69.7% for the low, intermediate, and high risk groups, respectively. High risk group patients receiving ADT of an inappropriate length was the only significant risk factor correlated to disease recurrence. The 3-year recurrence-free survival rate was extremely poor (28.6%) in high risk group patients who received adjuvant ADT for less than 2 years. This was significantly worse than patients with the same risk who received long-term ADT (88.1%) or no adjuvant ADT (76.4%, p < 0.001).


CONCLUSIONS
Long-term adjuvant ADT after radiotherapy on high risk prostate cancer has no benefit if the duration is less than 2 years. Premature termination should be avoided.
Department of Radiation Oncology, Chang Gung Memorial Hospital, Taipei, Chang Gung University College of Medicine, Taoyuan, Taiwan.
Kang-Hsing
KH
Fan
Yen-Chao
YC
Chen
Cheng-Keng
CK
Chuang
Min-Li
ML
Hsieh
Ji-Hong
JH
Hong
D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000401:mortality / Q000628:therapy*; D015996:Survival Rate
D000726:Androgen Antagonists; D007987:Gonadotropin-Releasing Hormone