case_images: PMC11236593_01
case_images: Hematoxylin-eosin and immunohistochemical staining for PD-L1 expression in pathological sections. (A) The hematoxylin-eosin staining of pathological sections revealed poorly differentiated squamous cell carcinoma with heterotypic cells arranged in nests, interstitial infiltration, and no obvious keratosis (magnification, x100). (B) The immunohistochemical PD-L1 expression test using Dako's 22C3 assay for the primary esophageal tumor showed a tumor proportion score of 0 with a combined positive score of <1 (magnification, x200).
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case_images: A 66-year-old male patient was diagnosed with upper thoracic esophageal poorly differentiated squamous cell carcinoma (cT3N2M0, stage III) ( Figure 1A ) in a local hospital in June 2020 by esophagoscopy biopsy, chest and upper abdominal computed tomography (CT), and an esophageal barium meal. The immunohistochemical PD-L1 expression test using Dako's 22C3 assay for the primary esophageal tumor showed a tumor proportion score (TPS, which is calculated as the number of PD-L1 positive tumor cells divided by the total number of all tumor cells multiplied by 100) of 0 with a combined positive score (CPS, which is calculated as the number of PD-L1 positive cells, including tumor cells, lymphocytes, and macrophages divided by the total number of viable tumor cells multiplied by 100) of <1 ( Figure 1B ).
case_images: CT images of lung metastases at baseline and after two cycles and 18 cycles of camrelizumab plus SBRT. (A), a-k: Lung window of CT images for lung metastases at baseline. (B), a-k: Lung windows of CT images of lung metastases after 2 cycles of camrelizumab plus SBRT. (C), a-k: Lung windows of CT images for lung metastases after 18 cycles of camrelizumab plus SBRT. In total, 13 metastatic nodules were located in the lungs. One nodule located in the right upper lung (Ab) and one in the right lower lung (Ag) received SBRT at 45 Gy/5 f, one day for each alternate, twelve days after the first cycle of camrelizumab. The second cycle of camrelizumab was administered 2 weeks after SBRT, and repeat thoracic CT was delivered 4 weeks later. On the repeat CT scan, the metastases that received SBRT showed fibrosis, fuzziness, and consolidation changes (Bb and Bg). For most metastases that did not receive SBRT, an obvious volume decrease and fuzzy change were observed, including one nodule that completely vanished (Bc). Other 16 cycles of camrelizumab were administered; the repeat CT showed more obvious fibrosis, fuzziness, and consolidation changes in the target nodules, and the nontarget nodule received radiation at a relatively high dose (Ca and Cf). The volume of other nontarget nodules continued to decrease, and the fuzzy change was more obvious, including another nodule that completely vanished (Cj). Red, blue, and green arrows: metastases located in the lungs at baseline and after treatment. Red and blue dotted boxes: particular areas surrounding metastases, which are magnified and displayed on the side.
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case_images: The baseline thoracic CT revealed a slightly thickened esophageal wall and 13 metastatic nodules with diameters ranging from 7 mm to 11 mm ( Figures 2A a-k) in the bilateral lungs. Twelve days later, SBRT ( Figures 3A-C ) was delivered to two nodules located in the right upper and lower lung ( Figures 2A b, g), and the prescribed dose was 45 Gy in 5 fractions, which was given every other day for each nodule alternately. Figures 2B b, g). For most of the nontarget nodules, obvious volume decreases and fuzzy changes were observed ( Figures 2B a-k), including one nodule that completely vanished ( Figure 2B c). From August 2021 to June 2023, this patient received another 23 cycles of camrelizumab, 200 mg IV on day 1, every 3-4 weeks (25 cycles in total), and thoracic and upper abdominal CT scans were taken every 3 to 4 months regularly with no oncotherapy thereafter. On December 2022, after 18 cycles of camrelizumab, repeated thoracic CT showed more obvious fibrosis, fuzziness, and consolidation changes in the target nodules, and the nontarget nodules received radiation at a quite high dose ( Figures 2C a, b, g). The volume of other nontarget nodules continued to decrease, and the fuzzy change was more obvious ( Figures 2C b-k), including another nodule that completely vanished ( Figure 2C j).
case_images: The spatial dose distribution for target and nontarget metastases of the SBRT plan. (A) The dose distribution for the target metastasis located in the right upper lung, with displayed isodoses ranging from 2250 cGy to 5500 cGy. (B) The dose distribution for the target metastasis located in the right lower lung, with the displayed isodoses ranging from 2250 cGy to 5500 cGy. (C) The dose distributions for target metastases in sagittal sections, with the displayed isodoses ranging from 2250 cGy to 5500 cGy. (D) The spatial dose distribution for target and nontarget metastases in the DDR coronal plane. Each colored nodule represents the planning volume of different target or nontarget metastases (uniformly expanded 5 mm for metastases), and the mean dose for the planning volume of each nontarget metastasis is displayed on the side (Dmean). The displayed isodoses ranged from 50 cGy to 5500 cGy. TL, target lesion; DDR, direct digital radiography. (E) The spatial dose distribution for target and nontarget metastases in the DDR sagittal plane. Each colored nodule represents the planning volume of different target or nontarget metastases. The displayed isodoses ranged from 50 cGy to 5500 cGy. TL, target lesion; DDR, direct digital radiography.
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case_images: Twelve days later, SBRT ( Figures 3A-C ) was delivered to two nodules located in the right upper and lower lung ( Figures 2A b, g), and the prescribed dose was 45 Gy in 5 fractions, which was given every other day for each nodule alternately.
case_images: The clinical course and timeline of the present case. TPS, tumor proportion score; CPS, combined positive score; IV, intravenous; SBRT, stereotactic body radiotherapy; ICI, immune checkpoint inhibitor; PFS, progression-free survival; DOR, duration of response.
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case_images: T lymphocyte counts were 124 cells/muL and 263 cells/muL, respectively, compared to 122 cells/muL and 156 cells/muL after the second cycle of camrelizumab and 148 cells/muL and 271 cells/muL after the 6th cycles of camrelizumab, respectively, and there was no subsequent lymphocyte test thereafter. The clinical course and timeline of the present case are shown in  Figure 4 .