Oligometastatic disease has been proposed as an intermediate state between localised and systemically metastasised disease. In the absence of randomised phase 3 trials, early clinical studies show improved survival when radical local therapy is added to standard systemic therapy for oligometastatic disease. However, since no biomarker for the identification of patients with true oligometastatic disease is clinically available, the diagnosis of oligometastatic disease is based solely on imaging findings. A small number of metastases on imaging could represent different clinical scenarios, which are associated with different prognoses and might require different treatment strategies. 20 international experts including 19 members of the European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer OligoCare project developed a comprehensive system for characterisation and classification of oligometastatic disease. We first did a systematic review of the literature to identify inclusion and exclusion criteria of prospective interventional oligometastatic disease clinical trials. Next, we used a Delphi consensus process to select a total of 17 oligometastatic disease characterisation factors that should be assessed in all patients treated with radical local therapy for oligometastatic disease, both within and outside of clinical trials. Using a second round of the Delphi method, we established a decision tree for oligometastatic disease classification together with a nomenclature. We agreed oligometastatic disease as the overall umbrella term. A history of polymetastatic disease before diagnosis of oligometastatic disease was used as the criterion to differentiate between induced oligometastatic disease (previous history of polymetastatic disease) and genuine oligometastatic disease (no history of polymetastatic disease). We further subclassified genuine oligometastatic disease into repeat oligometastatic disease (previous history of oligometastatic disease) and de-novo oligometastatic disease (first time diagnosis of oligometastatic disease). In de-novo oligometastatic disease, we differentiated between synchronous and metachronous oligometastatic disease. We did a final subclassification into oligorecurrence, oligoprogression, and oligopersistence, considering whether oligometastatic disease is diagnosed during a treatment-free interval or during active systemic therapy and whether or not an oligometastatic lesion is progressing on current imaging. This oligometastatic disease classification and nomenclature needs to be prospectively evaluated by the OligoCare study.

中文翻译：

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少转移性疾病的特征和分类：欧洲放射疗法和肿瘤学会和欧洲癌症研究与治疗组织的共识建议。

已经提出了抑制卵巢转移性疾病作为局部和全身转移性疾病之间的中间状态。在缺乏随机的3期临床试验的情况下，早期的临床研究表明，将根治性局部治疗与标准的全身治疗相结合，可改善生存率。然而，由于临床上没有可用于鉴定真正的少转移性疾病患者的生物标记物，因此，仅根据影像学发现即可诊断出少转移性疾病。影像学上的少量转移可能代表不同的临床情况，这与不同的预后相关，可能需要不同的治疗策略。20名国际专家，包括欧洲放射疗法和肿瘤学学会的19名成员以及欧洲的OligoCare癌症研究和治疗组织的项目，开发了一套综合的系统，用于寡转移性疾病的表征和分类。我们首先对文献进行了系统的综述，以确定前瞻性介入性少转移性疾病临床试验的纳入和排除标准。接下来，我们使用Delphi共识方法选择了总共17种低转移性疾病特征因素，在临床试验的内部和外部，应对所有接受过局部局部治疗的低转移性疾病患者进行评估。使用第二轮的Delphi方法，我们建立了一个针对转移性疾病分类的决策树以及一个命名法。我们同意将低转移性疾病作为总括性术语。将诊断为低转移性疾病之前的多转移性疾病病史用作区分诱导性低转移性疾病（以前的多转移性疾病史）和真正的低转移性疾病（无多转移性疾病史）的标准。我们进一步将真正的低转移性疾病细分为重复性低转移性疾病（以前的低转移性疾病病史）和新的低转移性疾病（首次诊断为低转移性疾病）。在新发性低转移性疾病中，我们区分了同步性和异时性低转移性疾病。我们将最终分类分为寡聚递归，寡聚递进和寡聚持久性，考虑是否在无治疗间隔期间或在积极的全身治疗期间诊断出了低转移性疾病，以及当前影像学上是否正在发展低转移性病变。这种低转移性疾病的分类和命名需要通过OligoCare研究进行前瞻性评估。