Ex-vivo 1.5T MR Imaging versus CT in Estimating the Size of the Pathologically Invasive Component of Lung Adenocarcinoma Spectrum Lesions

PURPOSE

The purpose of this study was to investigate whether ex-vivo MRI enables accurate estimation of the invasive component of lung adenocarcinoma.

METHODS

We retrospectively reviewed 32 patients with lung adenocarcinoma who underwent lung lobectomy. The specimens underwent MRI at 1.5T. The boundary between the lesion and the normal lung was evaluated on a 5-point scale in each three MRI sequences, and a one-way analysis of variance and post-hoc tests were performed. The invasive component size was measured histopathologically. The maximum diameter of each solid component measured on CT and MR T1-weighted (T1W) images and the maximum size obtained from histopathologic images were compared using the Wilcoxon signed-rank test. Inter-reader agreement was evaluated using intraclass correlation coefficients (ICC).

RESULTS

T1W images were determined to be optimal for the delineation of the lesions (P < 0.001). The histopathologic invasive area corresponded to the area where the T1W ex-vivo MR image showed a high signal intensity that was almost equal to the intravascular blood signal. The maximum diameter of the solid component on CT was overestimated compared with the maximum invasive size on histopathology (mean, 153%; P < 0.05), while that on MRI was evaluated mostly accurately without overestimation (mean, 108%; P = 0.48). The interobserver reliability of the measurements using CT and MRI was good (ICC = 0.71 on CT, 0.74 on MRI).

CONCLUSION

Ex-vivo MRI was more accurate than conventional CT in delineating the invasive component of lung adenocarcinoma.

Clinical and imaging features of interstitial lung disease in cancer patients treated with trastuzumab deruxtecan

BACKGROUND

Interstitial lung disease/pneumonitis (ILD/pneumonitis) has been identified as a drug-related adverse event of special interest of trastuzumab deruxtecan (T-DXd), but there were a few reports of T-DXd-related ILD/pneumonitis in clinical practice.

METHODS

Between May 25, 2020 (the launch of T-DXd in Japan) and February 24, 2022, there were 287 physician-reported potential ILD/pneumonitis cases from the Japanese post-marketing all-case surveillance. By February 27, 2022, an independent adjudication committee assessed 138 cases and adjudicated 130 cases as T-DXd-related ILD/pneumonitis. The clinical features and imaging characteristics of these cases were evaluated.

RESULTS

The majority of adjudicated T-DXd-related ILD/pneumonitis cases were grade 1 or 2 (100/130, 76.9%). The most common radiological pattern types observed were organizing pneumonia patterns (63.1%), hypersensitivity pneumonitis patterns (16.9%), and diffuse alveolar damage (DAD) patterns (14.6%). Eleven cases (8.5%) from 130 resulted in death; the majority of these (8/11, 72.7%) had DAD patterns. The overall proportion of recovery (including the outcomes of recovered, recovered with sequelae, and recovering) was 76.9%, and the median time to recovery was 83.5 days (interquartile range: 42.25-143.75 days). Most cases (59/71, 83.1%) that were treated with corticosteroids were considered responsive to treatment.

CONCLUSIONS

This is the first report to evaluate T-DXd-related ILD/pneumonitis cases in clinical practice. Our findings are consistent with previous reports and suggest that patients with DAD patterns have poor outcomes. Evaluation of a larger real-world dataset may further identify predictors of clinical outcome.

Distinct Prognostic Impact of PET Findings Based on Radiological Appearance in Clinical Stage IA Lung Adenocarcinoma

INTRODUCTION

Although solid appearance on computed tomography and positive findings on positron emission tomography (PET) have been both associated with poor outcome in lung adenocarcinoma, the extent to which these findings overlap is unknown. This study aimed to determine the differences in prognostic significance of PET findings in part-solid nodules (PSNs) and solid nodules.

MATERIALS AND METHODS

We retrospectively investigated 417 patients with clinical stage IA adenocarcinoma who underwent curative resection between 2010 and 2017. We compared disease-free survival (DFS), cumulative incidence of disease recurrence (CIR) and clinicopathological characters between PET-positive and negative groups among PSNs and solid nodules, respectively. We used 2.5 as a cut-off value of maximum standardized uptake value (SUV max).

RESULTS

In PSNs (n = 235), PET-positive group (n = 59) showed more aggressive features in several clinicopathological variables, poorer DFS (P < .001) and higher CIR (P < .001) than PET-negative group (n = 176). In contrast, in solid nodules (n = 182), DFS (P = .521) and CIR (P = .311) were not significantly different between PET-positive (n = 128) and negative groups (n = 54). SUV max was proved to be the independent prognostic factor of DFS by multivariate analysis (HR, 1.155; 95% CI, 1.036-1.287) only in PSNs.

CONCLUSION

These findings showed distinct impact on prognosis of PET findings between PSNs and solid nodules. PET-positive finding was more important prognostic factor in PSNs than in solid nodules among clinical stage IA lung adenocarcinoma.

Prognostic stratification according to size and dominance of radiologic solid component in clinical stage IA lung adenocarcinoma

Introduction

Although several studies have investigated the prognostic significance of the radiographic appearance of stage IA lung adenocarcinoma, the prognostic impact of solid component size or consolidation-to-tumor ratio (CTR) of part-solid nodules (PSNs) still remains controversial. This study aimed to clarify the combined prognostic impact of the mentioned radiographic features of PSNs and compare it with that of pure solid nodules in the current TNM classification.

Methods

We retrospectively investigated 1014 patients with clinical stage IA (TNM eighth edition) adenocarcinoma who underwent curative resection. Overall survival (OS) and pathologic characteristics of pure solid nodules, solid-dominant PSNs (CTR > 0.5), and ground-glass opacity (GGO)-dominant PSNs (CTR ≤ 0.5) were compared according to T category.

Results

Patients with pure solid nodules (297 cases) had significantly shorter OS compared with those with PSNs (717 cases) (p < 0.001) but a marginal difference compared with those with solid-dominant PSNs (286 cases) (p = 0.051). No significant difference in OS was found according to T category in those with GGO-dominant PSNs (431 cases). Patients with cT1b and T1c solid-dominant PSNs had significantly worse prognosis compared with those with other PSNs and had comparable prognosis with those with cT1b pure solid nodules (p = 0.892). Higher frequency of nodal and lymphovascular involvement and pathologic upstaging was observed with T category progression in solid-dominant PSNs.

Conclusions

An hierarchy of prognosis and pathologic malignant characteristics was observed according to T category in patients with solid-dominant PSNs but not in those with GGO-dominant PSNs, suggesting the importance of classifying PSNs on the basis of solid component size and CTR for accurate prognostic comparison with pure solid nodules.

Relationship between the three-dimensionally measured tumor doubling time of lung cancer and underlying interstitial lung disease: A retrospective case-control study

OBJECTIVE

The coexistence of interstitial lung disease (ILD) is associated with poor prognosis in patients with lung cancer. The tumor doubling time (TDT) of lung cancer reflects cancer aggressiveness and is related to its prognosis. However, the relationship between the TDT of lung cancer and underlying ILD has not been fully evaluated. This study aimed to identify this crucial relationship.

MATERIALS AND METHODS

Patients with lung cancer who underwent surgery between 2007 and 2020 were reviewed retrospectively. The propensity score matching method was used to balance the characteristics of patients with ILD (n = 100) and those without ILD (n = 100). TDT was calculated based on the difference of three-dimensional volumes defined from the two-time CT scans before surgery. We compared the TDT of lung cancer and other characteristics between the two groups.

RESULTS

The median TDT of all patients was 149 days. The TDT was significantly shorter in patients with ILD (134 days) than in those without (204 days). The rate of short-term tumor enlargement (TDT < 90 days) was significantly higher in patients with ILD than in those without ILD, and ILD was an independent factor related to short-term tumor enlargement (odds ratio, 2.30; p = 0.015). We focused on 25 patients with usual interstitial pneumonitis (UIP) findings of patients with ILD. However, the presence of the UIP pattern was not related to the TDT among patients with ILD.

CONCLUSION

ILD was an independent predictor of short-term tumor enlargement in lung cancer patients, regardless of the presence of the UIP pattern.

Radiographic features and poor prognostic factors of interstitial lung disease with nivolumab for non-small cell lung cancer

Nivolumab can cause interstitial lung disease (ILD), which may be fatal; however, mortality risk factors have not been identified. This postmarketing study evaluated the poor prognostic factors of ILD in nivolumab-treated patients with non-small cell lung cancer (NSCLC) in Japan. Clinical and chest imaging findings for each ILD case were assessed by an expert central review committee, and prognosis was evaluated by radiographic findings, including the presence/absence of peritumoral ground-glass opacity (peritumoral-GGO). Poor prognostic factors were identified by univariate and multivariate Cox regression analysis. Of the 238 patients with nivolumab-induced ILD, 37 died. The main radiographic patterns of ILD were cryptogenic organizing pneumonia/chronic eosinophilic pneumonia-like (53.4%), faint infiltration pattern/acute hypersensitivity pneumonia-like (20.2%), diffuse alveolar damage (DAD)-like (10.9%), and nonspecific interstitial pneumonia-like (6.3%). The main poor prognostic factors identified were DAD-like pattern (highest hazard ratio: 10.72), ≤60 days from the start of nivolumab treatment to the onset of ILD, pleural effusion before treatment, lesion distribution contralateral or bilateral to the tumor, and abnormal change in C-reactive protein (CRP) levels. Of the 37 deaths due to ILD, 17 had DAD-like radiographic pattern, three had peritumoral-GGO, and five had a change in radiographic pattern from non-DAD at the onset to DAD-like. Patients with NSCLC who develop ILD during nivolumab treatment should be managed carefully if they have poor prognostic factors such as DAD-like radiographic pattern, onset of ILD ≤60 days from nivolumab initiation, pleural effusion before nivolumab treatment, lesion distribution contralateral or bilateral to the tumor, and abnormal changes in CRP levels.

Treatment and relapse of interstitial lung disease in nivolumab-treated patients with non-small cell lung cancer

Nivolumab, a human monoclonal antibody against programmed death‐1, is approved for the treatment of non–small cell lung cancer (NSCLC). Although nivolumab is generally well tolerated, it can cause interstitial lung disease (ILD), a rare but potentially fatal immune‐related adverse event. Currently, there are limited data available on the treatment of nivolumab‐induced ILD and its outcome. This retrospective cohort study based on a post–marketing study described the treatment of nivolumab‐induced ILD and its outcome in NSCLC patients in Japan through the assessment of clinical and chest imaging findings by an expert central review committee. Treatment details for patients who experienced a relapse of ILD were also analyzed. Of the 238 patients identified as having nivolumab‐induced ILD, 37 patients died of ILD. Corticosteroids were used in 207 (87.0%) patients. Of those, 172 (83.1%) patients responded well and survived and 35 (16.9%) died (most died during corticosteroid treatment). A total of nine patients experienced a relapse; at the time of relapse, four patients were taking nivolumab. Of those who were receiving corticosteroids at the time of relapse, three of four patients were taking low doses or had nearly completed dose tapering. All patients (except one, whose treatment was unknown) received corticosteroids for the treatment of relapse, but one patient died. Patients with NSCLC who experience nivolumab‐induced ILD are treated effectively with corticosteroids, and providing extra care when ceasing or reducing the corticosteroid dose may prevent relapse of ILD.

Abstract PS2-32: Incidental malignant findings on pre-admission chest computed tomography scan for coronavirus disease screening in patients with breast cancer or other cancers

Background: Amidst the coronavirus disease (COVID-19) pandemic, pre-admission chest computed tomography (CT) screening has been performed for all patients (pts) scheduled for cancer surgery to prevent the nosocomial spread of COVID-19 at our cancer center in Tokyo. This strategy was employed owing to a shortage of polymerase chain reaction assay opportunities and the relatively abundant availability of CT scanning in Japan. Notably, a screening CT may reveal incidental findings that are different from the original purpose of the examination. Thus far, there are no reports of incidental malignant findings on CT scans for COVID-19 screening. Methods: This single-institutional retrospective study included pts scheduled for surgery and who underwent pre-admission CT scans for COVID-19 screening between April 26, 2020, and June 12, 2020. Clinical and radiological data of pts were extracted from medical records. Clinical data included age, sex, medical history, and treatment. All CT scans for COVID-19 screening were examined one or two days before surgery and interpreted by two trained radiologists. This study aimed to reveal the ratio of incidental findings related to malignancy. Results: Between April 26, 2020, and June 12, 2020, 863 pts underwent pre-admission CT scans for COVID-19 screening. Median patient age was 58 years (range, 11-91 years), and 511 (59%) of the pts were female. The most common disease was breast cancer (n = 165, 19%), followed by colorectal cancer (n = 108, 13%), gynecological cancer (n = 107, 12%), and other cancers (n = 483, 56%). CT scan revealed radiological findings of pneumonia in 23 pts (2.7%); therefore, surgery was postponed for these pts. Incidental findings were detected in 28 pts (3.2%), including one pneumothorax and 27 findings related to malignancies. The present study included 165 pts (19%) with breast cancer and who were scheduled for curative surgery. Among them, incidental findings related to malignancies were detected in nine pts (5.5%), including small ground-glass pulmonary nodules (GGN) (n=5), pancreatic duct dilatation (n=1), suspected vertebral metastasis (n=2) and suspected liver tumor (n=1). All pts did not undergo breast surgery but underwent additional examinations after surgery. Five pts (2.5%) with GGN needed follow-up. One patient’s pancreatic duct dilatation was diagnosed as benign using ultrasound. One patient with suspected vertebral metastasis was diagnosed with degenerative changes. The other patient was diagnosed with multiple bone metastases by bone scintigraphy, and further treatment was planned. Pre-admission screening CT scan for pts with other cancers was performed in 698 pts (81%). Among them, findings related to malignancies were detected in 18 pts (2.6%), including breast nodules (n=3), lung nodules (n=5), liver metastasis (n=1), progression of metastasis (n=3), mediastinum tumor (n=1), and GGN (n=5). Two of the three pts with breast nodules were diagnosed with invasive breast cancer and planned for breast surgery after the current cancer treatment. Two pts developed new lung metastasis, and the surgical strategy was changed. The progression of known liver or lung metastasis was detected in three pts, which led to the addition of systemic chemotherapy without modification of surgical treatment. One patient had a mediastinum tumor, and an MRI evaluation after surgery revealed an athymic cyst. Five pts were determined to have GGN, and follow-up was required. Conclusion: The proportion of pts for whom pre-admission CT for COVID-19 revealed incidental findings was 3.2%. Incidental breast cancer was found in 0.4% of female pts. GGNs needed follow-up examination in 2.5% of operable breast cancer pts. Physicians and surgeons should be aware of incidental malignant findings in the COVID-19 screening CT scan.

Citation Format: Jun Masuda, Akemi Kataoka, Katsunori Oikado, Natsue Uehiro, Yukinori Ozaki, Lina Inagaki, Chieko Kato, Hidemoto Morizono, Toshimi Takano, Takayuki Ueno, Shinji Ohno. Incidental malignant findings on pre-admission chest computed tomography scan for coronavirus disease screening in patients with breast cancer or other cancers [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS2-32.

Utility of Maximum CT Value in Predicting the Invasiveness of Pure Ground-Glass Nodules

PURPOSE

To predict the histologic invasiveness of pure GGNs using the maximum CT value.

PATIENTS AND METHODS

One hundred eighty patients underwent a resection of pure GGNs. On preoperative CT imaging studies, we selected the axial section that showed the densest component of each GGN. The CT value was measured using a DICOM (Digital Imaging and Communication in Medicine) viewer, excluding portions of vessels and bronchi. The correlation between the CT value and GGN histologic diagnosis was analyzed.

RESULTS

The numbers of patients with atypical adenomatous hyperplasia, adenocarcinoma-in-situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAC) were 9, 108, 56, and 7, respectively. One of the IAC tumors exhibited lymphatic invasion, and there were no cases of vascular invasion. In comparison to preinvasive lesions (atypical adenomatous hyperplasia and AIS), invasive lesions (MIA and IAC) were correlated with a higher maximum CT value (-404 ± 113 Hounsfield units [HU] vs. -216 ± 125 HU, P < .01). The cutoff point of maximum CT value was determined at -300 HU using receiver operating characteristic curve analysis, and exhibited sensitivity and specificity of 83% and 88%, respectively. Multivariate analysis revealed that maximum CT value was an independent predictor of histologic invasiveness (odds ratio 39, P < .01). The interobserver reliability was satisfactory (intraclass correlation coefficient, 0.738; unweighted kappa-values, 0.722).

CONCLUSION

IAC and MIA accounted for 4% and 31% of the pure GGN lesions, respectively. Higher maximum CT value (≥ -300 HU) was a useful predictor of histologic invasiveness.

Radiologic features of pneumonitis associated with nivolumab in non-small-cell lung cancer and malignant melanoma

Aim: To assess the clinical features/imaging characteristics of pneumonitis reported during nationwide nivolumab postmarketing surveillance in Japan. Patients & methods: Clinical and radiological data were collected from pneumonitis cases reported during/after nivolumab treatment for melanoma or non-small-cell lung cancer. The expert central review committee evaluated each case. Results: Among 144 cases analyzed, 91 (63.2%) had radiological patterns considered typical for drug-induced pneumonitis and 53 (36.8%) patients had previously unobserved patterns with one or more atypical features, including 23 cases (16.0%) with ground glass opacity confined to the area around the tumor (peritumoral infiltration). A higher proportion of patients with (vs without) peritumoral infiltration had an antitumor response to nivolumab. Conclusion: Images of nivolumab-induced pneumonitis showed previously unobserved radiological patterns.

Characterization of Computed Tomography Imaging of Rearranged During Transfection-rearranged Lung Cancer

BACKGROUND

Rearranged during transfection (RET)-rearranged non-small-cell lung cancer (NSCLC) is relatively rare and the clinical and computed tomography (CT) image characteristics of patients with an advanced disease stage have not been well documented.

PATIENTS AND METHODS

We identified patients with advanced-stage RET-rearranged NSCLC treated in the Cancer Institute Hospital, Japanese Foundation for Cancer Research, and analyzed the clinical and CT imaging characteristics.

RESULTS

In 21 patients with advanced RET-rearranged NSCLC, RET rearrangements were identified using fluorescence in situ hybridization and/or reverse transcriptase-polymerase chain reaction. The fusion partner genes were identified as KIF5B (57%), CCDC6 (19%), and unknown (24%). CT imaging showed that 12 primary lesions (92%) were peripherally located and all were solid tumors without ground-glass, air bronchograms, or cavitation. The median size of the primary lesions was 30 mm (range, 12-63 mm). Of the 18 patients with CT images before initial chemotherapy, 12 (67%) showed an absence of lymphadenopathy. Distant metastasis included 13 with pleural dissemination (72%), 10 with lung metastasis (56%), 8 with bone metastasis (44%), and 2 with brain metastasis (11%).

CONCLUSION

Advanced RET-rearranged NSCLC manifested as a relatively small and peripherally located solid primary lesion with or without small solitary lymphadenopathy. Pleural dissemination was frequently observed.

Nivolumab-induced interstitial lung disease (ILD) in Japanese patients with non-small cell lung cancer: A study on risk factors for fatal outcome

9077

Background: We investigated case reports of nivolumab-induced ILD in patients with non-small cell lung cancer to identify risk factors for poor prognosis of ILD. Methods: Among data obtained during post-marketing surveillance of nivolumab, case reports of ILD with detailed clinical course and chest imaging (CT) findings were assessed by the ILD Expert Review Committee, which consists of respiratory medicine specialists and expert chest radiologists. The imaging findings were examined and classified into those with typical or atypical patterns. Atypical patterns included shadows limited to surrounding tumors designated as “peritumoral infiltration”, relapse of radiation pneumonitis, worsening of underlying infection, and predominant shadow in diseased side. CT pattern was classified as DAD (diffuse alveolar damage) or non-DAD. Data were analyzed using a multivariate stepwise logistic regression analysis. Results: Among 160 reported cases of ILD, 140 cases were considered to be induced by nivolumab. Imaging findings showed typical patterns in 92 patients, and 23 (25.0%) died of ILD. Atypical patterns were noted in 48 patients, and 5 (10.4%) died of ILD. The following table summarizes the results of univariate and multivariate analyses of risk factors for poor prognosis of ILD. See table. DAD pattern was observed in 20, 14 (70%) among them showed fatal outcome, whereas non-DAD pattern showed it in 14/120 (11.7%). Male and pretreatment CRP level were significant risk factors for fatal outcome. Conclusions: Nivolumab-induced ILD may show some atypical pattern that was not seen in conventional chemotherapy or EGFR-TKI. Outcome of patients with atypical patterns was better than those with typical patterns. DAD pattern at CT, male, and pretreatment level of CRP were identified as risk factors of fatal outcome. [Table: see text]

Clinical and radiological features of advanced RET-rearranged lung cancer

e23104

Background: RET fusion gene was found in 1–2% of non-small cell lung cancer (NSCLC). Most of the reports published so far investigated only surgical specimens, and details of advanced tumors were unknown. This study explored the clinical and radiological characteristics of RET-rearranged lung cancers in advanced stages. Methods: Among 1,074 advanced NSCLC patients who were treated at The Cancer Institute Hospital, Tokyo, from 2012 to 2016, 14 cases (14/1,074 = 1.3%) were treated as RET- rearranged lung cancer. The cases were identified by FISH and / or by RT-PCR (FISH 3, RT-PCR 2, FISH and RT-PCR 8, unknown 1). The fusion partner genes included KIF5B (n = 10), CCDC6 (n = 1). Three were unknown. The tumor size, location, and shape/margins of the primary tumor as well as lymphadenopathy and site of metastasis were recorded based on computed tomography (CT) images taken right before the initial chemotherapy. Results: The median age of the 14 patients was 64 years (range, 34–79), with 10 patients (71%) over 60 years old. Nine patients (64%) were women, whereas 10 patients (71%) were never smokers. Eight patients were classified as stage IV and 6 underwent recurrence after surgery. We successfully evaluated CT images at the initial chemotherapy of 12 patients. Of the 7 patients whose primary lesions were detectable, all were located peripherally and were of a solid tumor type without ground-glass, air bronchograms, or cavitation. The median size of the primary lesion was 3.0 cm (range, 1.2–6.8), and 3 lesions were less than 3.0 cm. Only 5 patients had lymphadenopathy (4 were of Stage IV, 1 was a recurrence), most of which were isolated with a median size of 1.5 cm (range, 1.2–3.5). The sites of distant metastases included 8 pleural disseminations, 5 lungs, 5 bones, 3 livers, 2 brains, and 0 adrenals. Conclusions: Advanced RET-rearranged lung cancer manifested as a relatively small and peripherally located solid primary lesion with isolated lymphadenopathy. Pleural dissemination was frequently observed, whereas brain metastasis was less frequent. These features differ from EGFR-mutated or ALK-fused lung cancers.

Preexistence of CT findings with usual interstitial pneumonia (UIP) pattern correlates to radiation pneumonitis (RP) in non-small cell lung cancer (NSCLC) patients receiving chemoradiotherapy (CRT)

e20063

Background: RP is a major toxicity commonly observed in NSCLC patients who receive CRT; RP prediction is a critical issue. Although preexisting interstitial pneumonia (IP) is considered as one of the risk factors of RP, the correlation between interstitial lung shadows (ILSs) in the pretreatment CT scan and RP is not well examined. Methods: We reviewed patients with stage III NSCLC who received CRT at our hospital from January 2011 until December 2014. The pretreatment CT scans were retrospectively evaluated, and preexisting ILSs were classified according to the ATS/ERS/JRS/ALAT statement for idiopathic pulmonary fibrosis (IPF) as follows: UIP pattern, possible UIP pattern, and others (not UIP pattern). The incidence, severity, and features of RP were compared between ILS patterns. Results: In total, 105 patients with stage III NSCLC had received CRT. ILSs in pretreatment CT scans were identified in 16 (15.2%) of 105 patients. Of all the identified patterns, one (0.9%) was UIP pattern, six (5.7%) were possible UIP pattern, and nine (8.6%) were not UIP pattern. Grade 3 or higher RP was observed in 2 of 7 (28.6%) patients with UIP pattern or possible UIP pattern and 1 of 9 (11.1%) patients with not UIP pattern ( P = 0.55). RP that extended outside the irradiation field like an acute exacerbation of IP was observed in 4 of 7 (57.1%) patients with UIP pattern or possible UIP pattern and 1 of 9 (11.1%) patients with not UIP pattern ( P = 0.106). Conclusions: Preexistence of ILSs classified as UIP pattern or possible UIP pattern should be considered as a risk factor for severe or extensive RP after CRT.

Correlation of low CT attenuation and necrotic features of tumor in contrast-enhanced CT with nivolumab response

e23105

Background: Anti-PD1/PD-L1 antibodies, including nivolumab, produce durable responses in non-small cell lung cancer (NSCLC), but the response rate is about 20% in unselected NSCLC. Identifying predictive markers of response is necessary. Although PD-L1 expression may be a potential biomarker, evaluating whole tumors based on a small sample is difficult. Identifying radiographic features of responders can be very useful. We hypothesized that low attenuation on computed tomography (CT), considered to represent necrosis, correlates with nivolumab response. Methods: We retrospectively evaluated contrast-enhanced CT images before treatment and tumor response in 60 patients receiving nivolumab. The largest tumor lesion was characterized in each patient. CT attenuation (CTA) of whole tumor areas was measured; the presence of radiological findings of necrosis (necrotic features), presenting cavitation or ring- or patchy-enhancement in tumors, were assessed. We evaluated the association between CT imaging characteristics and nivolumab response and that between CT imaging characteristics and PD-L1 expression in tumors. Results: Thirty-nine target lesions in lung, 12 in lymph node, and 9 in other organs were chosen. The mean CTA was 58.5 ± 15.3 HU. Necrotic feature were observed in 24 (40%) of 60 lesions.Twenty of 60 lesions (33%) shrank to > 30% with nivolumab treatment. Mean CTA in responding lesions was 48.6 HU, significantly lower than that in nonresponding lesions (63.4 HU) (p < 0.001). The response rate of lesions with/without necrotic features was 45% and 28%, respectively (p = 0.246).Systemic tumor response, assessed by RECIST v1.1, was confirmed in 20 (33%) patients. Mean CTA of target lesions was lower in responders than patients with stable disease or progressive disease (51.4 vs. 62.0 HU, p = 0.011). The systemic response rate of lesions with/without necrotic features was 50% and 25%, respectively (p = 0.081).Mean CTA of target lesions was lower in tumors with high PD-L1 expression than in tumors with low PD-L1 expression (54.8 vs. 64.4 HU, p = 0.045). Conclusions: Low CTA and necrotic features in CT may correlate with nivolumab response. Tumors with low CTA may have high PD-L1 expression.

Comparison of sensitivity of lung nodule detection between radiologists and technologists on low-dose CT lung cancer screening images

OBJECTIVES

The objective of this study was to compare the sensitivity of detection of lung nodules on low-dose screening CT images between radiologists and technologists.

METHODS

11 radiologists and 10 technologists read the low-dose screening CT images of 78 subjects. On images with a slice thickness of 5 mm, there were 60 lung nodules that were ≥5 mm in diameter: 26 nodules with pure ground-glass opacity (GGO), 7 nodules with mixed ground-glass opacity (GGO with a solid component) and 27 solid nodules. On images with a slice thickness of 2 mm, 69 lung nodules were ≥5 mm in diameter: 35 pure GGOs, 7 mixed GGOs and 27 solid nodules. The 21 observers read screening CT images of 5-mm slice thickness at first; then, 6 months later, they read screening CT images of 2-mm slice thickness from the 78 subjects.

RESULTS

The differences in the mean sensitivities of detection of the pure GGOs, mixed GGOs and solid nodules between radiologists and technologists were not statistically significant, except for the case of solid nodules; the p-values of the differences for pure GGOs, mixed GGOs and solid nodules on the CT images with 5-mm slice thickness were 0.095, 0.461 and 0.005, respectively, and the corresponding p-values on CT images of 2-mm slice thickness were 0.971, 0.722 and 0.0037, respectively.

CONCLUSION

Well-trained technologists may contribute to the detection of pure and mixed GGOs ≥5 mm in diameter on low-dose screening CT images.

Malignant pleural mesothelioma detected by spontaneous pneumothorax

We report a middle-aged man, without occupational or environmental exposure to asbestos, who presented with spontaneous pneumothorax. Computed tomography showed a 13-mm right apical mass. He underwent tumorectomy and was diagnosed with malignant pleural mesothelioma. A local recurrence with multiple and diffuse pleural involvement later appeared. The patient eventually underwent panpleuropneumonectomy, recovered well, and has been doing well for 18 months.