No difference in the rates of biochemical failure was found between
patients with stage T1 or T2 prostate cancer and a prostate-specific antigen
(PSA) level of up to 10 ng/mL treated with radical prostatectomy and those
treated with radiation therapy, stated Dr. Douglas Keyser of the Department
of Radiation Oncology at the Cleveland Clinic Foundation in Ohio.
This finding is based on a large, single-institution experience with
a relatively homogeneous population of 607 patients, with a median follow-up
of 24 months. A total of 253 patients, with a median age of 70, underwent
radiation therapy, and 354 patients, only 10% of whom were 70 years or
older, underwent prostatectomy. All patients studied had to have pretreatment
PSA levels of up to 10 ng/mL and clinical stage T1 or T2 disease. In addition,
no patients received any type of adjuvant or neoadjuvant therapy.
The outcome based on pretreatment factors such as the stage of disease,
Gleason score, and initial PSA level was analyzed. The clinical stage of
disease had little impact on outcome regardless of the treatment. Patients
with Gleason scores up to 6 fared about the same regardless of treatment;
however, patients with Gleason scores higher than 7 seemed to fare better
with radiation therapy than with surgery.
The pretreatment PSA level is still considered the most potent predictor
of biochemical failure, according to Dr. Keyser. Based on the proceedings
at the San Antonio Consensus Conference in the fall of 1996, a new definition
of biochemical failure has been proposed: three consecutive rising PSA
levels above the nadir value. Patients with PSA levels of up to 4 ng/mL
did quite well regardless of the type of treatment; however, 30% to 40%
of patients with PSA levels of 4 to 10 ng/mL experienced a biochemical
failure. For the entire cohort of patients studied, the biochemical relapse-free
survival was similar for both patients who underwent radiotherapy (75%)
and patients who underwent prostatectomy (76%) at 5 years.