Source: DGNews  |  Posted 2 years ago

By Chris Berrie

BARCELONA, Spain -- December 1, 2009 -- Adjuvant radiotherapy (ART) provides
significant improvements in biochemical outcome over salvage radiotherapy (SRT)
in patients with prostate cancer with a high risk of disease recurrence
(pT3-4N0), according to a matched-control analysis presented here on November
28 at the 2nd European Multidisciplinary Meeting on Urological Cancers (EMUC).

As principal investigator Gert De Meerleer, MD, PhD, Ghent University Hospital,
Ghent, Belgium, noted initially, “All patients have been treated with
intensity-modulated radiotherapy, which has enabled us to give much higher
doses than traditionally given in adjuvant postoperative or salvage
postoperative settings.”

Thus, the aim was to determine the appropriate timing of this postoperative
intensity-modulated radiotherapy after radical prostatectomy for patients with
high risk of disease recurrence.

The full patient population included 298 patients: 133 treated with ART (74 Gy)
and 165 with SRT (76 Gy). Patients were matched in a 1:1 ratio according to
preoperative prostate-specific antigen (PSA) levels (<10 or >=10 ng/mL),
Gleason score (<4+3 or >=4+3), and pathological T stage (pT) of pT3a, pT3b, or
pT4, without or with 6-month androgen deprivation. The matching criteria of
only pT3-4N0 patients allowed inclusion of 198 of these; all matching was
blinded to patient outcome.

For this analysis, 112 patients were matched. The median follow-up was 34
months from radiotherapy completion for the whole group. Baseline
characteristics across the ART and SRT treatment groups did not differ
significantly for median age, median follow-up, PSA at referral, Gleason score,
tumour stage, androgen deprivation, and perineural invasion. However,
significant differences were seen for positive margins (ART, 72% vs SRT, 52%;
P < .05) and PSA <1 ng/mL at start of radiotherapy (ART, 98% vs SRT,
62%; P < .05).

The investigators found a significant reduction in 3-year biochemical failure
for ART, compared with SRT: 91% versus 59% (P = .004). There was no
significant difference in biochemical relapse-free survival (RFS) for ART and
SRT when pre-radiotherapy PSA levels were <1 ng/mL (91% vs 75%), suggesting SRT
may be effective in this scenario.

PSA >10 ng/mL at diagnosis, PSA >1 ng/mL before start of radiotherapy, and
negative surgical margins predicted a reduced biochemical RFS in the SRT group.

On multivariate analysis, ART, Gleason score <4+3, and preoperative PSA <10
ng/mL were significantly correlated with better biochemical RFS.

Thus, while noting that “within the urology community there is still some
reluctance to send patients immediately after surgery for adjuvant
radiotherapy, and [physicians] wait until the PSA goes up,” Professor Meerleer
stressed that waiting and performing SRT later leads to significantly worse
results for the patient compared with implementing immediate ART.

EMUC was co-organised by the European Association of Urology (EAU), the
European Society for Medical Oncology (ESMO), and the European Society for
Therapeutic Radiology and Oncology (ESTRO).

Presentation title: A Matched-Control Analysis of Adjuvant and Salvage
Postoperative Intensity-Modulated Radiotherapy for pT3-4N0 Prostate Cancer.
Abstract P035