Humbert Olivier, Chardin David
Department of Nuclear Medicine, Centre Antoine-Lacassagne, Université Côte d'Azur, Nice, France.
TIRO-UMR E 4320, Université Côte d'Azur, Nice, France.
Front Oncol. 2020 Sep 18;10:566297. doi: 10.3389/fonc.2020.566297. eCollection 2020.
When evaluating metastatic tumor response to systemic therapies, dissociated response is defined as the coexistence of responding and non-responding lesions within the same patient. Although commonly observed on interim whole-body imaging, the current response criteria in solid cancer do not consider this evolutive pattern, which is, by default, assimilated to progression. With targeted therapies and chemotherapies, dissociated response is observed with different frequencies, depending on the primary cancer type, treatment, and imaging modality. Because FDG PET/CT can easily assess response on a lesion-by-lesion basis, thus quickly revealing response heterogeneity, a PET/CT dissociated response has been described in up to 48% of women treated for a metastatic breast cancer. Although some studies have underlined a specific prognostic of dissociated response, it has always ended up being described as an unfavorable prognostic pattern and therefore assimilated to the "Progressive Disease" category of RECIST/PERCIST. This dichotomous imaging report (response vs. progression) provides a simple information for clinical decision-support, which probably explains the relatively low consideration for the dissociated response pattern to chemotherapies and targeted therapies until now. With immune checkpoint inhibitors, this paradigm is quickly changing. Dissociated response is observed in around 10% of advanced lung cancer patients and appears to be associated to treatment efficiency. Indeed, for this subset of patients, a clinical benefit of immunotherapy and favorable prognosis are usually observed. This specific pattern should therefore be considered in the future immunotherapy-adapted criteria for response evaluation using CT and PET/CT, and specific clinical managements should be evaluated for this response pattern.
在评估转移性肿瘤对全身治疗的反应时，分离反应被定义为同一患者体内存在反应性病变和无反应性病变。尽管在中期全身成像中经常观察到这种情况，但实体癌目前的反应标准并未考虑这种动态变化模式，默认情况下，这种模式被视为疾病进展。对于靶向治疗和化疗，分离反应的观察频率因原发癌类型、治疗方法和成像方式而异。由于氟代脱氧葡萄糖正电子发射断层扫描/计算机断层扫描（FDG PET/CT）能够轻松地逐个评估病变的反应，从而迅速揭示反应的异质性，在接受转移性乳腺癌治疗的女性中，高达48%的患者出现了PET/CT分离反应。尽管一些研究强调了分离反应的特定预后意义，但它最终总是被描述为一种不良预后模式，因此被归为实体瘤疗效评价标准（RECIST）/实体瘤疗效评价标准更新版（PERCIST）中的“疾病进展”类别。这种二分法的成像报告（反应与进展）为临床决策支持提供了简单信息，这可能解释了到目前为止，对于化疗和靶向治疗的分离反应模式相对较少考虑的原因。随着免疫检查点抑制剂的出现，这种模式正在迅速改变。在大约10%的晚期肺癌患者中观察到了分离反应，并且似乎与治疗效果相关。事实上，对于这部分患者，通常观察到免疫治疗具有临床益处且预后良好。因此，在未来使用CT和PET/CT进行免疫治疗适应性反应评估的标准中应考虑这种特定模式，并且应对这种反应模式进行具体的临床管理评估。
