(UroToday.com) The 2023 European Association of Urology (EAU) annual congress held in Milan, Italy between March 10th and 13th, 2023 was host to an abstract session of studies addressing long-term prostate cancer control outcomes. Dr. Francesco Chierigo presented the results of a multi-centric study evaluating survival after radical prostatectomy versus radiation therapy in clinically node-positive prostate cancer patients.
The aim of this study was to compare the biochemical recurrence-free, metastasis-free, and overall survival rates among clinically node positive (cN1) prostate cancer patients undergoing a radical prostatectomy versus external beam radiotherapy. Using a multi-institutional database from 16 academic centers, the investigators identified 402 consecutive patients with cN1 disease, defined via RECIST1.1 or PROMISE criteria. Among these 402 patients, the primary treatment modality was external beam radiotherapy and a radical prostatectomy in 66 (16%) and 336 (84%) patients, respectively. The binary outcome of PSA persistence after primary treatment was statistically evaluated using logistic regression analysis. Conversely, the time-to-event outcomes of biochemical recurrence-free, metastasis-free, and overall survival rates were evaluated using Kaplan-Meier plots (univariable) and Cox regression models (multivariable), adjusting for patient age, D’Amico risk group, subsequent treatment with adjuvant or salvage radiotherapy, and administration of androgen deprivation therapy.
Baseline patient characteristics are demonstrated below. It is important to note that there were important differences in baseline characteristics between the RP and EBRT patient cohorts that suggest a selection bias in treatment choice for these patients. Patients in the EBRT group were older (73 versus 67 years, p<0.001), had a higher baseline serum PSA level (16 versus 10 ng/ml, p<0.001), and were more likely to have D’Amico high risk disease (88% versus 69, p=0.004). As expected, patients in the EBRT group received ADT more frequently (79% versus 38%), whereas those in the RP group received adjuvant/salvage radiotherapy more commonly (44% versus 1.5%).
On logistic regression analysis, there was no statistically significant difference between the two treatment groups with regards to the outcome of PSA persistence. In the Kaplan Meier curves below (univariable analysis), it appeared that the biochemical recurrence-free (86% EBRT versus 76% RP, p=0.15) and metastasis-free (97% versus 83%, p=0.051) survival rates were non-significantly better in the EBRT arm. Conversely, overall survival rates (97% versus 87%, p<0.001) were significantly better in the RP arm, likely a reflection of a selection bias for better overall comorbidity/performance status in the RP cohort at time of intervention.
These findings on univariable results were consistent on multivariable cox regression modeling. RP was associated with a significant improvement in overall survival (HR: 0.12, 95% CI: 0.02 to 0.72, p=0.02), again likely secondary to an underlying selection bias.
Based on these results, the authors concluded that RP and EBRT have similar early oncologic outcomes, but RP may be associated with an overall survival advantage for the treatment of cN1 prostate cancer, even after adjustment for age, adverse clinical features, and subsequent adjuvant/salvage treatment, but not baseline performance status and comorbidity scores.
Presented by: Dr. Francesco Chierigo, MD, Department of Urology, IRCCS Policlinico San Martino Hospital, University of Genova, Genoa, Italy
Written by: Rashid K. Sayyid, MD, MSc – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2023 European Association of Urology (EAU) Annual Meeting, Milan, IT, Fri, Mar 10 – Mon, Mar 13, 2023.