Hormonal therapy with the goserelin acetate
implant (Zoladex) significantly increases overall survival rates in
patients with locally advanced prostate cancer when administered at
the onset of conventional external irradiation and continued for 3
years. Results of the study, conducted by the European Organization
for Research and Treatment of Cancer (EORTC) Radiotherapy Cooperative
Group, were presented at the annual meeting of the American Society
for Therapeutic Radiology and Oncology (ASTRO) in San Antonio, Texas.
In addition to the increase in overall survival rates, disease-free
survival rates also increased significantly in the patients treated
with goserelin acetate implant plus radiotherapy when compared to the
group given radiotherapy alone.
The results from this study should change the way that
prostate cancer is treated, said Michel Bolla, MD, head of
radiotherapy at the Hôpital Albert Michallon, in France, and
president of the radiotherapy group of the EORTC. The addition
of goserelin acetate implant to standard radiotherapy for locally
advanced prostate cancer significantly improved survival rates of
patients and could save lives. While many clinicians already combine
these two treatment options, these data confirm the value of this
approach as routine.
Study Methods and Results
From 1987 to 1995, 415 patients under the age of 81 years (median
age, 71 years) with locally advanced prostate cancer were randomly
allocated between the two arms of the study. All patients received
standard pelvic radiotherapy at the start of the trial, but half of
the patients also received a monthly, 3.6-mg subcutaneous injection
of the goserelin acetate implant beginning the first day of radiation
that was continued for a period of 3 years. Patients in the combined
treatment group also received 150 mg/d of cyproterone acetate for 1
full month, starting 1 week before the first injection of goserelin.
The addition of the goserelin acetate implant significantly improved
the 5-year overall survival rate from 62% to 78% (P < .001). Over
the 5-year period, clinical disease-free survival was also
significantly increased (from 40% to 75%; P < .001), as was local
control (from 79% to 97%; P < .001). The median follow-up was 61 months.