Risk Factors for Disease Progression After Postprostatectomy Salvage Radiation: Long-term Results of a Single-institution Experience

Salvage Radiotherapy for Prostate Cancer

For patients experiencing biochemical recurrence in the absence of distant metastasis, salvage radiotherapy (SRT) with or without androgen deprivation therapy (ADT) is currently the only possible curative treatment option. Prostate-specific antigen (PSA) monitoring and the selected use of SRT has some advantages when compared with adjuvant radiotherapy. The most important one is avoidance of a potential overtreatment of patients who would never have disease progression, even in the presence of high-risk pathological features. The identification of a specific PSA cut-off seems to be incorrect. In patients with more adverse pathological features, early SRT administered at the very first sign of a PSA rise granted better disease control. Dose-intensified SRT is feasible and well tolerated with no significant difference in grade 2 or more acute and late toxicity. At least 66 Gy must be given in the salvage setting. ADT has a radio-sensitising effect on the radiotherapy by inhibiting the repair of DNA double-strand breaks. The use of ADT in the salvage setting results in a better oncological outcome. Hormonal therapy is associated with a decrease in quality of life and side-effects depending on the duration of hormone therapy. The oncological benefit of hormone therapy duration depends on their clinical and pathological characteristics. 68-Ga-prostate-specific membrane antigen positron emission tomography-computed tomography is the gold standard in staging prostate cancer patients with biochemical persistence or recurrence after radical prostatectomy. The implementation of 18F-labelled PSMA tracers can provide a further improvement.

Long- versus short-term androgen deprivation therapy with high-dose radiotherapy for biochemical failure after radical prostatectomy: a randomized controlled trial

Radical prostatectomy is a well-established treatment option in the management of localized and locally advanced prostate cancer. An extended lymphadenectomy is performed in case of substantial risk for lymph node involvement. When biochemical recurrence (BCR) occurs, salvage radiotherapy (SRT) is performed. The benefit in terms of BCR-free survival (FS) and metastasis-FS by adding 6 months of androgen deprivation therapy (ADT) compared with SRT only has already been established. Retrospective evidence suggests that a longer schedule of ADT may be more beneficial compared with 6 months. This multicenter open-label randomized trial will include patients who need SRT after experiencing BCR post-radical prostatectomy with lymphadenectomy and pN0-status. Patients will be randomized for ADT duration (6 vs 24 months). Primary end point is distant metastasis-FS.

Clinical Trial Registration: NCT04242017 ( ClinicalTrials.gov )

Prognostic risk classification for biochemical relapse-free survival in patients with oligorecurrent prostate cancer after [68Ga]PSMA-PET-guided metastasis-directed therapy

PURPOSE

Since the success of prostate-specific membrane antigen-positron emission tomography (PSMA-PET) imaging for patients with oligorecurrent prostate cancer (ORPC), it is increasingly used for radiotherapy as metastasis-directed therapy (MDT). Therefore, we developed a prognostic risk classification for biochemical relapse-free survival (bRFS) for patients after PSMA-PET-guided MDT after radical prostatectomy.

METHODS

We analyzed 292 patients with local recurrence (LR) and/or pelvic lymph node (LN) lesions and/or up to five distant LN, bone (BM), or visceral metastases (VM) detected with [⁶⁸Ga]PSMA-PET imaging. Median follow-up was 16 months (range 0-57). The primary endpoint was bRFS after MDT. Cox regression analysis for risk factors was incorporated into a recursive partitioning analysis (RPA) with classification and regression tree method.

RESULTS

PSA at recurrence ≥ 0.8 ng/mL, BM, and VM was significantly associated with biochemical relapse. RPA showed five groups with tenfold cross-validation of 0.294 (SE 0.032). After building risk classes I to IV (p < 0.0001), mean bRFS was 36.3 months (95% CI 32.4-40.1) in class I (PSA < 0.8 ng/mL, no BM) and 25.8 months (95% CI 22.5-29.1) in class II (PSA ≥ 0.8 ng/mL, no BM, no VM). LR and/or pelvic LNs caused relapse in classes I and II. Mean bRFS was 16.0 months (95% CI 12.4-19.6) in class III (PSA irrelevant, present BM) and 5.7 months (95% CI 2.7-8.7) in class IV (PSA ≥ 0.8 ng/mL, no BM, present VM).

CONCLUSION

We developed and internally validated a risk classification for bRFS after PSMA-PET-guided MDT. Patients with PSA < 0.8 ng/mL and local relapse only (LR and/or pelvic LNs) had the most promising bRFS. PSA ≥ 0.8 ng/mL and local relapse only (LR and/or pelvic LNs) indicated intermediate risk for failure. Patients with BM were at higher risk regardless of the PSA. However, those patients still show satisfactory bRFS. In patients with VM, bRFS is heavily decreased. MDT in such cases should be discussed individually.

Superior metastasis-free survival for patients with high-risk prostate cancer treated with definitive radiation therapy compared to radical prostatectomy: A propensity score-matched analysis

Purpose

For high-risk prostate cancer (HR-PCa) in men with a life expectancy of at least 10 years, the National Comprehensive Cancer Network recommends radiation therapy (RT) plus androgen deprivation therapy (ADT) with category 1 evidence or radical prostatectomy (RP) as an acceptable initial therapy. Randomized evidence regarding which therapy is optimal for disease control is lacking for men with HR-PCa. We performed a propensity-score-matched comparison of outcomes for men with localized HR-PCa treated with primary RT or RP.

Methods and materials

The medical records of patients with localized HR-PCa who were treated at our institution between 2002 and 2011 were reviewed. Patient and disease characteristics, treatment details, and outcomes were collected. A combination of nearest-neighbor propensity score matching on age, Adult Comorbidity Evaluation-27 comorbidity index, prostate-specific antigen, biopsy Gleason scores, and clinical T-stage as well as exact matching on prostate-specific antigen, biopsy Gleason scores, and clinical T-stage was performed. Outcomes were measured from diagnosis. Multivariate Cox proportional hazards regression was used to compare metastasis-free and overall survival.

Results

A total of 246 patients were identified with 62 propensity-score-matched pairs. ADT was administered to 6.5% and 80.6% of patients receiving RP and RT, respectively. Five-year rates of metastasis for RP and RT were 33% and 8.9%, respectively (P = .003). Overall survival was not different. Delay of salvage therapy was longer for patients undergoing primary RT (P < .001). Findings were similar when only those patients who did not receive ADT were compared.

Conclusions

At our institution, treatment with primary RT resulted in superior metastasis-free survival over RP. This was not accompanied by an improvement in OS.