Development of Macrolide Resistance and Reinfection in Refractory Mycobacterium avium Complex Lung Disease

RATIONALE

Patients with refractory Mycobacterium avium complex lung disease (MAC-LD) undergo long-term macrolide therapy, but macrolide resistance develops infrequently.

OBJECTIVES

The aim of this study was to determine whether reinfection was a factor in the low incidence of macrolide resistance in patients with refractory MAC-LD.

METHODS

Among 481 patients with treatment-naive MAC-LD who started antibiotic treatment between January 2002 and December 2013, we identified 72 patients with refractory disease, characterized by persistently positive sputum cultures despite ≥12 months of treatment. Molecular analyses of the 23S ribosomal RNA gene responsible for macrolide resistance and serial mycobacterial genotyping were performed using stored MAC isolates.

MEASUREMENTS AND MAIN RESULTS

The median duration of treatment was 32 months (interquartile range, 24-41 mo) in 72 patients. After treatment for a median of 33 months (interquartile range, 21-44 mo), macrolide resistance developed in 16 (22%) patients. Molecular analysis of isolates from 15 patients revealed that 80% (12 of 15) had a point mutation at position 2,058 or 2,059 of the 23S ribosomal RNA gene. Of the 49 patients who had stored pre- and post-treatment isolates, mycobacterial genotyping revealed that reinfection by new MAC strains occurred in 36 (73%) patients. New MAC strains were found in 24 (49%) patients, and mixed infections with original and new strains occurred in 12 (24%) patients. Only 13 (27%) patients had persistent infections with their original MAC strains.

CONCLUSIONS

Refractory MAC-LD is commonly caused by reinfection with new strains rather than persistence of the original strain, which may explain the infrequent development of macrolide resistance in refractory MAC-LD. Clinical trial registered with www.clinicaltrials.gov (NCT00970801).

Risk factors and clinical characteristics of lung cancer in idiopathic pulmonary fibrosis: a retrospective cohort study

Background

Lung cancer is a common comorbidity of idiopathic pulmonary fibrosis (IPF) and has poor outcomes. The incidence and clinical factors related to development of lung cancer in idiopathic pulmonary fibrosis (IPF) are unclear. The aim of this study was to elucidate the cumulative incidence, risk factors, and clinical characteristics of lung cancer in IPF.

Methods

In this retrospective study, we analyzed clinical data for 938 patients who were diagnosed with IPF without lung cancer between 1998 and 2013. Demographic, physiologic, radiographic, and histologic characteristics were reviewed. Cumulative incidence of lung cancer and survival were estimated by the Kaplan-Meier method. Risk factors of lung cancer development were determined by Cox proportional hazard analysis.

Results

Among 938 IPF patients without lung cancer at initial diagnosis, lung cancer developed in 135 (14.5%) during the follow-up period. The cumulative incidences of lung cancer were 1.1% at 1 year, 8.7% at 3, 15.9% at 5, and 31.1% at 10 years. Risk factors of lung cancer were male gender, current smoking at IPF diagnosis, and rapid annual decline of 10% or more in forced vital capacity (FVC). Patients who developed lung cancer were mostly elderly men with smoking history. Squamous cell carcinoma followed by adenocarcinoma was the most common histologic type. Lung cancer was frequently located in areas abutting or within fibrosis. Survival was significantly worse in patients with lung cancer compared to patients with IPF alone.

Conclusion

Lung cancer frequently developed in patients with IPF and was common in current-smoking men with rapid decline of FVC.

Electronic supplementary material

The online version of this article (10.1186/s12890-019-0905-8) contains supplementary material, which is available to authorized users.

Evaluating the tumor biology of lung adenocarcinoma: A multimodal analysis

We evaluated the relationships among functional imaging modality such as PET-CT and DW-MRI and lung adenocarcinoma pathologic heterogeneity, extent of invasion depth, and tumor cellularity as a marker of tumor microenvironment.In total, 74 lung adenocarcinomas were prospectively included. All patients underwent 18F-fluorodeoxyglucose (FDG) PET-CT and MRI before curative surgery. Pathology revealed 68 stage I tumors, 3 stage II tumors, and 3 stage IIIA tumors. Comprehensive histologic subtyping was performed for all surgically resected tumors. Maximum standardized uptake value (SUVmax) and ADC values were correlated with pathologic grade, extent of invasion, solid tumor size, and tumor cellularity.Mean solid tumor size (low: 1.7 ± 3.0 mm, indeterminate: 13.9 ± 14.2 mm, and high grade: 30.3 ± 13.5 mm) and SUVmax (low: 1.5 ± 0.2, indeterminate: 3.5 ± 2.5, and high grade: 15.3 ± 0) had a significant relationship with pathologic grade based on 95% confidence intervals (P = .01 and P < .01, respectively). SUVmax showed a strong correlation with tumor cellularity (R = 0.713, P < .001), but was not correlated with extent of invasion (R = 0.387, P = .148). A significant and strong positive correlation was observed among SUVmax values and higher cellularity and pathologic grade. ADC did not exhibit a significant relationship with tumor cellularity.Intratumor heterogeneity quantification using a multimodal-multiparametric approach might be effective when tumor volume consists of a real tumor component as well as a non-tumorous stromal component.

Diagnostic Performance of Radial Probe Endobronchial Ultrasound without a Guide-Sheath and the Feasibility of Molecular Analysis

BACKGROUND

Radial probe endobronchial ultrasound (R-EBUS), is effective for tissue diagnosis of lung lesions. We evaluated the diagnostic performance of R-EBUS both a guide-sheath and fluoroscopy and identified factors associated with accurate diagnosis. The feasibility of molecular and genetic testing, using specimens obtained by R-EBUS, was also investigated.

METHODS

The study retrospectively reviewed 211 patients undergoing R-EBUS without a guide-sheath and fluoroscopy, June 2016-May 2017. After excluding 27 patients of which the target lesion was not reached, 184 were finally included. Multivariate logistic regression was used, to identify factors associated with accurate diagnosis.

RESULTS

Among 184 patients, R-EBUS-guided biopsy diagnosed malignancy in 109 patients (59%). The remaining 75 patients (41%) with non-malignant results underwent additional work-ups, and 34 were diagnosed with malignancy. Based on final diagnosis, diagnostic accuracy was 80% (136/170), and sensitivity and specificity for malignancy were 76% (109/143) and 100% (27/27), respectively. In multivariate analysis, peripheral location (adjusted odds ratio [aOR], 3.925; 95% confidence interval [CI], 1.203-12.811; p=0.023), and central position of the probe (aOR, 2.435; 95% CI, 1.424-7.013; p=0.035), were associated with accurate diagnosis of malignancy. Molecular and genetic analyses were successful, in all but one case, with inadequate specimens.

CONCLUSION

R-EBUS-guided biopsy without equipment, is effective for tissue diagnosis. Peripheral location and central position of the radial probe, were crucial for accurate diagnosis. Performance of molecular and genetic testing, using samples obtained by R-EBUS, was satisfactory.

The use of surgery in a real-world clinic to diagnose and treat pulmonary cryptococcosis in immunocompetent patients

Background

We evaluated the role played by surgery in the diagnosis and treatment of pulmonary cryptococcosis (PC) in immunocompetent subjects.

Methods

We retrospectively studied 53 immunocompetent patients who were pathologically diagnosed with PC between January 2000 and December 2016 in a tertiary referral center. We compared the radiological presentations of, and diagnostic modalities used to evaluate, patients diagnosed both surgically and non-surgically. We also compared the treatment outcomes of patients who underwent surgical resection alone and those who received additional antifungals following surgical resection.

Results

Of the 53 patients, 30 (57%) were diagnosed via non-surgical modalities including percutaneous needle biopsy (PCNB) (n=29) and transbronchial lung biopsy (TBLB) (n=1); and 23 (43%) were diagnosed by surgical modalities including video-assisted thoracoscopic wedge resection (n=22) and lobectomy (n=1). An initial clinical suspicion of a lung malignancy was associated with the use of surgical diagnostic approaches (P<0.001). Whereas undetermined locations were associated with the use of surgical diagnostic approaches, radiological findings such as clustered nodular patterns (P<0.001), cavities (P=0.005), air bronchograms (P<0.001), and peripheral lesions (P<0.001) were associated with the use of non-surgical diagnostic approaches. Of the 30 non-surgically diagnosed patients, 21 (70%) were treated with antifungals and 9 (30%) were followed-up without treatment. Of the 23 patients who underwent surgical treatment, 8 received additional antifungals. The proportion of patients who had radiological improvement was significantly higher in surgically diagnosed patients than non-surgically diagnosed patients (100% vs. 73%; P=0.007). However, there was no significant difference in disease progression between patients who underwent surgical resection alone and those who additionally received antifungals (P=0.999).

Conclusions

Surgical resection was required in some patients to diagnose PC. An initial suspicion of a lung malignancy was associated with use of surgical diagnostic approaches. Surgical resection not only afforded reliable diagnoses but also effectively treated PC. There was no need for additional antifungals after complete surgical resection.

Clinical usefulness of routine AFB culture and MTB PCR of EBUS-TBNA needle rinse fluid

BACKGROUND AND OBJECTIVE

We evaluated the usefulness of acid-fast bacilli (AFB) culture and Mycobacterium tuberculosis (MTB) polymerase chain reaction (PCR) of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) needle rinse fluid for diagnosing tuberculous lymphadenitis.

METHODS

EBUS-TBNA needle rinse fluid was routinely used for AFB culture and MTB PCR. The patients were categorized according to the pre-procedural diagnosis (Group A, suspected/histology-confirmed lung cancer; Group B, extrapulmonary malignancy; and Group C, other benign diseases).

RESULTS

Of the 4672 subjects, 104 (2.2%) were diagnosed with tuberculous lymphadenitis; 1.0%, 4.6% and 12.7% of Group A, B and C, respectively. Tuberculous lymphadenitis was diagnosed in 0.2%, 1.0% and 4.5% Group A, B and C patients, respectively, by histopathology. On addition of AFB culture to histopathology, tuberculous lymphadenitis was diagnosed in 1.0%, 4.4% and 10.3% of Group A, B and C patients, respectively (P < 0.001, P = 0.001 and P = 0.005, respectively). On addition of MTB PCR to histopathology, tuberculous lymphadenitis was diagnosed in 0.4%, 1.9% and 8.8%, respectively (Group C; P = 0.029).

CONCLUSION

Routine AFB culture of needle rinse fluid was useful to increase the diagnostic yield of tuberculous lymphadenitis for all subjects who underwent EBUS-TBNA regardless of pre-procedural diagnosis in an intermediate tuberculosis (TB)-burden country. However, MTB PCR was only useful in subjects with pre-procedural diagnosis of benign pulmonary diseases.

Treatment with a macrolide-containing regimen for Mycobacterium kansasii pulmonary disease

BACKGROUND

Mycobacterium kansasii is a major pathogen associated with nontuberculous mycobacterial pulmonary disease. For treatment of M. kansasii pulmonary disease, daily therapy with isoniazid, rifampin, and ethambutol is traditionally recommended. Although a regimen containing a macrolide, instead of isoniazid, has been recently recommended, supporting data are limited. We compared the treatment outcomes of a macrolide-containing regimen (macrolide group) and an isoniazid-containing regimen (isoniazid group) on patients with M. kansasii pulmonary disease.

METHODS

A total of 49 patients were identified between January 2002 and December 2016. Treatment outcomes for the isoniazid group (n = 24) and the macrolide group (n = 25) were compared.

RESULTS

Baseline characteristics of the isoniazid and macrolide groups were similar. Favorable outcomes did not differ between the isoniazid group (79%, n = 19) and macrolide group (88%, n = 22, P = 0.463). Total treatment duration (median 17.9 months vs. 15.4 months; P = 0.712) and time to culture conversion (median 2.0 months vs. 1.2 months; P = 0.838) were also similar between the isoniazid and macrolide groups. Five patients who completed three-times-weekly intermittent treatment containing a macrolide for non-cavitary M. kansasii pulmonary disease achieved negative sputum culture conversion within 12 months of treatment. Only one patient experienced recurrence of M. kansasii pulmonary disease in the isoniazid group.

CONCLUSIONS

A macrolide-containing regimen appears to be as effective as an isoniazid-containing regimen for treatment of M. kansasii pulmonary disease. Additionally, intermittent therapy containing a macrolide could be an alternative treatment option for non-cavitary M. kansasii pulmonary disease.

Incidence of brain metastasis in lung adenocarcinoma at initial diagnosis on the basis of stage and genetic alterations

OBJECTIVE

Patients with lung adenocarcinoma (ADC) are at higher risk of the development of brain metastasis (BM), and genetic alterations are associated with BM.

PATIENTS AND METHODS

A total of 598 patients with lung ADC in our institution between January 2014 and December 2014 were reviewed retrospectively. We evaluated the incidence of BM by stage and genetic alterations.

RESULTS

Of the 598 patients, 97 (16.2%) had BM, which occurred across all stages. The incidence of BM showed a tendency to increase as the stage increased (p < 0.001, trend test). Although patients with EGFR mutations had BM across all stages, those with ALK or K- mutations had BM only in stage III and IV diseases. Regardless of types of mutations, the incidence of BM showed a tendency to increase as the T or N staging increased (p < 0.001 for each of EGFR, ALK, and K-RAS mutations, trend test). Whereas BM incidence showed a tendency to increase as the M staging increased in patients with EGFR-mutant lung ADC (p < 0.001, trend test), there was no linear trend between M staging and ALK (p = 0.469, trend test) or K-RAS mutations (p = 0.066, trend test). After adjusting covariables, EGFR mutations were associated with BM in never-smokers (adjusted OR = 2.07, 95% CI = 1.02-4.34) and K-RAS mutations were risk factors for BM in males (adjusted OR = 3.86, 95% CI = 1.01-14.43).

CONCLUSIONS

BM occurred in approximately 16% of lung ADC patients, including 3% with stage I diseases. Whereas EGFR-mutant lung ADC had BM across all stages, ALK- or K-RAS-mutant lung ADC had BM only in advanced stages. EGFR mutations were risk factors for BM among never-smokers and K-RAS mutations were risk factors among males.

Genetic mutations in linezolid-resistant Mycobacterium avium complex and Mycobacterium abscessus clinical isolates

There are no studies evaluating the mechanisms driving linezolid resistance in nontuberculous mycobacteria. The novel mutations G2599A and A2137T in the 23S rRNA gene and mutations A439G and G443A in the rplD gene associated with linezolid resistance were identified in linezolid-resistant M. avium complex isolates.

Safety of endobronchial ultrasound-guided transbronchial needle aspiration in patients with lung cancer within a year after percutaneous coronary intervention

Background

Endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) may be necessary for patients with incidental lung cancer during or after coronary intervention. Although EBUS‐TBNA is quite safe, the safety in patients who recently received percutaneous coronary intervention (PCI) has not been demonstrated. The aim of this study was to assess the safety of EBUS‐TBNA in patients with lung cancer who underwent PCI within one year.

Methods

We retrospectively reviewed the medical records of 24 patients who underwent EBUS‐TBNA within one year after PCI between May 2009 and June 2017. Cardiovascular complications (death, myocardial infarction, arrhythmia, and acute heart failure) were assessed as primary outcomes. Procedural‐related complications were assessed as secondary outcomes.

Results

The coronary artery diseases requiring PCI were: myocardial infarction (n = 10), unstable angina (n = 10), stable angina (n = 2), and silent ischemia (n = 2). The median interval between PCI and EBUS‐TBNA was 125 days (interquartile range: 66–180). Atrial fibrillation with a rapid ventricular response temporarily occurred in one patient after EBUS‐TBNA. No other significant cardiovascular complications were encountered. Fifteen patients were administered an anti‐thrombotic agent the day of EBUS‐TBNA, while four had ceased taking the agent < 4 days before EBUS‐TBNA, however, there was no significant bleeding among those patients.

Conclusion

EBUS‐TBNA was safe and did not cause serious adverse events in patients with lung cancer who required tissue confirmation or mediastinal staging within one year after PCI. Incidental lung cancer found during or after a coronary intervention should be actively evaluated by EBUS‐TBNA.

Drug susceptibility patterns of Mycobacterium abscessus and Mycobacterium massiliense isolated from respiratory specimens

In this study, we aimed to retrospectively investigate and compare the drug susceptibility patterns of two major Mycobacterium abscessus complex (MABC) species; M. abscessus and M. massiliense. A total of 546 MABC respiratory isolates (277 M. abscessus and 269 M. massiliense) from 2011 to 2016 were analyzed in this study. We estimated minimum inhibitory concentrations (MICs) using the broth microdilution method, and we calculated MIC₅₀ and MIC₉₀ values from the MIC distribution. Both M. abscessus and M. massiliense were highly susceptible to amikacin and linezolid. For M. abscessus, the proportions of inducible and acquired resistance to clarithromycin were 68.6% and 12.3%, respectively. Only 15.2% of M. abscessus remained susceptible at day 14. On the other hand, none of the M. massiliense showed inducible resistance and 6.3% showed acquired resistance to clarithromycin. A total of 92.6% of the M. massiliense remained susceptible at day 14. The resistance rate of M. abscessus to moxifloxacin (90.3%) was significantly higher than that of M. massiliense (83.3%; p = 0.016). These susceptibility differences may explain the divergent treatment outcomes between patients with pulmonary disease caused by these two species.

Comparison of four models predicting the malignancy of pulmonary nodules: A single-center study of Korean adults

Objective

Four commonly used clinical models for predicting the probability of malignancy in pulmonary nodules were compared. While three of the models (Mayo Clinic, Veterans Association [VA], and Brock University) are based on clinical and computed tomography (CT) characteristics, one model (Herder) additionally includes the ¹⁸F-fluorodeoxyglucose (FDG) uptake value among the positron emission tomography (PET) characteristics. This study aimed to compare the predictive power of these four models in the context of a population drawn from a single center in an endemic area for tuberculosis in Korea.

Methods

A retrospective analysis of 242 pathologically confirmed nodules (4–30 mm in diameter) in 242 patients from January 2015 to December 2015 was performed. The area under the receiver operating characteristic curve (AUC) was used to assess the predictive performance with respect to malignancy.

Results

Of 242 nodules, 187 (77.2%) were malignant and 55 (22.8%) were benign, with tuberculosis granuloma being the most common type of benign nodule (23/55). PET was performed for 227 nodules (93.8%). The Mayo, VA, and Brock models showed similar predictive performance for malignant nodules (AUC: 0.6145, 0.6042 and 0.6820, respectively). The performance of the Herder model (AUC: 0.5567) was not significantly different from that of the Mayo (vs. Herder, p = 0.576) or VA models (vs. Herder, p = 0.999), and there were no differences among the three models in determining the probability of malignancy of pulmonary nodules. However, compared with the Brock model, the Herder model showed a significantly lower ability to predict malignancy (adjusted p = 0.0132).

Conclusions

In our study, the Herder model including the ¹⁸FDG uptake value did not perform better than the other models in predicting malignant nodules, suggesting the limited utility of adding PET/CT data to models predicting malignancy in populations within endemic areas for benign inflammatory nodules, such as tuberculosis.

Anaplastic lymphoma kinase rearrangement in surgically resected stage IA lung adenocarcinoma

Background

It has not been determined if adjuvant chemotherapy would be helpful for completely resected early-stage lung adenocarcinoma even with unfavorable genetic markers. As the positive anaplastic lymphoma kinase (ALK) rearrangement is associated with aggressive clinical feature in lung adenocarcinoma, we evaluated the treatment outcomes of completely resected stage IA lung adenocarcinoma according to initial ALK status.

Methods

This is a retrospective cohort study including 309 patients with surgically resected stage IA lung adenocarcinoma from February 2010 to December 2013. Patients were screened for ALK rearrangement using immunohistochemistry. A positive ALK status was defined as an immunohistochemistry score of 2+ or more. Both disease-free survival (DFS) and the initial recurrence pattern were analyzed according to ALK status.

Results

Twenty-three (7.4%) patients had ALK-positive adenocarcinoma. During the median follow-up of 35.8 months, recurrence developed in 34 (11.0%) patients. The patients with ALK-positive tumor had significantly lower 5-year DFS rate (62.4%) compared to those with ALK-negative tumor (86.5%; P=0.038). The multivariable analysis showed that ALK rearrangement was associated with a higher risk of disease recurrence (adjusted hazard ratio =2.64; 95% confidence interval, 1.08-6.44). In addition, patient with ALK-positive tumor showed more frequent recurrence in regional lymph nodes compared with those with ALK-negative tumor (83.3% vs. 28.6%; P=0.031).

Conclusions

In patients with completely resected stage IA lung adenocarcinoma, ALK rearrangement was associated with unfavorable DFS and more frequent regional lymph node metastasis. Therefore, careful surveillance for recurrence should be performed in this subset of patients.

Genomic alterations of ground-glass nodular lung adenocarcinoma

In-depth molecular pathogenesis of ground-glass nodular lung adenocarcinoma has not been well understood. The objectives of this study were to identify genomic alterations in ground-glass nodular lung adenocarcinomas and to investigate whether viral transcripts were detected in these tumors. Nine patients with pure (n = 4) and part-solid (n = 5) ground-glass nodular adenocarcinomas were included. Six were females with a median age of 58 years. We performed targeted exon sequencing and RNA sequencing. EGFR (n = 10), IDH2 (n = 2), TP53 (n = 1), PTEN (n = 1), EPHB4 (n = 1), and BRAF (n = 1) were identified as driver mutations by targeted exon sequencing. Vasculogenesis-associated genes including NOTCH4 and TGFBR3 expression were significantly downregulated in adenocarcinoma tissue versus normal tissue (adjusted P values < 0.001 for both NOTCH4 and TGFBR3). In addition, five novel fusion gene loci were identified in four lung adenocarcinomas. However, no significant virus-associated transcripts were detected in tumors. In conclusions, EGFR, IDH2, TP53, PTEN, EPHB4, and BRAF were identified as putative driver mutations of ground-glass nodular adenocarcinomas. Five novel fusion genes were also identified in four tumors. Viruses do not appear to be involved in the tumorigenesis of ground-glass nodular lung adenocarcinoma.

Treatment outcomes of rifabutin-containing regimens for rifabutin-sensitive multidrug-resistant pulmonary tuberculosis

OBJECTIVES

The aim of this study was to evaluate whether rifabutin can improve treatment outcomes in patients with rifabutin-sensitive MDR-TB.

METHODS

A retrospective cohort study was performed on 76 patients with rifabutin-sensitive MDR-TB who were treated with or without rifabutin between 2006 and 2011.

RESULTS

Overall, 75% (57/76) of patients achieved favorable outcomes, including cure (53/76, 70%) and treatment completion (4/76, 5%). In contrast, 25% (19/76) had unfavorable treatment outcomes, which included treatment failure (6/76, 8%), death (2/76, 3%), loss to follow-up (4/76. 5%), and no evaluation due to transfer to other institutions (7/76, 9%). Rifabutin was given to 52 (68%) of the 76 patients with rifabutin-sensitive MDR-TB. Although favorable treatment outcomes were more frequent in patients who received rifabutin [81% (42/52)] than in those who did not receive rifabutin [63% (15/24)], this difference was not statistically significant (P=0.154). However, in multivariable regression logistic analysis, use of rifabutin was significantly associated with favorable treatment outcomes in patients with rifabutin-sensitive MDR-TB (adjusted odds ratio=9.80, 95% confidence interval=1.65-58.37, P=0.012).

CONCLUSIONS

These results suggest that the use of rifabutin can improve treatment outcomes in patients with rifabutin-sensitive MDR-TB.

Pathologic stratification of operable lung adenocarcinoma using radiomics features extracted from dual energy CT images

PURPOSE

To evaluate the usefulness of surrogate biomarkers as predictors of histopathologic tumor grade and aggressiveness using radiomics data from dual-energy computed tomography (DECT), with the ultimate goal of accomplishing stratification of early-stage lung adenocarcinoma for optimal treatment.

RESULTS

Pathologic grade was divided into grades 1, 2, and 3. Multinomial logistic regression analysis revealed i-uniformity and 97.5th percentile CT attenuation value as independent significant factors to stratify grade 2 or 3 from grade 1. The AUC value calculated from leave-one-out cross-validation procedure for discriminating grades 1, 2, and 3 was 0.9307 (95% CI: 0.8514-1), 0.8610 (95% CI: 0.7547-0.9672), and 0.8394 (95% CI: 0.7045-0.9743), respectively.

MATERIALS AND METHODS

A total of 80 patients with 91 clinically and radiologically suspected stage I or II lung adenocarcinoma were prospectively enrolled. All patients underwent DECT and F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT, followed by surgery. Quantitative CT and PET imaging characteristics were evaluated using a radiomics approach. Significant features for a tumor aggressiveness prediction model were extracted and used to calculate diagnostic performance for predicting all pathologic grades.

CONCLUSIONS

Quantitative radiomics values from DECT imaging metrics can help predict pathologic aggressiveness of lung adenocarcinoma.

Changing Epidemiology of Nontuberculous Mycobacterial Lung Diseases in a Tertiary Referral Hospital in Korea between 2001 and 2015

This study investigated the changes in the major etiologic organisms and clinical phenotypes of nontuberculous mycobacterial lung disease (NTM-LD) over a recent 15-year period in Korea. The increase of number of patients with NTM-LD was primarily due to an increase of Mycobacterium avium complex (MAC) lung disease (LD). Among MAC cases, the proportion of M. avium increased compared with M. intracellulare, whereas the incidence of M. abscessus complex and M. kansasii LD remained relatively stable. The proportion of cases of the nodular bronchiectatic form increased compared with the fibrocavitary form of NTM-LD.

Treatment outcomes of macrolide-susceptible Mycobacterium abscessus lung disease

Mycobacterium abscessus lung disease is difficult to treat due to inducible resistance to macrolides. However, 15%-20% of isolates are macrolide susceptible. In 14 patients with macrolide-susceptible M. abscessus lung disease, all isolates had nonfunctional erm(41) gene, and sputum culture conversion rate was achieved in 93% (13/14) following antibiotic therapy.

Are There Any Additional Benefits to Performing Positron Emission Tomography/Computed Tomography Scans and Brain Magnetic Resonance Imaging on Patients with Ground-Glass Nodules Prior to Surgery?

Background

A ground-glass nodule (GGN) represents early-stage lung adenocarcinoma. However, there is still no consensus for preoperative staging of GGNs. Therefore, we evaluated the need for the routine use of positron emission tomography/computed tomography (PET)/computed tomography (CT) scans and brain magnetic resonance imaging (MRI) during staging.

Methods

A retrospective analysis was undertaken in 72 patients with 74 GGNs of less than 3 cm in diameter, which were confirmed via surgery as malignancy, at the Samsung Medical Center between May 2010 and December 2011.

Results

The median age of the patients was 59 years. The median GGN diameter was 18 mm. Pure and part-solid GGNs were identified in 35 (47.3%) and 39 (52.7%) cases, respectively. No mediastinal or distant metastasis was observed in these patients. In preoperative staging, all of the 74 GGNs were categorized as stage IA via chest CT scans. Additional PET/CT scans and brain MRIs classified 71 GGNs as stage IA, one as stage IIIA, and two as stage IV. However, surgery and additional diagnostic work-ups for abnormal findings from PET/CT scans classified 70 GGNs as stage IA, three as stage IB, and one as stage IIA. The chest CT scans did not differ from the combined modality of PET/CT scans and brain MRIs for the determination of the overall stage (94.6% vs. 90.5%; kappa value, 0.712).

Conclusion

PET/CT scans in combination with brain MRIs have no additional benefit for the staging of patients with GGN lung adenocarcinoma before surgery.

Treatment outcomes in patients with extranodal marginal zone B-cell lymphoma of the lung

OBJECTIVES

To evaluate clinical presentations, treatment modalities, and outcomes of pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma by stage strata.

METHODS

We retrospectively reviewed 51 patients diagnosed with pulmonary MALT lymphoma between January 2003 and December 2015. To compare treatment modalities and outcomes, we stratified the patients into low-stage (IE/IIE) and high-stage (IIIE/IVE) groups using modified Ann Arbor staging. Progression-free survival was estimated using Kaplan-Meier curves, and differences were compared using the log-rank test. A hazard ratio of progression by stage strata, adjusted for other clinical variables, was determined using a Cox adjusted proportional hazards model.

RESULTS

The majority of patients had stage IE disease (76.5%; 39 of 51). With advancing stage, patients were more likely to have respiratory and B symptoms and higher International Prognostic Index scores. The most common treatment modality was surgical resection in low-stage patients (33 of 43) and chemotherapy in high-stage patients (7 of 8). At a median follow-up of 40.7 months, progression-free survival was longer for low-stage patients (median, 40.7 months vs 24.9 months; P < .001), and high-stage patients were 9.2 times more likely to progress (hazard ratio, 9.24; 95% confidence interval, 1.93-44.36). Among 30 patients with surgically resected stage IE disease, 8 with central lesions were treated via lobectomy and 22 with peripheral lesions were treated via lobectomy (n = 8) or limited resection (n = 14). One of these patients, with a central lesion, experienced disease recurrence.

CONCLUSIONS

Our findings suggest that the clinical course of low-stage pulmonary MALT lymphoma, for which the mainstay of treatment is surgical resection, might be indolent.

Mycobacterial Characteristics and Treatment Outcomes in Mycobacterium abscessus Lung Disease

Background

Treatment outcomes of patients with Mycobacterium abscessus subspecies abscessus lung disease are poor, and the microbial characteristics associated with treatment outcomes have not been studied systematically. The purpose of this study was to identify associations between microbial characteristics and treatment outcomes in patients with M. abscessus lung disease.

Methods

Sixty-seven consecutive patients with M. abscessus lung disease undergoing antibiotic treatment for ≥12 months between January 2002 and December 2012 were included. Morphotypic and genetic analyses were performed on isolates from 44 patients.

Results

Final sputum conversion to culture negative occurred in 34 (51%) patients. Compared to isolates from 24 patients with persistently positive cultures, pretreatment isolates from 20 patients with final negative conversion were more likely to exhibit smooth colonies (9/20, 45% vs 2/24, 8%; P = .020), susceptibility to clarithromycin (7/20, 35% vs 1/24, 4%; P = .015), and be of the C28 sequevar with regard to the erm(41) gene (6/20, 30% vs 1/24, 4%; P = .035). Mycobacterium abscessus lung disease recurred in 5 (15%) patients after successful completion of antibiotic therapy. Genotypic analysis revealed that most episodes (22/24, 92%) of persistently positive cultures during antibiotic treatment and all cases of microbiologic recurrence after treatment completion were caused by different M. abscessus genotypes within a patient.

Conclusions

Precise identification to the subspecies level and analysis of mycobacterial characteristics could help predict treatment outcomes in patients with M. abscessus lung disease. Treatment failures and recurrences are frequently associated with multiple genotypes, suggesting reinfection.

Clinical Trials Registration

NCT00970801.