Royal Marsden Hospital, London, UK; Croydon University Hospital, UK; Imperial College London, UK.
Radboud University Medical Centre, Nijmegen, the Netherlands.
Eur J Cancer. 2020 Mar;128:1-6. doi: 10.1016/j.ejca.2019.12.025. Epub 2020 Mar 5.
Rectal cancer can spread in a number of ways which have been previously recognised and validated as prognostic markers. These routes of spread are not adequately recognised in the stage grouping of the tumour-node-metastasis system, which focuses predominantly on the depth of invasion and nodal status, thus limiting its prognostic accuracy. Tumour spread involving veins occurs in 40% of patients. Venous channels have greater direct access to distant sites by means of a vascular 'anatomical highway'. This rapid spread of tumour cells to distant metastatic sites by veins cannot occur by means of lymph node pathways. Thus, lymph nodes have been overestimated in their importance. Distinction between local tumour spread (lymph node metastases, perineural and lymphatic invasion) and tumour spread mediated by a direct vascular pathway to distant dissemination (extramural venous invasion and tumour deposits) must be made as the implications for prognosis and choice of treatment are not likely to be equal. Improved precision of radiological and pathological assessment is needed to scrutinise and carefully document each route of tumour spread. Only with this accurate information will it be possible to correctly weight each feature and develop a more prognostically accurate staging method that would allow separation of true high- and low-risk groups and subsequent improvements in patient care.
直肠癌可以通过多种途径扩散，这些途径以前已经被认识和验证为预后标志物。这些传播途径在肿瘤-淋巴结-转移系统的分期分组中没有得到充分的认识，该系统主要侧重于浸润深度和淋巴结状态，从而限制了其预后准确性。40%的患者存在静脉受累的肿瘤扩散。静脉通道通过血管“解剖高速公路”更直接地到达远处部位。肿瘤细胞通过静脉向远处转移部位的这种快速扩散不能通过淋巴结途径发生。因此，淋巴结的重要性被高估了。必须区分局部肿瘤扩散（淋巴结转移、神经周围和淋巴管浸润）和通过直接血管途径向远处播散的肿瘤扩散（壁外静脉侵犯和肿瘤沉积），因为这对预后和治疗选择的影响可能并不相同。需要提高影像学和病理学评估的精度，以仔细检查和详细记录肿瘤扩散的每一种途径。只有通过这种准确的信息，才有可能正确地权衡每个特征，并开发出更具预后准确性的分期方法，从而将真正的高风险和低风险组分开，并随后改善患者的护理。
