Manual vs. automated implantation of seeds in prostate brachytherapy: Oncologic results from a single-center study

The objective of this study was to study survival and tolerance of prostate cancer patients treated with ¹²⁵I permanent interstitial brachytherapy by automated vs. manual implantation of seeds.

Between 2002 and 2010, 349 selected patients were treated with ¹²⁵I brachytherapy by the same team: from 2002 to April 2005, 65 patients with linked seeds and then 284 patients treated using Nucletron First System automated implantation. We analyzed biochemical recurrence-free survival (bRFS) rates and toxicities (univariate and multivariate analyses).

Two hundred seventy-seven (79.4%) and 69 patients (19.8%) with low- and intermediate-risk disease were treated, respectively (median follow-up: 64 months). The 5-year bRFS rate was 93.1% (95% confidence interval 89.3-95.6) for the entire cohort. The 5-year bRFS rates were 93.4% and 91.7% for patients with low- and intermediate-risk disease, respectively (p = 0.42). In univariate and multivariate analyses, there was no statistically significant difference in the 5-year bRFS rate depending on the implantation technique (93.1% vs. 91.8%, respectively, for automated and linked seeds; p = 0.53). In univariate analysis, only D₉₀ prostate (dose delivered to 90% of the prostate) <140 Gy (p = 0.01), lack of prostate-specific antigen bounce (p = 0.008), and nadir prostate-specific antigen >0.11 (p = 0.01) were predictive factors for bRFS. We observed Grade 3 urethritis in 7 patients (2%), urinary incontinence in 2 patients (0.7%), and Grade 4 proctitis in 2 patients (0.7%).

In this large single-center series, brachytherapy for selected localized prostate cancer achieved excellent rates of biochemical control at 5 years (93.1%) with an acceptable toxicity profile, irrespective of the implantation technique used.