Radiation Therapy vs Surgery for Early-Stage Prostate Cancer: Similar Rates of Biochemical Failure

No difference in the rates of biochemical failure was found betweenpatients 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 thosetreated with radiation therapy, stated Dr. Douglas Keyser of the Departmentof Radiation Oncology at the Cleveland Clinic Foundation in Ohio.

This finding is based on a large, single-institution experience witha relatively homogeneous population of 607 patients, with a median follow-upof 24 months. A total of 253 patients, with a median age of 70, underwentradiation therapy, and 354 patients, only 10% of whom were 70 years orolder, underwent prostatectomy. All patients studied had to have pretreatmentPSA 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 ofdisease had little impact on outcome regardless of the treatment. Patientswith Gleason scores up to 6 fared about the same regardless of treatment;however, patients with Gleason scores higher than 7 seemed to fare betterwith radiation therapy than with surgery.

The pretreatment PSA level is still considered the most potent predictorof biochemical failure, according to Dr. Keyser. Based on the proceedingsat the San Antonio Consensus Conference in the fall of 1996, a new definitionof biochemical failure has been proposed: three consecutive rising PSAlevels above the nadir value. Patients with PSA levels of up to 4 ng/mLdid 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 biochemicalfailure. For the entire cohort of patients studied, the biochemical relapse-freesurvival was similar for both patients who underwent radiotherapy (75%)and patients who underwent prostatectomy (76%) at 5 years.