Bryan Richard T, Collins Stuart I, Daykin Mark C, Zeegers Maurice P, Cheng K K, Wallace D Michael A, Sole Graham M
Department of Public Health, Epidemiology and Biostatistics, School of Population Sciences, University of Birmingham, Birmingham, UK.
Ann R Coll Surg Engl. 2010 Sep;92(6):519-24. doi: 10.1308/003588410X12664192076935. Epub 2010 Jun 1.
Bladder cancer recurrence occurs via four mechanisms - incomplete resection, tumour cell re-implantation, growth of microscopic tumours, and new tumour formation. The first two mechanisms are influenced by clinicians before and immediately after resection; the remaining mechanisms have the potential to be influenced by chemopreventive agents. However, the relative importance and timing of these mechanisms is currently unknown. Our objective was to postulate the incidence and timing of these mechanisms by investigating the location of bladder cancer recurrences over time.
The topographical locations of tumours and their recurrences were analysed retrospectively for 169 patients newly-diagnosed with Ta/T1 bladder cancer, with median follow-up of 33.8 months. Tumours were assigned to one or more of six bladder sectors, and time to recurrence and location of recurrences were recorded.
Median time to first tumour recurrence was 40 months. Median times between subsequent recurrences were 6.6, 7.9, 8.0 and 6.6 months for recurrences 1 to 2, 2 to 3, 3 to 4, and 4 to 5, respectively. The risk of first tumour recurrence in any given bladder sector increased by nearly 4-fold if the primary tumour was resected from that sector (P < 0.001); this association was not significant for subsequent recurrences. The proportion of tumour recurrences in multiple bladder sectors increased from 13% for the first recurrence to 100% for recurrence seven onwards.
First tumour recurrence appears different to subsequent recurrences; incomplete resection and tumour cell reimplantation may dominate at this time-point. Only later does genuine new tumour formation appear to increase in importance. This has important implications for clinical trials, especially those involving chemopreventive agents.
膀胱癌复发通过四种机制发生——切除不完全、肿瘤细胞再植入、微小肿瘤生长和新肿瘤形成。前两种机制受临床医生在切除前及切除后即刻的影响；其余机制有可能受化学预防剂的影响。然而，这些机制的相对重要性和发生时间目前尚不清楚。我们的目的是通过研究膀胱癌复发随时间的位置来推测这些机制的发生率和发生时间。
对169例新诊断为Ta/T1期膀胱癌的患者进行回顾性分析，分析肿瘤及其复发的地形位置，中位随访时间为33.8个月。肿瘤被分配到六个膀胱区域中的一个或多个区域，并记录复发时间和复发位置。
首次肿瘤复发的中位时间为40个月。第1次至第2次、第2次至第3次、第3次至第4次和第4次至第5次复发之间的中位时间分别为6.6、7.9、8.0和6.6个月。如果原发肿瘤是从某一膀胱区域切除的，那么该区域首次肿瘤复发的风险增加近4倍（P<0.001）；这种关联在随后的复发中不显著。多个膀胱区域肿瘤复发的比例从首次复发时的13%增加到第7次及以后复发时的100%。
首次肿瘤复发似乎与随后的复发不同；此时切除不完全和肿瘤细胞再植入可能占主导地位。只有在后来真正的新肿瘤形成的重要性才似乎增加。这对临床试验具有重要意义，尤其是那些涉及化学预防剂的试验。
