CHICAGOAlthough radiotherapy has been administered after prostatectomy for decades to improve disease-free survival in men who have
pathologic risk factors, its use in high-risk men who have undetectable PSA
levels after prostatectomy is controversial.
Based on results of their study of adjuvant radiotherapy in men with
positive surgical margins but PSA levels below 0.3 ng/mL, investigators from
Baylor College of Medicine, Houston, believe that irradiation of the prostatic
bed and periprostatic tissue should be considered after prostatectomy even if
the PSA is not elevated.
The median disease-free interval for men receiving adjuvant radiotherapy was
more than two times longer than it was for men who were observed after surgery.
"Adjuvant radiotherapy can provide excellent long-term BNED [biochemical
no evidence of disease] for men with positive surgical margins," said
Michael D. Bastasch, MD, resident in radiation oncology in the Department of
Radiology. He reported the results at the 87th Scientific Assembly and Annual
Meeting of the Radiological Society of North America (abstract 34).
The researchers reviewed outcomes in 44 men who had been referred to their
institution for treatment for prostate cancer between 1989 and 1995. All had
undetectable PSA levels after surgery, negative lymph nodes, and no prior
hormone therapy. All received adjuvant radiotherapy because of positive
pathologic findings at the surgical margins.
Patients received radiotherapy over a period of 1.5 to 11 months after
prostatectomy. Radiotherapy was delivered to the prostatic bed and surrounding
prostatic tissues at a total median dose of 60 Gy (range, 59.4 to 66 Gy) given
in fractions of 1.8 to 2.0 Gy.
Biochemical no evidence of disease (bNED) results in this group of patients
were compared with findings from an observational group of 189 men from the
same time period from the Specialized Program for Research Excellence (SPORE)
database who had positive surgical margins and undetectable PSA levels after
prostatectomy. Both groups were similar in terms of age, preoperative PSA,
Gleason score, extracapsular extension, and seminal vesicle involvement.
The primary endpoint of the study was detection of PSA. The entire group was
followed for a median of 60.4 months after surgery; the median follow-up in the
adjuvant radiotherapy group was 89.8 months, and in the observational group, 59