Introduction
Prostate cancer with median lobe hyperplasia (MLH) is a relative contraindication for permanent prostate brachytherapy (PPB) because of an increased risk of post-implant dysuria and technical difficulties associated with achieving stability while implanting within the intravesical tissue. We examined treatment outcome, seed migration, and urination disorders after treatment in MLH patients in order to determine to what degree MLH implants could be stabilized.

Material and methods
Between March 2007 and December 2016, 32 patients had MLH identified radiologically on magnetic resonance imaging, and 193 patients did not have MLH (non-MLH). All patients were treated with loose seeds. In this study, seed migration was defined as a seed distant from the target (≥ 1.5 cm) and/or with no dosimetric contribution to the target. The MLH patients were divided into 2 MLH groups of mild (< 10 mm) and severe (≥ 10 mm) MLH by measuring the distance between the posterior transitional zone and the prostatic tissue protruding into the bladder. We retrospectively analyzed seed migration, dose-volume histograms (DVH), and genitourinary toxicity.

Results
MLH was classified as mild in 24 patients and severe in 8. Seed migration occurred in 61 (31.6%) of 193 non-MLH patients and 10 (31.5%) of 32 MLH patients. Implant seed migration and low-dose level of median lobe tended to be high in severe MLH cases. International Prostate Symptom Score (IPSS) peaked one month after implantation, but then resolved slowly and returned to around the pre-treatment level after one year. There were no severe complications.

Conclusions
MLH does not appear to be a strong contraindication for low-dose-rate brachytherapy. However, we found that the seed migration and degree of cold spots tended to be higher in severe MLH cases than in others; therefore, close attention when treating severe MLH cases must be paid.



中文翻译：

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接受碘 125 粒子永久前列腺近距离治疗伴 MRI 分类中叶增生患者放射性植入物迁移分析

 介绍

伴有中叶增生（MLH）的前列腺癌是永久性前列腺近距离放射治疗（PPB）的相对禁忌症，因为植入后排尿困难的风险增加，并且在植入膀胱内组织时实现稳定性相关的技术困难。我们检查了 MLH 患者治疗后的治疗结果、种子迁移和排尿障碍，以确定 MLH 植入物可以稳定到什么程度。

 材料与方法

2007年3月至2016年12月期间，32名患者经磁共振成像放射学鉴定为MLH，193名患者未患有MLH（非MLH）。所有患者均接受松散种子治疗。在本研究中，种子迁移被定义为距离目标较远（≥ 1.5 cm）和/或对目标没有剂量测定贡献的种子。通过测量后移行区与伸入膀胱的前列腺组织之间的距离，将MLH患者分为轻度（< 10 mm）和重度（≥10 mm）MLH 2个MLH组。我们回顾性分析了种子迁移、剂量体积直方图 (DVH) 和泌尿生殖毒性。

 结果

24 名患者被分类为轻度 MLH，8 名患者被分类为重度。193 名非 MLH 患者中有 61 名 (31.6%) 发生种子迁移，32 名 MLH 患者中有 10 名 (31.5%) 发生种子迁移。在严重的 MLH 病例中，植入种子迁移和中叶低剂量水平往往较高。国际前列腺症状评分（IPSS）在植入后一个月达到峰值，但随后缓慢缓解，一年后恢复到治疗前水平左右。没有出现严重的并发症。

 结论

MLH 似乎并不是低剂量率近距离放射治疗的强烈禁忌症。然而，我们发现严重 MLH 情况下的种子迁移和冷点程度往往高于其他情况；因此，在治疗严重MLH病例时必须高度重视。