Frequency of subclinical interstitial lung disease in COVID-19 autopsy cases: potential risk factors of severe pneumonia

Risk factors of severe coronavirus disease 2019 (COVID-19) have been previously reported; however, histological risk factors have not been defined thus far. The aim of this study was to clarify subclinical hidden interstitial lung disease (ILD) as a risk factor of severe pneumonia associated with COVID-19. We carefully examined autopsied lungs and chest computed tomography scanning (CT) images from patients with COVID-19 for interstitial lesions and then analyzed their relationship with disease severity. Among the autopsy series, subclinical ILD was found in 13/27 cases (48%) in the COVID-19 group, and in contrast, 8/65 (12%) in the control autopsy group (p = 0.0006; Fisher's exact test). We reviewed CT images from the COVID-19 autopsy cases and verified that subclinical ILD was histologically detectable in the CT images. Then, we retrospectively examined CT images from another series of COVID-19 cases in the Yokohama, Japan area between February-August 2020 for interstitial lesions and analyzed the relationship to the severity of COVID-19 pneumonia. Interstitial lesion was more frequently found in the group with the moderate II/severe disease than in the moderate I/mild disease (severity was evaluated according to the COVID-19 severity classification system of the Ministry of Health, Labor, and Welfare [Japan]) (moderate II/severe, 11/15, 73.3% versus moderate I/mild, 108/245, 44.1%; Fisher exact test, p = 0.0333). In conclusion, it was suggested that subclinical ILD could be an important risk factor for severe COVID-19 pneumonia. A benefit of these findings could be the development of a risk assessment system using high resolution CT images for fatal COVID-19 pneumonia.

Impact of concomitant idiopathic pulmonary fibrosis on prognosis in lung cancer patients: A meta-analysis

Background

Current studies showed that idiopathic pulmonary fibrosis (IPF) may lead to a poor prognosis of lung cancer. We conducted a meta-analysis to explore the impact of concomitant IPF in lung cancer and its prognostic value.

Methods

We searched the databases of PubMed, Web of Science, Embase up to Feb 10^th, 2021 for relevant researches and merged the hazard ratios (HRs) and 95% confidence intervals (CIs) to evaluate the association between concomitant IPF and overall survival (OS) in patients with lung cancer.

Results

Twelve studies involving 58424 patients were included in our meta-analysis. The results indicated that concomitant IPF was correlated with poor prognosis of lung cancer patients (HR = 1.99, 95%CI, 1.59–2.51). The association remained consistent after subgroup analysis and meta-regression stratified by study region, sample size, tumor histology, and therapy. In addition, our results were robust even after sensitivity analysis.

Conclusions

Concomitant IPF may be a prognostic factor of lung cancer, which can lead to poor survival. However, further studies were necessary for evidence in clinical application.

Correlation between preoperative 18F-FDG PET/CT findings and postoperative short-term prognosis in lung cancer patients with idiopathic interstitial pneumonia after lung resection

BACKGROUND

The present study aimed to investigate the correlation between preoperative 2-deoxy-2-[¹⁸F]fluoro-d-glucose (¹⁸F-FDG) PET/CT findings and short-term survival in lung cancer patients with idiopathic interstitial pneumonia (IIP).

METHODS

We retrospectively reviewed the data of 425 patients who underwent lung resection for non-small cell lung cancer without preoperative radiation therapy between November 2012 and October 2017. The maximum SUV (SUVmax) in the IIP area except the lung cancer site was measured in each patient.

RESULTS

Thirty-one of the 425 patients (7.3%) showed findings of IIP in chest CT. Five of the 31 patients (16.1%) developed acute exacerbation (AE) after lung resection (AE+ group). Twenty-six of the 31 patients (83.9%) did not develop AE (AE- group). In the AE+ group, ¹⁸F-FDG SUVmax in the IIP area was significantly higher (1.9 ± 0.6 vs. 2.7 ± 0.7, p = 0.02) compared with that in the AE- group. The receiver operating characteristic analysis identified an SUVmax threshold score of 2.55 (p = 0.02) for AE. There was no 90-day mortality in the patients with SUVmax < 2.55 (n = 25). On the other hand, the 90-day mortality rate in patients with SUVmax ≥ 2.55 (n = 6) was 33.3% (2 patients).

CONCLUSIONS

¹⁸F-FDG PET/CT may predict AE after lung resection and could be related to short-term survival in lung cancer patients with IIP. Further investigations are needed to improve the prognosis in patients with high SUVmax in the IIP area.

Postoperative acute exacerbation of interstitial pneumonia in pulmonary and non-pulmonary surgery: a retrospective study

BACKGROUND

Acute exacerbation of interstitial pneumonia (AE-IP) is a serious complication of pulmonary surgery in patients with IP. However, little is known about AE-IP after non-pulmonary surgery. The aim of this study was to determine the frequency of AE-IP after non-pulmonary surgery and identify its risk factors.

METHODS

One hundred and fifty-one patients with IP who underwent pulmonary surgery and 291 who underwent non-pulmonary surgery were retrospectively investigated.

RESULTS

AE-IP developed in 5 (3.3%) of the 151 patients in the pulmonary surgery group and 4 (1.4%) of the 291 in the non-pulmonary surgery group; the difference was not statistically significant. A logistic regression model showed that serum C-reactive protein (CRP) was a predictor of AE-IP in the non-pulmonary surgery group (odds ratio 1.187, 95% confidence interval 1.073-1.344, P = 0.002).

CONCLUSIONS

This is the first study to compare the frequency of AE-IP after pulmonary surgery with that after non-pulmonary surgery performed under the same conditions. The results suggest that the frequency of AE-IP after non-pulmonary surgery is similar to that after pulmonary surgery. A high preoperative C-reactive protein level is a potential risk factor for AE-IP after non-pulmonary surgery.

Incidental nonneoplastic parenchymal findings in patients undergoing lung resection for mass lesions

The prevalence of incidental nonneoplastic lung disease in patients undergoing resection for mass lesions is unknown. We determined the prevalence and characteristics of parenchymal findings in patients with lung nodules, aiming to increase awareness of findings that could potentially impact patient management. A total of 397 patients with benign or malignant mass lesions with available presurgical chest computed tomography scans resected between January 2001 and July 2015 were included. Retrospective histologic assessment of parenchymal abnormalities in at least 1 section of grossly normal lung was performed for each case by 2 pulmonary pathologists and correlated with original pathology reports, clinical history, and radiologic findings. A total of 233 women and 164 men underwent resections for carcinomas (78%) or benign nodules (22%). One hundred one (25%) patients showed parenchymal abnormalities, including 14 patients with multiple findings. The most common abnormal findings were fibrotic interstitial changes (10%), including usual interstitial pneumonia (1%), followed by granulomatous processes (8%). Other findings included aspiration (4%), intravascular thrombi (2%), Langerhans cell histiocytosis (1.5%), constrictive bronchiolitis (1%), atypical lymphoid infiltrates (1%), and amyloidosis (0.5%). Abnormalities were more likely to have been documented in the original pathology report by pulmonary pathologists (68%) than by general pathologists (15%) (P < .0001). Cases with histologic parenchymal abnormalities were more likely to show radiologic interstitial lung abnormalities than those without (16% versus 5%; P = .001). Evaluation of background lung parenchyma may yield valuable and unanticipated information in patients undergoing surgical resections for lung masses that may correlate with radiographic interstitial lung abnormalities and influence clinical management.

Measuring Surgery Outcomes of Lung Cancer Patients with Concomitant Pulmonary Fibrosis: A Review of the Literature

Idiopathic pulmonary fibrosis (IPF), the most common form of idiopathic interstitial pneumonias, often progresses to restrictive respiratory disturbance and mortality, typically within 10 years. IPF frequently coexists with lung cancer, and the combination of these two disease entities is far more difficult to treat than either lung cancer or IPF alone. In particular, surgery for lung cancer with IPF in the background increases postoperative morbidity and mortality by exacerbating pre-existing IPF, i.e., acute exacerbation of IPF (AEIPF). Furthermore, the long-term outcome after lung cancer surgery is considerably worsened by the presence of IPF. We present here a comprehensive review of AEIPF and the long-term outcomes after surgery.