Salvage radiotherapy in prostate cancer patients with biochemical relapse after radical prostatectomy : Prolongation of prostate-specific antigen doubling time in patients with subsequent biochemical progression

Salvage Radiotherapy for Relapsed Prostate Cancer after Radical Prostatectomy Is Associated with Normal Life Expectancy

In patients with prostate cancer (PCa), salvage radiotherapy (SRT) for biochemical progression (BP) after radical prostatectomy (RP) improves PCa-specific survival. However, no prospective randomized trials have compared the effect of SRT with untreated patients. In this analysis of 151 patients who received SRT for post-RP BP, we compared their overall survival (OS) with virtual, age-matched controls (n = 151,000) retrieved from government life tables. We also investigated the risk factors associated with BP and OS and compared the prostate-specific antigen (PSA) doubling times (DTs) before and after SRT for patients with BP. The median follow-up was 9.3 years for BP and 17.4 years for OS. The risk factors significantly affecting BP were Gleason score (p < 0.001), pre-SRT PSA (p = 0.003), and negative surgical margins (p = 0.003). None of these risk factors were associated with OS. In 93 patients with BP after SRT, the median PSADT was significantly prolonged compared with pre-SRT values (3.7 vs. 8.3 months, p < 0.001). The OS did not differ between patients and controls (p = 0.112), and life expectancy was similar, likely due to the survival benefit of SRT. The prolonged PSADT after SRT further supports the beneficial role of SRT in this patient population. However, subsequent treatments were not systematically recorded, which may have affected the results.

Study of prostate-specific antigen levels during salvage radiotherapy after prostate cancer surgery

BACKGROUND

Administration of adjuvant or salvage radiotherapy (RT) after prostate cancer (PCa) surgery is supported by clinical evidence and is a widely adopted strategy. On occasion, we detect changes in prostate-specific antigen (PSA) levels, such as a transient elevation or decline, during RT. Thus, we retrospectively investigated the frequency of changes in PSA levels, their associations with histopathological parameters, PSA doubling time (PSADT), and biochemical recurrence (BR) of PCa.

METHODS

This study included 23 consecutive patients who underwent surgery for PCa between 2012 and 2019, received salvage RT without hormone therapy, and exhibited changes in PSA levels during RT. The prostatic bed was irradiated with a total dose of 64 to 66 Gy. BR was defined as consecutive PSA levels exceeding 0.2 ng/mL or having to start hormone therapy because of PSA elevation after salvage RT.

RESULTS

During salvage RT after PCa surgery, PSA levels transiently increased in 11 patients (47.8%) and decreased in 12 (52.2%). When factors associated with BR were examined in patients with transient PSA elevation, seminal vesicle invasion and preoperative PSA values were identified as being statistically significant. When factors for BR were examined in patients with a decline in PSA levels, the Gleason score and PSADT were identified as being significant. Among the cases of a decline in PSA levels during salvage RT, those who received a radiation dose of less than 36 Gy did not experience BR. Similarly, patients who exhibited changes in PSA levels during salvage RT and did not have perineural invasion did not experience BR.

CONCLUSION

This is the first study to examine the histopathological factors possibly affecting BR in patients undergoing salvage RT after PCa surgery. The results indicate that in patients with transient PSA elevation, seminal vesicle invasion is a significant risk factor. On the other hand, in patients with a decline in PSA levels during irradiation, the Gleason score and perineural invasion were found to be potential risk factors for BR. These findings suggest that a thorough examination of postoperative histopathological results may be necessary for the optimal management of patients with PCa.

Utility of a Fifth-Generation Ultrasensitive Prostate-Specific Antigen Assay for Monitoring Prostate Cancer Patients after Radical Prostatectomy with 3 Years of Follow-Up

BACKGROUND

We investigated an ultrasensitive prostate-specific antigen (uPSA) immunoassay (MesoScale; lower limit of detection (LLD) of 0.0035 pg/mL) to monitor patients with prostate cancer (PCa) following radical prostatectomy (RP) and to examine whether changes in PSA in the conventionally undetectable range (<1 pg/mL) can predict biochemical relapse (BCR).

METHODS

We measured uPSA in serial serum samples (N = 100) collected from 20 RP cases with a third-generation ELISA (LLD of 1 pg/mL) and the fifth-generation MesoScale assay. We analyzed the PSA nadir changes to classify patients into BCR or non-BCR groups, observed the trends in PSA kinetics, and associated BCR status with clinicohistopathological features.

RESULTS

The ELISA could quantify PSA in only 38% of the RP samples, detecting BCR in 7 of 20 patients with PCa. The MesoScale assay quantified PSA in all samples, showing 8 of 20 patients with BCR. However, there was no significant difference between the median time to BCR detection based on ELISA (1016 days) compared with MesoScale data (949 days). Gleason scores were higher in the BCR groups compared with non-BCR. There was no significant difference for other clinicohistopathological parameters.

CONCLUSIONS

The uPSA MesoScale technology could track miniscule changes in serum PSA in the range of 0.003-1 pg/mL in all RP cases. However, PSA kinetics and nadir at concentrations <2 pg/mL fluctuated, and increases below this range could not reliably suggest signs of BCR. Instead, ultrasensitive fifth-generation PSA assays may hold clinical potential for measuring the low concentrations of PSA in women for various medical contexts.

Comparison of relative and absolute rectal dose-volume parameters and clinical correlation with acute and late radiation proctitis in prostate cancer patients

PURPOSE

To compare relative and absolute dose-volume parameters (DV) of the rectum and their clinical correlation with acute and late radiation proctitis (RP) after radiotherapy (RT) for prostate cancer (PCa).

PATIENTS AND METHODS

366 patients received RT for PCa. In total, 49.2% received definitive RT, 20.2% received postoperative RT and 30.6% received salvage RT for biochemical recurrence. In 77.9% of patients, RT was delivered to the prostate or prostate bed, and additional whole pelvic RT was performed in 22.1%. 33.9% received 3D-RT, and 66.1% received IMRT. The median follow-up was 59.5 months (18.0-84.0 months). The relative (in %) and absolute (in ccm) rectal doses from 20-75 Gy including the receiver operating characteristics curves (rAUC) from 30-65 Gy (in % and ccm) and several other clinical parameters were analyzed in univariate and multivariate analyses. We performed the statistical analyses separately for the entire cohort (n = 366), patients with (n = 81) and without (n = 285) pelvic RT, comparing RP vs. RP ≥ grade I.

RESULTS

With the exception of the V50_Gyccm (p = 0.02) in the univariate analyses for acute RP in the entire patient cohort, no absolute DV parameter (in ccm) was statistically significant associated with either acute or late RP. In the multivariate analyses, 3D-RT (p < 0.008) and rAUC_V30-50 Gy% (p = 0.006) were significant parameters for acute RP for the entire cohort, and the V50_Gy% (p = 0.01) was the significant parameter for patients with pelvic RT. The rAUC_V40-50 Gy% (p = 0.004) was significant for RT to the prostate/prostate bed. Regarding the statistical analysis for late RP, the rAUC_V30-65 Gy% (p = 0.001) was significant for the entire cohort, and rAUC_V30-50 Gy% (p = 0.001) was significant for RT of the prostate/prostate bed. No parameter was significant in patients with pelvic RT.

CONCLUSION

Absolute DV parameters in ccm are not required for RT in PCa patients.