Prostate-specific antigen bounce in patients treated before 60 years old by iodine 125 brachytherapy for prostate cancer is frequent and not a prognostic factor

Brachytherapy for favorable prognostic prostate cancer in men up to 60 years of age: Long term follow-up

PURPOSE

Brachytherapy (BT) is a standard treatment for low- and favorable intermediate-risk prostate adenocarcinoma. Few studies have focused on young patients. We therefore evaluated long-term efficacy and toxicity of BT in patients aged ≤ 60 years with low- and favorable intermediate-risk prostate cancer.

MATERIALS AND METHODS

This retrospective study included patients aged ≤60 years with low- or favorable intermediate-risk prostate adenocarcinoma treated with iodine BT alone between 1999 and 2014 at the Institut de Cancérologie de Lorraine. Follow-up assessment included incidence of biochemical failure (BF) at 10 and 15 years after BT, as well as survival data and late toxicities.

RESULTS

A total of 177 patients of median age 56 years (54-58) were analyzed, with a median follow-up of 126 months (97-172). Incidence of BF at 10 and 15 years after BT was 5.4% and 11.7% respectively. PSA nadir (HR = 51.8 [95% CI 6.69-277], p < 0.001), age at treatment (HR = 1.78 [95% CI 1.19-2.65], p = 0.005) and prostate D90% (HR = 1.08 [95% CI 1.01-1.15], p < 0.021) were identified as predictive factors of BF. Overall survival at 10 and 15 years after BT was 92.8% and 84.4% respectively. Cancer-specific survival at 10 and 15 years after BT was 99.3% and 97.7% respectively. No major toxicity was recorded.

CONCLUSIONS

Exclusive BT is a long-term effective treatment for patients aged ≤ 60 years with low- or favorable intermediate-risk prostate adenocarcinoma.

Prostate-Specific Antigen Bounce after 125I Brachytherapy Using Stranded Seeds with Intraoperative Optimization for Prostate Cancer

Prostate-specific antigen (PSA) bounce is common in patients undergoing 125I brachytherapy (BT), and our study investigated its clinical features. A total of 100 patients who underwent BT were analyzed. PSA bounce and large bounce were defined as an increase of ≥0.2 and ≥2.0 ng/mL above the initial PSA nadir, respectively, with a subsequent decline without treatment. Biochemical failure was defined using the Phoenix definition (nadir +2 ng/mL), except for a large bounce. With a median follow-up of 49 months, 45% and 7% of the patients experienced bounce and large bounce, respectively. The median time to bounce was 24 months, and the median PSA value at the bounce spike was 1.62 ng/mL, a median raise of 0.44 ng/mL compared to the pre-bounce nadir. The median time to bounce recovery was 4 months. The post-bounce nadir was obtained at a median of 36 months after low-dose-rate BT. On univariate analysis, age, the PSA nadir value at 2 years, and prostate volume were significant factors for PSA bounce. The PSA nadir value at 2 years remained significant in multivariate analysis. We should carefully monitor young patients with high prostate volume having a >0.5 PSA nadir value at 2 years for PSA bounce.

Prognostic value of PSA bounce after definitive radiotherapy revisited

BACKGROUND

Prostate-specific antigen (PSA) bounce after definitive radiotherapy has been reported as a predictor of improved biochemical recurrence-free survival (BCRFS). We revisited this phenomenon to confirm its clinical impact on oncological outcomes in patients with long-term follow-up who were free of biochemical recurrence (BCR) at least 3 years after treatment.

MATERIALS AND METHODS

A total of 541 patients with localized, intermediate-risk prostate cancer underwent low-dose rate brachytherapy with iodine-125 seeds with or without supplemental external beam radiotherapy in combination. Neoadjuvant hormonal therapy was administered to 273 patients (50.5%) with a median duration of 3 months (range 1-108 months). PSA bounce was defined as ≥ 0.2 ng/ml increase above the interval PSA nadir, followed by a decrease below that value.

RESULTS

The median age was 69 years (range 49-90 years). The median follow-up duration was 102 months (range 36-205 months). One-hundred and fifty patients (27.7%) had PSA bounce with a median magnitude of 0.47 ng/ml (range 0.2-3.19 ng/ml). Age was significantly associated with the occurrence of PSA bounce [age: hazard ratio (HR) 0.95, 95% confidence interval (CI) 0.93-0.98]. It was found to be independently associated with a decreased risk for BCR (HR 0.29; 95% CI 0.12-0.69) and clinical progression (HR 0.44; 95% CI 0.95-0.98).

CONCLUSION

PSA bounce indicated a favorable BCRFS and clinical progression-free survival in patients who had been free of BCR for at least 3 years after definitive radiotherapy.

Prognostic value of PSA bounce in prostate cancer following definitive radiation therapy: a systematic review and meta-analysis

BACKGROUND

The prognostic significance of PSA bounce following definitive radiation therapy remains controversial. To develop a sense of current opinion in this area, we performed a systematic search of the literature based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

METHODS

In January 2021, we systematically searched PubMed, the Cochrane library, and Scopus for studies that compared patients who had localized prostate cancer with or without PSA bounce after definitive radiation therapy. Our objective was to evaluate the association of PSA bounce with biochemical recurrence-free survival, metastatic-free survival, cancer-specific survival, and overall survival, using multivariate Cox regression analysis.

RESULTS

A total of 8881 patients in 10 studies matched the selection criteria for the systematic review and meta-analysis. The number of patients with PSA bounce accounted for 2706 of all 8881 patients (30.5%). PSA bounce was associated with better biochemical recurrence-free survival after definitive radiation therapy (pooled HR: 0.62, 95% CI: 0.54-0.71). Subgroup analyses also showed that PSA bounce was independently associated with decreased risk for biochemical recurrence-free survival in prostate cancer patients treated with low dose rate brachytherapy alone (pooled HR: 0.38, 95% CI: 0.27-0.55) and external beam radiotherapy alone (pooled HR: 0.71, 95% CI: 0.57-0.87).

CONCLUSIONS

This meta-analysis indicated that PSA bounce after definitive radiation therapy is related to improved outcome in terms of biochemical failure in prostate cancer patients.

Racial differences in the PSA bounce in predicting prostate cancer outcomes after brachytherapy: Evidence from the Department of Veterans Affairs

PURPOSE

African American men have historically had poorer prostate cancer biochemical and survival outcomes than Caucasians. However, emerging data suggest nononcologic factors drive much of this disparity. Prior evidence has suggested an association between a transient prostate specific antigen (PSA) bounce and improved biochemical control. However, racial differences in this relationship have remained relatively unexplored.

METHODS AND MATERIALS

We identified 4477 men treated for low- or intermediate-risk prostate cancer within the U.S. Department of Veterans Affairs (VA) from 2000 to 2010 with brachytherapy alone or in combination with external beam radiotherapy without androgen deprivation. Longitudinal PSA data were used to define to biochemical failure and PSA bounce. Cox proportional hazard models were used explore racial differences in the relationship between the PSA bounce and time to biochemical failure.

RESULTS

Thirty-one percent of our sample experienced a PSA bounce, with African Americans more likely to experience a bounce (42%) compared with Caucasians (29%); p < 0.001. Despite this, African Americans had a higher likelihood of biochemical failure (hazard ratio [HR] 1.4; p = 0.006). However, African American men experiencing a PSA bounce were less likely to experience a biochemical failure (HR = 0.64; p = 0.046), whereas this relationship was not statistically significant for Caucasians (HR = 0.78; p = 0.092). On multivariate analysis, African Americans receiving brachytherapy alone were most sensitive to the protective benefit of the PSA bounce (HR = 0.64).

CONCLUSIONS

A PSA bounce was associated with improved biochemical control among patients receiving brachytherapy as part of their treatment for low- or intermediate-risk prostate cancer at the VA. African American men treated with brachytherapy had a particularly pronounced biochemical control benefit of a PSA bounce.

Multi-Institutional Analysis of Prostate-Specific Antigen Kinetics After Stereotactic Body Radiation Therapy

PURPOSE

Understanding prostate-specific antigen (PSA) kinetics after radiation therapy plays a large role in the management of patients with prostate cancer (PCa). This is particularly true in establishing expectations regarding PSA nadir (nPSA) and PSA bounces, which can be disconcerting. As increasingly more patients are being treated with stereotactic body radiation therapy (SBRT) for low- and intermediate-risk PCa, it is imperative to understand the PSA response to SBRT.

METHODS AND MATERIALS

PSA data from 5 institutions were retrospectively analyzed for patients with localized PCa treated definitively with SBRT alone from 2004 to 2016. Patients received 35 to 40 Gy in 5 fractions, per institutional standards. Patients who had less than 12 months of PSA data or received androgen deprivation therapy were excluded from this study. Linear and logistic multivariable analysis were performed to identify predictors of nPSA, bounce, and biochemical recurrence, and joint latent class models were developed to identify significant predictors of time to biochemical failure.

RESULTS

A total of 1062 patients were included in this study. Median follow-up was 66 months (interquartile range [IQR], 36.4-89.9 months). Biochemical failure per the Phoenix criteria occurred in 4% of patients. Median nPSA was 0.2 ng/mL, median time to nPSA was 40 months, 84% of patients had an nPSA ≤0.5 ng/mL, and 54% of patients had an nPSA ≤0.2 ng/mL. On multivariable analysis, nPSA was a significant predictor of biochemical failure. Benign PSA bounce was noted in 26% of patients. The median magnitude of PSA bounce was 0.52 ng/mL (IQR, 0.3-1.0 ng/mL). Median time to PSA bounce was 18.1 months (IQR, 12.0-31.1 months). On multivariable analysis, age and radiation dose were significantly associated with a lower incidence of bounce. Joint latent class models modeling found that nPSA and radiation dose were significantly associated with longer time to biochemical failure.

CONCLUSIONS

In this multi-institutional cohort of patients with long-term follow-up, we found that SBRT led to low nPSAs. In turn, lower nPSAs are associated with reduced incidence of, and longer time to, biochemical failure. Benign PSA bounces occurred in a quarter of patients, as late as several years after treatment. Further studies are needed to directly compare the PSA response of patients who receive SBRT versus other treatment modalities.