PHOENIXA matched-pair analysis suggests that early
postoperative adjuvant radiation therapy significantly re-duces the
risk of biochemical failure in prostate cancer patients with capsular
penetration after prostatectomy.
The Thomas Jefferson University researchers identified 149 patients
at the Kimmel Cancer Center who had capsular penetration and absence
of nodal metastasis after prostatectomy. None of these patients
had elevated postoperative PSA within 6 months of the time of radical
prostatectomy. They received no prior hormonal therapy or
chemotherapy, Richard K. Valicenti, MD, said at the annual
meeting of the American Society of Therapeutic Radiology and Oncology (ASTRO).
From this group, the researchers matched 36 patients who received
adjuvant radiation therapy and 36 patients who did not receive
adjuvant therapy for preoperative PSA, Gleason score, surgical margin
status, and seminal vesicle invasion. These are prognostic
factors highly predictive of biochemical failure and outcome,
Dr. Valicenti said.
With a median follow-up of 41 months (minimum, 2 years), the study
showed 17 biochemical failures among the patients who did not receive
adjuvant radiation therapy, compared with only four such failures in
the adjuvant therapy group.
There was 93% biochemical control in the patients who received
adjuvant irradiation vs 66% in patients who were observed, Dr.
Valicenti said. This represents an 83% reduction in biochemical
failure among patients who had adjuvant treatment.
He added that the study has shown no difference in clinical outcomes
(local control, disease-specific survival, or overall survival).
I think the lack of a survival difference is due more to the
absence of clinical events rather than their presence, he said.