Real world comparison of adjuvant vs. salvage radiation therapy on cancer-control outcomes after radical prostatectomy

TL;DR

This study compares cancer outcomes after adjuvant or salvage radiation therapy following prostatectomy and finds no significant differences in survival rates.

Contribution

The study provides real-world evidence that adjuvant and salvage radiation therapies yield similar mid-term cancer control outcomes.

Findings

Adjuvant radiation therapy patients had worse baseline tumor characteristics but similar 60-month metastasis-free survival rates compared to salvage therapy patients.

No significant differences in cancer-specific or overall survival were observed between adjuvant and salvage radiation therapy groups.

High-risk patient subgroups showed similar outcomes, though adjuvant therapy showed slightly higher overall survival rates.

Abstract

Outcomes of adjuvant (aRT) or salvage radiation therapy (sRT) after radical prostatectomy are under investigation regarding cancer-control outcomes.

Relying on the University Cancer Center database elaborating differences in metastasis-free (MFS), cancer-specific (CSS) and overall survival (OS) of aRT vs. sRT-treated patients between 2014–2024. Sensitivity analyses addressed high-risk patients with pN1 and/or Gleason score 8–10 and/or pT3–4 stage.

Of 1862 patients, 7.1% underwent aRT and 93% were in the sRT group. Median PSA at sRT was 0.33 ng/ml. Patients with aRT harbored significantly worse baseline tumor and pathological characteristics such as PSA level (12.0 vs. 7.6 ng/ml), Gleason score 9–10 (30% vs. 9.8%), D’Amico high risk prostate cancer (97% vs. 56%), as well as pT3–4, pN1 and positive surgical margins rates (all p < 0.001). Similar observations were made for high-risk patients. No differences were observed for aRT vs. sRT with 60-month MFS rates of 85.1% vs. 95.4% (hazard ratio [HR] 0.60, p = 0.18). 60-months CSS-rates of 96.8% vs. 99.1% and 60-month OS-rates of 91.0% vs. 89.1% respectively (all p ≥ 0.15). Neither sensitivity analyses of high-risk patients nor multivariable adjusted Cox regression models revealed significant differences regarding MFS, CSS or OS in aRT vs. SRT comparison (all p ≥ 0.05), despite aRT showing qualitatively better OS results.

Within real-world setting, patients undergoing aRT harbor wore tumor characteristics. However, these differences did not translate into significant differences of mid-term oncological outcomes, relative to sRT patients. Similar observations were made within analyses of high-risk patients with pT3–4 and/or Gleason 8–10 and/or pN1 stage, nevertheless aRT showed slightly higher OS rates within this subgroup.

Figures