PMC8239433_01
Disease status timeline and PET/CT scan of primary and metastatic lesions accompanied by treatment regimens. CN, cytoreductive nephrectomy; RT, radiotherapy; PET/CT, positron emission tomography-computed tomography/computed tomography; PD, progressive disease; PR, partial response; Point-in-time filled with color represents continuous use of Camrelizumab.
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Lumbar magnetic resonance imaging (MRI) highlighted the existence of a soft mass near the fifth lumbar vertebra (L5) ( Figure 1 ). The patient continued Camrelizumab treatment, resulting in a second abscopal effect which showed that the superior lobe of left lung metastasis had shrunk ( Figure 1 ). However, the number of monocytes and the macrophage-to-lymphocyte ratio (MLR) peaked during radiotherapy for lung metastasis, which may be correlated with subsequent pseudoprogression ( Figures 1  and  4 ).
FFPE tissue photomicrograph from metastatic lesion stained for negative PD-L1 assessment. PD-L1, programmed cell death receptor-ligand 1.
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Programmed cell death receptor ligand 1 (PD-L1) expression tests were negative ( Figure 2 ). On November 22, 2019, oligoprogressive lesion-targeted radiotherapy was commenced at 45 Gy in 15 fractions with an MLR peak during radiation ( Figure 2 ).
Hypothesis for the mechanism of Camrelizumab combined with CN and RT. RT destroys tumor cells so that more tumor-associated antigens can be released and recognized by tissue-resident DCs, accelerating the activation of T cells which increases the rate of activated T cells. With CN decreasing the TB, enough Camrelizumab could combine with PD-L1 expressed on tumor cells, so that T cells avoid being suppressed and work. During Camrelizumab prescription, radiation may change the microenvironment which might convert more M0-macrophages into M1-macrophages. More activated T cells and M1-macrophages wandered in blood vessels, which can account for pseudoprogression and abscopal effect. CN, cytoreductive nephrectomy; RT, radiotherapy; DCs, dendritic cells; TB, tumor burden; PD-L1, programmed cell death receptor-ligand 1.
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However, the number of monocytes and the macrophage-to-lymphocyte ratio (MLR) peaked during radiotherapy for lung metastasis, which may be correlated with subsequent pseudoprogression ( Figures 1  and  4 ).