IMPACT OF ADJUVANT RADIOTHERAPY ON BIOCHEMICAL RECURRENCE RATES FOR PN1 PROSTATE CANCER PATIENTS
PD-0412
Abstract
IMPACT OF ADJUVANT RADIOTHERAPY ON BIOCHEMICAL RECURRENCE RATES FOR PN1 PROSTATE CANCER PATIENTS
Authors: Giulia Corrao1, Giulia Marvaso1, Francesco Alessandro Mistretta2, Stefano Luzzago2, Ilaria Sabatini2, Ettore Di Trapani3, Gabriele Cozzi3, Roberto Bianchi2, Matteo Ferro3, Deliu Victor Matei3, Gennaro Musi2, Matteo Pepa4, Mattia Zaffaroni4, Barbara Alicja Jereczek-Fossa1, Ottavio De Cobelli5
1IEO, European Institute of Oncology IRCCS; University of Milan, Division of Radiation Oncology; Department of Oncology and Hematoncology, Milan, Italy; 2IEO, European Institute of Oncology IRCCS, Department of Urology, Milan, Italy; 3IEO, European Institute of Oncology IRCCS, Department of Urology , Milan, Italy; 4IEO, European Institute of Oncology IRCCS, Division of Radiation Oncology, Milan, Italy; 5IEO, European Institute of Oncology IRCCS; University of Milan, Department of Urology; Department of Oncology and Hematoncology, Milan, Italy
Show Affiliations
Hide Affiliations
Purpose or Objective
The optimal management strategy for pN1 prostate
cancer (PCa) patients after primary surgery is still debated. To address these
voids, we compared long term biochemical recurrence rates (BCR) in pN1 patients
that underwent adjuvant radiotherapy (aRT) vs. observation +/- early salvage RT
(esRT) after radical prostatectomy (RP).
Material and Methods
Inclusion criteria were the following: patients
treated between 2010 and 202, pN1 after RP, informed written Consent to
research purpose. Exclusion criteria were: < 10 lymph nodes removed at
surgery, > 10 positive lymph nodes, persistently detectable PSA after RP,
distant metastases at diagnosis. First, Kaplan-Meier plots depicted BCR rates
and univariable and multivariable Cox regression models focused on predictors
of BCR. Second, univariable and multivariable Cox regression models were
refitted after propensity score (PS) matching.
Results
Two hundred and twenty patients met inclusion
criteria, 133 (60%) vs. 87 (40%) patients were treated with aRT vs. noRT/esRT
respectively. Specifically, 26 (12%) patients initially managed with
observation after RP developed BCR and were subsequently treated with esRT.
Median time from RP to esRT was 40 months (IQR: 17-62). The aRT patients were
older (67 vs. 63 yrs, p<0.001). Higher rates of postoperative pathological
ISUP grade group 4-5 pCa were observed in aRT patients (51 vs. 25%;
p<0.001). A statistically significant difference was recorded in aRT and
noRT/esRT regarding pT stage (5 vs. 14 patients in stage pT2; 43 vs. 40 in
stage pT3a and 85 vs. 33 in stage pT3b, p <0.001). Median time to BCR was 62
vs. 38 months in aRT vs. noRT/esRT patients (p=0.001) (Figure 1). In
multivariable Cox regression models, noRT/esRT patients were associated with
higher BCR rates (hazard ratio [HR]: 3.27, p<0.001), relative to aRT group. BCR
were comparable independently of the number of positive lymph nodes (<1 vs
≥2). After PS matching (ratio 1:1; aRT = 57 vs. noRT/ esRT= 57) a 5-year BCR
rate significant difference was observed (respectively, 40.4 (aRT) vs. 76.4%
(noRT/sRT); p<0.01) (Figure 2).
Conclusion
aRT should be considered in treatment of pN1
patients. Specifically, patients managed with observation/esRT experienced BCR
approximately two years before their aRT counterparts. Randomized clinical
trials are needed to define the correct management of this cohort of patients.