Clinical Features
Figure 1 shows the flowchart of screening the patients. A total of 32 (4.7%) patients with CIP (mean age: 64.1 ± 10.3 years; age range: 43–82 years) were included in this study, including 26 (81.2%) males (mean age: 64.0 ± 10.3 years; age range: 43–82 years) and 6 (18.8%) females (mean age: 64.5 ± 11.3 years; age range: 45–78 years). Among these patients, 25 (78.1%) had a history of smoking, with an average of 40.4 ± 31.5 pack-years (range: 22.2–58.6 pack-years). Of the 32 patients, 21 (65.6%) patients were administered pembrolizumab, 6 (18.8%) were administered nivolumab, 2 (6.3%) were administered sintilimab, 2 (6.3%) were administered durvalumab, and 1 (3.1%) was administered nivolumab and ipilimumab. 32 CIP patients received steroid treatment, after which, 23 (71.9%) patients survived, including 17 patients' condition improved (Fig. 2), 6 patients' condition worsened. In addition, 9 (28.1%) patients died. Clinical features are detailed in Table 1.
Table 1
Baseline Characteristics of 32 CIP Patients
Characteristics
|
Datum
|
age of all 32 patients (y), mean ± SD
|
64.1 ± 10.3
|
age of 26 male patients (y), mean ± SD
|
64.0 ± 10.3
|
age of 6 female patients (y), mean ± SD
|
64.5 ± 11.3
|
No. of current smokers, n (%)
|
25 (78.1)
|
No. of nonsmokers, n (%)
|
7 (21.9)
|
No. of pack-years in the 21 patients who smoked,mean ± SD
|
40.4 ± 31.5
|
Symptoms, n (%)
|
|
Cough
|
17 (53.1)
|
Dyspnea
|
29 (90.6)
|
Fever/Fatigue/Chest pain/No symptom
|
11 (11.3)
|
Tumor location, n (%)
|
|
Left lung
|
13 (40.6)
|
Right lung
|
19 (59.4)
|
Tumor histology, n (%)
|
|
squamous
|
9 (28.1)
|
adenocarcinoma
|
19 (59.4)
|
others
|
4 (12.5)
|
Initial tumor stage, n (%)
|
|
I-II
|
1 (3.1)
|
III–V
|
31 (96.9)
|
Tumor differentiation, n (%)
|
|
High-high to medium-medium
|
5 (15.6)
|
Medium to low-low
|
22 (68.8)
|
Other
|
5 (15.6)
|
ICI agents, n (%)
|
|
pembrolizumab
|
21 (65.6)
|
Nivolumab
|
6 (18.8)
|
sintilimab/durvalumab/nivolumab + ipilimumab
|
5 (15.6)
|
Surgery, n (%)
|
7 (21.9)
|
Chemotherapy, n (%)
|
20 (62.5)
|
Radiotherapy, n (%)
|
8 (25.0)
|
Radiation pneumonitis, n (%)
|
2 (6.3)
|
Prognosis, n (%)
|
|
Survival
|
23 (71.9)
|
Death
|
9 (28.1)
|
Radiographic Patterns of CIP
The chest CT patterns of the 32 patients with CIP included GGO (29 patients, 90.6%; Fig. 3A), reticulation (14 patients, 43.8%; Fig. 3B), consolidation (12 patients, 37.5%; Fig. 3C), nodularity (8 patients, 25.0%; Fig. 3D), bronchitis (7 patients, 21.9%; Fig. 3E), pleural effusion (2 patients; 6.3%), and among which 5 (15.6%; Fig. 3F) patients showed PTI features. The radiographic patterns of CIP included OP-like pattern (11 patients, 34.4%; Fig. 4A), NSIP-like pattern (11 patients, 34.4%; Fig. 4B), HP-like pattern (2 patients, 6.3%; Fig. 4C), and AIP-like pattern (1 patient, 3.1%; Fig. 4D).
Difference in Radiographic Patterns of Early-onset and Late-onset CIP
According to the occurrence time of CIP after ICI treatment, the patients were categorized into early-onset and late-onset CIP groups. In the early-onset CIP group, the chest CT patterns included GGO (13 patients, 92.9%), consolidation (7 patients, 50.0%), reticulation (5 patients, 35.7%), nodularity (5 patients, 35.7%), and bronchitis (3 patients, 21.4%); whereas, in the late-onset CIP group, the chest CT patterns included GGO (16 patients, 88.9%), reticulation (9 patients, 50.0%), consolidation (5 patients, 27.8%), nodularity (3 patients, 16.7%), bronchitis (4 patients, 22.2%), and pleural effusion (2 patients, 11.1%), indicating that there was no statistical difference in the radiographic patterns between both the groups (P > 0.05).
The radiographic patterns of early-onset CIP included OP-like pattern (7 patients, 50.0%), NSIP-like pattern (2 patients, 14.3%), HP-like pattern (1 patient, 7.1%), AIP-like pattern (one patient, 7.1%), and others (3 patients, 21.4%); whereas, the radiographic patterns of late-onset CIP included OP-like pattern (4 patients, 22.2%), NSIP-like pattern (9 patients, 50.0%), HP-like pattern (1 patient, 5.6%), and others (4 patients, 22.2%), thereby indicating that there was no statistical difference in the radiographic patterns between both the groups (P > 0.05).
According to the grading system of NCCN, there was one patient with grades 1–2 CIP (7.1%) and 13 patients with grades 3–4 CIP (92.9%) in the early-onset group. Whereas, in the late-onset group, 9 patients had grades 1–2 CIP (50.0%) and 9 patients had grades 3–4 (50.0%), Here as well, no statistical difference was observed in the CIP grading between both the groups (P < 0.05). In the early-onset group, 7 patients (50.0%) survived and 7 patients (50.0%) died; whereas, in the late-onset group, 16 patients (88.9%) survived and 2 patients (11.1%) died, indicating a statistical difference in the overall survival (OS) between both the groups (P < 0.05; Table 2 and Fig. 5).
Table 2
Radiographic patterns of 14 early-onset CIPs and 18 late-onset CIPs
|
Overall
N = 32
|
Early-onset CIP
N = 14
|
Late-onset CIP
N = 18
|
P
|
CIP location, n (%)
|
|
|
|
|
Bilateral
|
25 (78.1)
|
10 (71.4)
|
15 (83.3)
|
0.459*
|
Left
|
4 (12.5)
|
3 (21.4)
|
1 (5.6)
|
|
Right
|
3 (9.4)
|
1 (7.2)
|
2 (11.1)
|
|
Number of lobes involved, n (%)
|
|
|
|
|
1–3
|
10 (31.3)
|
5 (35.7)
|
5 (27.8)
|
0.712*
|
4–5
|
22 (68.7)
|
9 (64.3)
|
13 (77.2)
|
|
CT findings at onset of CIP, n (%)
|
|
|
|
0.598*
|
Ground glass opacity
|
29 (90.6)
|
13 (92.9)
|
16 (88.9)
|
|
Consolidation
|
12 (37.5)
|
7 (50.0)
|
5 (27.8)
|
|
Reticulation
|
14 (43.8)
|
5 (35.7)
|
9 (50.0)
|
|
Bronchitis/Nodularity
|
15 (46.9)
|
8 (57.1)
|
7 (38.9)
|
|
Pleural effusion
|
2 (6.3)
|
0 (0)
|
2 (11.1)
|
|
Overall pattern of ILD, n (%)
|
|
|
|
0.096*
|
OP-like pattern
|
11 (34.4)
|
7 (50.0)
|
4 (22.2)
|
|
NSIP-like pattern
|
11 (34.4)
|
2 (14.3)
|
9 (50.0)
|
|
AIP/HP/Others-like pattern
|
10 (31.3)
|
5 (35.7)
|
5 (27.8)
|
|
Grades of CIP, n (%)
|
|
|
|
|
1–2
|
10 (31.3)
|
1 (7.1)
|
9 (50.0)
|
0.019*
|
3–4
|
22 (68.7)
|
13 (92.9)
|
9 (50.0)
|
|
Prognosis, n (%)
|
|
|
|
|
Survival
|
23 (71.9)
|
7 (50.0)
|
16 (88.9)
|
0.022*
|
Dead
|
9 (28.1)
|
7 (50.0)
|
2 (11.1)
|
|
* Fisher exact test |