Comparison of AUA and phoenix definitions of biochemical failure following permanent brachytherapy for prostate cancer

PURPOSE

To compare biochemical recurrence free survival (BCRFS) and cancer-specific survival (CSS) after brachytherapy using the AUA and the Phoenix definitions.

METHODS AND MATERIALS

2634 men with T1-T4N0M0 prostate cancer were treated with brachytherapy with or without neoadjuvant hormonal therapy or external beam radiation therapy. Five, 10, and 15- year BCRFS and CSS were estimated with Kaplan-Meier estimates with log rank. Multivariate analysis of survival was performed with Cox regression analysis.

RESULTS

Median age was 66, follow-up was 8.6 years, and prostate specific antigen was 6.9. Overall, 11.1% (n = 293) of patients experienced Phoenix BCR and 17.48% (n = 457) experienced AUA BCR. The rates of AUA BCR and Phoenix BCR were significantly different at 5 and 10-years but not at 15 years. Patients treated with BED ≤ 200 Gy were more likely to experience AUA BCR (22.5% vs. 12.4%, OR 1.44, p < 0.001) and Phoenix BCR (14.3% and 8.3%, OR 1.37, p < 0.001) than patients treated with a BED > 200 Gy.

CONCLUSIONS

Compared to the Phoenix definition, the AUA definition of BCR after brachytherapy is associated with significantly worse BCRFS for the first 15 years after treatment. Receiving a BED > 200, which cannot be achieved without the addition of brachytherapy, is associated with better BCRFS and CSS. Our findings reaffirm the importance of dose in the management of prostate cancer.

I-125 or Pd-103 for brachytherapy boost in men with high-risk prostate cancer: A comparison of survival and morbidity outcomes

PURPOSE

Brachytherapy boost improves biochemical recurrence rates in men with high-risk prostate cancer (HRPC). Few data are available on whether one isotope is superior to another. We compared the oncologic and morbidity outcomes of I-125 and Pd-103 in men with HRPC receiving brachytherapy.

METHODS AND MATERIALS

Of 797 patients with HRPC, 190 (23.8%) received I-125 or 607 received Pd-103 with a median of 45 Gy of external beam irradiation. Freedom from biochemical failure (FFBF), freedom from metastases (FFMs), cause-specific survival (CSS), and morbidity were compared for the two isotopes by the ANOVA and the χ² test with survival determined by the Kaplan-Meier method and Cox regression.

RESULTS

Men treated with I-125 had a higher stage (p < 0.001), biological equivalent dose (BED) (p < 0.001), and longer hormone therapy (neoadjuvant hormone therapy, p < 0.001), where men treated with Pd-103 had a higher Gleason score (GS, p < 0.001) and longer followup (median 8.3 vs. 5.3 years, p < 0.001). Ten-year FFBF, FFM, and CSS for I-125 vs. Pd-103 were 77.5 vs. 80.2% (p = 0.897), 94.7 vs. 91.9% (p = 0.017), and 95.4 vs. 91.8% (p = 0.346), respectively. Men with T3 had superior CSS (94.1 vs. 79.5%, p = 0.001) with I-125. Significant covariates by Cox regression for FFBF were prostate specific antigen (PSA), the GS, and the BED (p < 0.001), for FFM PSA (p < 0.001) and GS (p = 0.029), and for CSS PSA, the GS (p < 0.001) and the BED (p = 0.022). Prostate cancer mortality was 7/62 (15.6%) for BED ≤ 150 Gy, 18/229 (7.9%) for BED >150-200 Gy, and 20/470 (5.9%) for BED >200 Gy (p = 0.029). Long-term morbidity was not different for the two isotopes.

CONCLUSIONS

Brachytherapy boost with I-125 and Pd-103 appears equally effective yielding 10-year CSS of over 90%. I-125 may have an advantage in T3 disease. Higher doses yield the most favorable survival.

The Ratio of the Number of Biopsy Specimens to Prostate Volume (Biopsy Density) Greater Than 1.5 Improves the Prostate Cancer Detection Rate in Men Undergoing Transperineal Biopsy of the Prostate

PURPOSE

We sought to determine the minimum number of transperineal prostate mapping biopsies needed to optimize the prostate cancer detection rate.

MATERIALS AND METHODS

A total of 436 men underwent transperineal prostate mapping biopsy at 2 institutions. Biopsy density was calculated as the ratio of the total number of specimens retrieved (mean 59.4) to prostate volume (mean 44.9 cc). Associations of biopsy density with prostate specific antigen, prostate specific antigen density, cancer diagnosis and the Gleason score were tested by ANOVA and the chi-square test. Regression analysis was done to determine factors associated with a positive transperineal prostate mapping biopsy and Gleason score 7 or higher cancer.

RESULTS

Transperineal prostate mapping biopsy was positive in 299 of 436 men (68.6%). The mean number of positive cores was 7.1 (range 1 to 41) and mean biopsy density was 1.46 (range 0.39 to 3.67). The mean number of cores in positive vs negative transperineal prostate mapping biopsies was 1.61 vs 1.14 (p <0.001). Biopsy density cut points of 0.5 or less, greater than 0.5 to 1.0, greater than 1.0 to 1.5 and greater than 1.5 were associated with positive biopsy in 25%, 37.4%, 70.7% and 84.9% of patients (p <0.001). Dichotomizing biopsy density to 1.5 or less vs greater than 1.5 resulted in a positive biopsy rate of 56.4% vs 84.9% (OR 1.5, 95% CI 1.3-1.7, p <0.001). More Gleason score 6 cancers were diagnosed with higher biopsy density (94 of 158 or 59.5% vs 62 of 141 or 44.9%, p = 0.007). However, the number of positive cores with Gleason score 6 was greater in men with higher biopsy density at 4.9 vs 3.6 (p = 0.036). Prostate specific antigen (p = 0.053) and biopsy density (p = 0.012) were significant on regression analysis for positive transperineal prostate mapping biopsy and Gleason score 7+ disease.

CONCLUSIONS

Biopsy density greater than 1.5 increases the diagnosis of prostate cancer by 1.5 times, detects higher volume Gleason score 6 disease and should be considered the optimal sampling approach when performing transperineal prostate mapping biopsy.