Homologous Recombination Repair Gene Alterations Are Associated with Tumor Mutational Burden and Survival of Immunotherapy.

BACKGROUND: Comprehensive genomic profiling (CGP) has become generally accepted practice in cancer care since CGP has become reimbursed by national healthcare insurance in Japan in 2019. However, its usefulness for cancer patients is insufficient for several reasons. METHODS: In an observational clinical study of FoundationOne® CDx, potential biomarkers were explored and the cause of testing failure was investigated. A total of 220 cancer patients were enrolled in the study during the period from 2018 to 2019 at Kyushu University Hospital. RESULTS: The primary tumor sites of the 220 cases were breast (115), colon (29), stomach (19), and pancreas (20). The present dataset suggested that homologous recombination repair (HRR) gene alterations were positively associated with tumor mutational burden-high (TMB-high) (p = 0.0099). A public dataset confirmed that patients with HRR gene alterations had a higher TMB and showed significantly longer survival of immunotherapy. In the present study, 18 cases failed sequencing. A lower percentage of tumor cell nuclei was the most common reason for testing failures (p = 0.037). Cases that received neoadjuvant chemotherapy before sampling tended to fail testing. CONCLUSIONS: HRR gene alterations can be a potential biomarker predicting TMB-high and a good response to immunotherapy. For successful sequencing, samples with lower percentages of tumor cell nuclei and previous neoadjuvant chemotherapy should be avoided.

Multiple angiosarcomas of both breasts: a case report.

BACKGROUND: Primary angiosarcomas of the breast are rare and highly aggressive. We herein report a rare case of multiple angiosarcomas detected concurrently in both breasts. CASE PRESENTATION: A 49-year-old woman visited a doctor after noticing a lump in her right breast. At that time, mammography and ultrasonography revealed no abnormal findings in either breast. She was referred to our hospital 5 months later, because screening mammography had revealed a focal asymmetric density in her right breast. Ultrasonography showed ill-defined hyper- and hypo-echoic lesions in both breasts. Magnetic resonance imaging disclosed five heterogeneously enhanced masses (5.8 cm in maximum diameter) in the right breast and six enhanced masses (approximately 1-3 cm in diameter) in the left breast. Histological examination of core needle biopsies revealed proliferation of irregularly shaped vascular channels lined by atypical endothelial cells throughout the adipose tissue and lobules of the breasts, leading to a diagnosis of well-differentiated angiosarcoma. The lesions were assumed to be primary angiosarcomas, because she had neither a history of breast surgery nor of radiation therapy. She underwent bilateral mastectomies and postoperative chest wall irradiation. Computed tomography 11 weeks after the surgery revealed multiple, small, subcutaneous nodules in the chest wall that were suspected of being angiosarcoma metastases. We started chemotherapy (weekly paclitaxel 80 mg/m2), which achieved shrinkage of these nodules within 2 months. CONCLUSIONS: Early diagnosis, immediate initiation of local and systemic therapies, and intensive follow-up are important in improving the prognosis of angiosarcomas.

Anaplastic lymphoma kinase-positive inflammatory myofibroblastic tumor of the breast: a case report and review of the literature.

BACKGROUND: Few reports of inflammatory myofibroblastic tumor (IMT) of the breast have been published worldwide. Furthermore, primary anaplastic lymphoma kinase (ALK)-positive IMT of the breast is extremely rare. To date, only six patients with ALK-positive IMT have been reported in the literature. CASE PRESENTATION: A 52-year-old woman underwent a medical examination, and a left breast mass was detected. She did not feel a mass in her chest. Mammography showed a focal asymmetric density at the lower outer portion of the left breast. Breast ultrasonography showed a 1.2-cm hypoechoic lesion with relatively clear boundaries and poor blood flow. Magnetic resonance imaging and computed tomography revealed a solitary heterogeneous mass in the left breast. Pathologic examination revealed a fibrosing lesion with proliferation of fibroblastic cells arranged in a storiform pattern and admixed inflammatory cells. Immunohistochemical examination showed that the tumor cells were positive for ALK. Under the preoperative diagnosis of IMT, we performed partial mastectomy with adequate margins. The postoperative diagnosis was pathologically confirmed as IMT. Immunohistochemical staining also showed overexpression of ALK-1 in the tumor. The patient had a good clinical course for 24 months postoperatively, without recurrence or metastasis. CONCLUSIONS: IMT of the breast shows nonspecific imaging findings, making preoperative diagnosis difficult. Nevertheless, IMT has the characteristics of low-grade neoplasms with recurrence, invasion, and metastatic potential. Our report emphasizes the importance of determining a treatment plan as soon as possible based on an accurate diagnosis to improve the prognosis of this disease.

CCND1 Copy Number Variation in Circulating Tumor DNA from Luminal B Breast Cancer Patients.

BACKGROUND/AIM: Abnormalities in the cyclin D1-CDK4/6 complex have been implicated in breast cancer proliferation and resistance to treatment. Recently, new drugs have been developed to target CDK4/6. Meanwhile, liquid biopsy has received great interest in oncology. In this study, we analyzed cyclin D1 gene (CCND1) copy number variation (CNV) in circulating tumor DNA (ctDNA) from luminal B breast cancer patients. PATIENTS AND METHODS: This study included 31 patients with luminal B breast cancer who underwent resection. We analyzed CCND1 CNV in ctDNA by digital droplet PCR. RESULTS: Of the 31 luminal B breast cancers, CCND1 CNV was positive in 5 cases. Patients with CCND1 CNV positivity had significantly shorter recurrence-free survival than patients with negative CCND1 CNV. CONCLUSION: CCND1 CNV in ctDNA was associated with poor prognosis in patients with luminal B breast cancer. This biomarker could be a useful prognostic factor.

Validity of the prognostication tool PREDICT version 2.2 in Japanese breast cancer patients.

INTRODUCTION: PREDICT is a prognostication tool that calculates the potential benefit of various postsurgical treatments on the overall survival (OS) of patients with nonmetastatic invasive breast cancer. Once patient, tumor, and treatment details have been entered, the tool will show the estimated 5-, 10-, and 15-year OS outcomes, both with and without adjuvant therapies. This study aimed to conduct an external validation of the prognostication tool PREDICT version 2.2 by evaluating its predictive accuracy of the 5- and 10-year OS outcomes among female patients with nonmetastatic invasive breast cancer in Japan. METHODS: All female patients diagnosed from 2001 to 2013 with unilateral, nonmetastatic, invasive breast cancer and had undergone surgical treatment at Kyushu University Hospital, Fukuoka, Japan, were selected. Observed and predicted 5- and 10-year OS rates were analyzed for the validation population and the subgroups. Calibration and discriminatory accuracy were assessed using Chi-squared goodness-of-fit test and area under the receiver operating characteristic curve (AUC). RESULTS: A total of 636 eligible cases were selected from 1, 213 records. Predicted and observed OS differed by 0.9% (p = 0.322) for 5-year OS, and 2.4% (p = 0.086) for 10-year OS. Discriminatory accuracy results for 5-year (AUC = 0.707) and 10-year (AUC = 0.707) OS were fairly well. CONCLUSION: PREDICT tool accurately estimated the 5- and 10-year OS in the overall Japanese study population. However, caution should be used for interpretation of the 5-year OS outcomes in patients that are ≥65 years old, and also for the 10-year OS outcomes in patients that are ≥65 years old, those with histologic grade 3 and Luminal A tumors, and in those considering ETx or no systemic treatment.

Comprehensive molecular profiling broadens treatment options for breast cancer patients.

Precision oncology with next generation sequencing (NGS) using tumor tissue with or without blood has begun in Japan. Tumor molecular profiling tests are available, including the OncoGuide™ NCC Oncopanel System and FoundationOne® CDx (F1CDx). Our purpose was to identify potentially actionable genetic alterations in breast cancer with this comprehensive tumor profiling test. We enrolled 115 patients with pathologically diagnosed advanced or metastatic breast cancer. Comprehensive tumor genomic profiling, microsatellite instability, and tumor mutational burden (TMB) were determined using F1CDx. Testing was successful in 109/115 cases (94.8%). Clinically actionable alterations were identified in 76% of advanced breast cancer patients. The most frequent short variants were in TP53 (48.6%), PIK3CA (38.5%), GATA3 (11.0%), PTEN (11.0%), and BRCA1 (10.1%), and structural variants were in ERBB2 (24.8%), MYC (21.1%), RAD21 (21.1%), CCND1 (11.9%), FGF19 (10.1%), and PTEN (10.1%). Regarding human epidermal growth factor receptor (HER)2 status, 106/109 samples (97.2%) were concordant between F1CDx and HER2 testing with immunohistochemistry/fluorescence in situ hybridization. However, ERBB2 amplification was newly detected in four samples and ERBB2 mutations were detected in five HER2-negative breast cancer samples. Oncogenic BRCA mutations were found in three samples with F1CDx among 27 germline testing-negative samples. The mean TMB in all samples was 6.28 mut/Mb and tended to be higher in luminal B and triple-negative breast cancer (mean = 8.1 and 5.9 mut/Mb, respectively) compared with other subtypes. In conclusion, we established a system for precision oncology and obtained preliminary data with NGS as the first step. The information in this clinical sequencing panel will help guide the development of new treatments for breast cancer patients.

Microsatellite instability in Japanese female patients with triple-negative breast cancer.

BACKGROUND: It is important to identify biomarkers for triple-negative breast cancers (TNBCs). Recently, pembrolizumab, an immune checkpoint inhibitor (ICI) for programmed cell death 1 (PD-1), was approved as a treatment strategy for unresectable or metastatic tumor with high-frequency microsatellite instability (MSI-H) or mismatch repair deficiency, such as malignant melanoma, non-small cell lung cancer, renal cell cancer and urothelial cancer. In addition, results from clinical trials suggested that ICI was a promising treatment for TNBCs with accumulated mutations. However, the frequency of MSI in Japanese TNBCs still remains unclear. We aimed to analyze the presence of MSI-H in TNBCs as a biomarker for ICI therapy. METHODS: In this study, we retrospectively evaluated the MSI of 228 TNBCs using an innovative method, MSI Analysis System Version 1.2 (Promega), consisting of 5 microsatellite markers: BAT-26, NR-21, BAT-25, MONO-27 and NR-24 without a normal tissue control. RESULTS: Among 228 tumors, 222 (97.4%) were microsatellite stable, 4 (1.7%) low-frequency MSI and 2 (0.9%) MSI-H, respectively. Two MSI-H tumors were potentially aggressive pathologically as indicated by nuclear grade 3 and high Ki-67 (> 30%), and were classified as basal-like and non-BRCA-like, but were not consistent regarding tumor-infiltrating lymphocytes, CD8 and PD-L1 expression. CONCLUSIONS: Although we found that MSI-H was uncommon (0.9%) in TNBCs, potential targets for ICIs exist in TNBCs. Therefore, MSI-H breast cancer patients should be picked up using not only conventional methods but also platforms for comprehensive genomic profiling.

T-bet+ lymphocytes infiltration as an independent better prognostic indicator for triple-negative breast cancer.

PURPOSE: T-box transcription factor 21 (T-bet), which is the master regulator of effector T-cell activation, is derived by stimulation of T-cell receptors. In this study, we focused on T-bet and examined the function of activated T cells. METHODS: This study included 242 patients with primary triple-negative breast cancer (TNBC) who underwent resection without neoadjuvant chemotherapy between January 2004 and December 2014. The immunohistochemistry scoring for CD8 and T-bet expression on tumor-infiltrating lymphocytes (TILs) was defined as ≥ 30 per 6.25 × 10-3 mm2. RESULTS: Of the 242 TNBC cases, CD8 was positively expressed in 127 (52.5%) tumors, and T-bet was positively expressed in 67 (27.7%) tumors. T-bet expression was significantly correlated with CD8 expression (p < 0.0001). Patients with T-bet+ tumors had longer overall survival (OS) compared with patients with T-bet- tumors (p = 0.047). The combination of CD8+ and T-bet+ was associated with a better recurrence-free survival (RFS) and OS compared to CD8+/T-bet- tumors (p = 0.037 and p = 0.024, respectively). Adjuvant chemotherapy provided significantly greater benefit to patients with T-bet+ tumors (p = 0.031 for RFS, p = 0.0003 for OS). Multivariate analysis revealed that T-bet expression on TILs was an independent and positive prognostic indicator (HR = 0.36, 95% confidence interval (CI) 0.12-0.94, p = 0.037 for RFS, HR = 0.30, 95% CI 0.07-0.95, p = 0.039 for OS). CONCLUSIONS: OS was significantly improved for patients with high T-bet-expressing TILs in TNBC. Thus, T-bet may be a predictive indicator for survival and various immunotherapy strategies in TNBC.

QOL-enhancing surgery for patients with HER2-positive metastatic breast cancer.

The role of the resection of primary tumour in stage IV breast cancer is unclear. Systemic therapy is recommended to prolong the survival and improve the quality of life (QOL). However, even if the systemic therapy is effective to control distant metastasis, sometimes the local lesion worsens, especially in the aggressive subtypes such as HER2-positive breast cancer. In uncontrollable tumours, the wound bed can bleed, weep and get infected, leading to dismal QOL. Our study describes two cases of patients with HER2-positive stage IV breast cancer who underwent palliative mastectomy which resulted in improvement of QOL. Local tumour control through palliative mastectomy can be beneficial for symptomatic aggressive patients with HER2-positive breast cancer to improve their QOL.

[Significance of Endocrine Therapy for Unresected Primary Breast Cancer].

At present, surgery is still the recommended principal treatment for breast cancer. However, there are conditions in which surgery is not suitable, for example in elderly or high-risk patients and those who do not wish to undergo the procedure. This study presents a case series of 8 patients with unresected breast cancer who were administered hormonal therapy as an optional treatment. Patients included in the study were diagnosed with Stage I-III breast cancer from 2012 to 2015 at our institution. The patients were administered hormonal therapy for an average duration of 20.1 months. Complete responses were seen in 4 patients, while 1 and 3 patients were noted to have a partial response and stable disease, respectively. No disease progression was seen in any patients during the study period. Endocrine therapy may be an effective and safe option for patients with unresected breast cancer.

A case of primary extraskeletal osteosarcoma of the breast.

BACKGROUND: Primary sarcomas of the breast are rare and account for less than 1% of all primary breast malignancies. We experienced a case of extraskeletal osteosarcoma of the breast that had a unique clinical course and remarkable findings of mammography and magnetic resonance imaging (MRI). A review of the case reports published in the past few decades showed no reports of a case in which a calcified lesion was followed up three different times on mammography, making this a valuable case report. CASE PRESENTATION: A 52-year-old woman noticed a right breast mass and underwent a breast examination. Mammography showed a 1.5-cm coarse calcified lesion in the upper outer portion of the right breast. Because fine-needle aspiration (FNA) revealed no suspicion of malignancy, she was followed up. Sixteen months later, the tumor grew progressively to 4.5 cm in size with new calcifications that were fine and irregular in shape and density surrounding an enlarged, coarse calcified lesion. Contrast-enhanced magnetic resonance imaging (MRI) showed a high signal intensity in the periphery of the tumor. Extirpation of the tumor was indicated. The pathological findings were extraskeletal osteosarcoma. She underwent additional resection and latissimus dorsi flap reconstruction at the Department of Orthopedic Surgery. CONCLUSION: The present case suggests that mammography findings of a tumor with coarse calcifications that are not typical of benign lesions may be extraskeletal osteosarcoma. A diagnosis must be made as early as possible in order to improve the prognosis of this disease.

Catumaxomab with Activated T-cells Efficiently Lyses Chemoresistant EpCAM-positive Triple-negative Breast Cancer Cell Lines.

BACKGROUND/AIM: Epithelial cell adhesion molecule (EpCAM) is expressed in various types of cancer, including breast cancer, and is correlated with metastasis, invasion, therapeutic resistance and prognosis. Moreover, several cell surface markers, such as CD44 and EpCAM, are molecular targets on cancer stem-like cells of breast cancer. The aim of this study was to investigate whether catumaxomab, a clinical-grade bispecific antibody that binds to both EpCAM on tumor cells and CD3 on T-cells, combined with activated T-cells can eliminate chemoresistant triple-negative breast cancer (TNBC) cells in vitro. MATERIALS AND METHODS: First, a cell line (MUK-BC1) was established from human breast carcinoma cells derived from a patient with chemoresistant and disseminated breast cancer. These EpCAM-positive TNBC cells were almost completely resistant to various drug-mediated cytotoxicities up to a concentration of 10 µg/ml. RESULTS: Pre-treatment with catumaxomab and subsequent addition of interleukin-2/OKT3-activated autologous T-cells eliminated EpCAM-positive TNBC cells. CONCLUSION: Catumaxomab combined with activated T-cells may be a potent therapeutic modality to overcome chemoresistant EpCAM-positive TNBC cells.

Efficacy and Safety of Bi-weekly Pegfilgrastim for Dose-dense Chemotherapy-induced Neutropenia in Breast Cancer Patients.

BACKGROUND/AIM: The dose-dense doxorubicin and cyclophosphamide (ddAC) for patients with HER-2-negative breast cancer is recommended by the National Comprehensive Cancer Network guideline in US. However, there are little data on serum G-CSF concentrations in patients undergoing bi-weekly dose-dense therapy with pegfilgrastim. The objective of this study was to compare the serum G-CSF concentrations in patients receiving pegfilgrastim in bi- or tri-weekly regimens. PATIENTS AND METHODS: This study included 26 patients who received ddAC or docetaxel and cyclophosphamide (TC) for primary breast cancer. Serum G-CSF concentrations were measured by ELISA. RESULTS: Serum G-CSF concentrations peaked in the second week of ddAC cases and in the ninth week of TC cases. Neutrophils gradually increased until the sixth week in ddAC cases, while they were slightly decreased during the first three weeks in TC cases. Treatments were completed without febrile neutropenia or treatment delays. CONCLUSION: Primary prophylactic pegfilgrastim administrations increased serum G-CSF concentrations, helping to maintain the absolute neutrophil counts that are required to undergo chemotherapy. The treatment of ddAC with 3.6 mg pegfilgrastim is completely safe for female Japanese patients.

BRCAness Combined With a Family History of Cancer Is Associated With a Poor Prognosis for Breast Cancer Patients With a High Risk of BRCA Mutations.

BACKGROUND: The inexpensive prediction of the characteristics of BRCA-mutated breast cancer as "BRCAness" using the somatic cells of patients with breast cancer could be useful for developing a therapeutic strategy. Our objective was to correlate BRCAness with the clinicopathologic features, including a family history (FH) of cancer, in breast cancer patients with a high risk of BRCA mutations. PATIENTS AND METHODS: The present study included 124 patients, including 55 with early-onset and 77 with triple-negative breast cancer, who had undergone resection at Kyushu University Hospital from 2005 to 2014. Early-onset breast cancer is defined as an onset in patients aged ≤ 40 years. BRCAness was performed using multiple ligation-dependent probe amplification. The patients' FH of cancer was surveyed from first- to third-degree relatives. RESULTS: Of the 124 patients, the multiple ligation-dependent probe amplification assay results indicated that 59 tumors (47.6%) had BRCAness and 27 patients (21.8%) had a positive FH for cancer. The patients with BRCAness experienced significantly shorter recurrence-free survival (RFS) and overall survival (OS) compared with those without. Patients with FH had shorter RFS and OS compared to those without BRCAness. The patients were divided into those with and without BRCAness and those with and without a positive FH. The BRCAness with FH subgroup experienced significantly shorter RFS and OS. Multivariate analysis revealed that BRCAness and a positive FH were independent negative prognostic factors. CONCLUSION: Our findings suggest that BRCAness tumors with a positive FH of cancer were associated with a poor prognosis in the BRCA-mutation high-risk group. We propose that BRCAness and a positive FH will serve to predict patients' prognosis.

[Mediastinal Hemangioma with Literature Review;Report of a Case].

A 58-year-old woman visited a local physician for evaluation of collagen disease and screening computed tomography (CT) showed a posterior mediastinal tumor. After referral to our hospital, CT and magnetic resonance imaging (MRI) showed a mass, approximately 2 cm in diameter, located on the right of the 1st thoracic vertebra. Since a neurogenic tumor was suspected, thoracoscopic excision was performed. Surgical findings revealed a tumor between the 1st and 2nd ribs in the close vicinity of the right brachiocephalic vein. We severed blood vessels flowing into the tumor and removed it. The tumor, 25 mm in maximal diameter, was diagnosed as hemangioma by histological examinations. The prevalence of a hemangioma is less than 0.5% of all mediastinal tumors. Since it lacks specific imaging findings, its preoperative diagnosis is quite difficult to establish. Although a hemangioma in the mediastinum is quite rare, it should be included in the differential diagnoses of mediastinal tumors.

Phase II trial of carboplatin, S-1, and gefitinib as first-line triplet chemotherapy for advanced non-small cell lung cancer patients with activating epidermal growth factor receptor mutations.

Gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is an effective treatment for advanced non-small cell lung cancer (NSCLC) in patients with activating EGFR mutations. However, there have been little evidence-based studies of gefitinib in combination with platinum-doublet therapy in these patients. We performed a phase II trial to determine the efficacy and safety of triplet chemotherapy with gefitinib, carboplatin, and S-1 as a first-line treatment. This was a multicentre, single-arm, phase II trial of carboplatin, S-1, and gefitinib in advanced NSCLC patients with activating EGFR mutations. Patients received four courses of these drugs in 3-4 week cycles. In each cycle, carboplatin (area under curve = 5) was administered on day 1, S-1 (80 mg/m(2)) on days 1-14, and gefitinib (250 mg) every day. Subsequently, the same regimen without carboplatin was administered until disease progression or unacceptable toxicity occurred. The 1-year progression-free survival (PFS) was the primary endpoint, while response rate (RR), PFS, overall survival (OS), and safety were secondary endpoints. Thirty-five patients were enrolled into this study. The 1-year PFS was 74.3% and the overall RR was 85.7%. The median PFS for all patients was 17.6 months (95% confidence interval 15.5-∞), but the median OS was not reached, because 28 patients were still alive after a median follow-up time of 21.4 months. Haematological adverse events (grade 3 or higher) included neutropaenia (17.1%), thrombocytopenia (14.3%), and anaemia (5.7%), while non-haematological adverse events (grade 3 or higher) included elevated aminotransferase (20.0%), diarrhoea (14.3%), and febrile neutropaenia (2.9%). No interstitial lung disease or treatment-related deaths occurred. Combination chemotherapy with carboplatin, S-1, and gefitinib is efficacious and well tolerated as a first-line treatment in advanced NSCLC patients with activating EGFR mutations.

Important factors for achieving survival of five years or more in non-small cell lung cancer patients with distant metastasis.

In order to examine which factors were important for achieving a ≥5 year survival time in non-small cell lung cancer (NSCLC) patients with distant metastasis, 268 NSCLC patients who received first-line chemotherapy between January 2004 and December 2007 were retrospectively examined. The median survival time of the patients was 14 months, with 22 surviving for ≥5 years, 48 for ≥2 years, but <5 years, and 198 surviving <2 years. Multivariate analysis determined that never having smoked, a good performance status, relapse following thoracic surgery and intra-thoracic metastasis were significantly favorable prognostic factors, while abdominal metastasis was a significantly poor prognostic factor. The ≥5 years and ≥2-5 years groups had significantly more favorable prognostic factors than the <2 years group. The never-smoked status was a particularly important factor for ≥5 years of survival. The ≥5 years and ≥2-5 years groups achieved a significantly more favorable response to first-line chemotherapy, and a greater number of regimens, total months of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) treatment and cytotoxic agent treatment cycles compared with the <2 years group. In total, ~50% of the patients received palliative radiotherapy. In the ≥5 years group, patients with EGFR drug-sensitive mutations achieved ≥5 years of survival mainly by EGFR-TKI therapy, while those without EGFR mutations achieved ≥5 years of survival by continuing effective cytotoxic agents. Achievement of >5 years of survival was found to correlate with the presence of favorable prognostic factors, response to first-line chemotherapy, provision of appropriate EGFR-TKI therapy according to genetic testing results, continuing effective cytotoxic regimens and the use of radiotherapy as local therapy.

Usefulness of high suction pressure for sufficient tissue collection during endobronchial ultrasound guided transbronchial needle aspiration.

INTRODUCTION: The optimal suction pressure during endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) remains to be determined. The aim of this study was to compare suction pressures for performance in collecting sufficient tissue specimens from mediastinal and hilar lymph nodes during EBUS-TBNA. METHODS: Retrospective analysis of consecutive patients with mediastinal and hilar lymphadenopathy who underwent EBUS-TBNA over a 3-year period. Results from patients who underwent EBUS-TBNA using a dedicated 20-mL VacLoc (Merit Medical Systems, Inc, South Jordan, UT) syringe (conventional method, group C) were compared with results from patients in whom a disposable 30-mL syringe (high pressure group, group H) was used. The yield for sufficient histologic specimen retrieval and amount of tissue obtained were compared between the 2 groups. RESULTS: Of 178 patients who underwent EBUS-TBNA, 131 had lung cancer confirmed by EBUS-TBNA: 35 in group C and 96 in group H. There were 7 patients in group C and 6 in group H who received final diagnoses by cytology alone. There were 28 in group C and 90 in group H who were diagnosed by both cytology and histology. There was a statistically significant difference between the groups in terms of the rate of sufficient sampling for histological specimens (p = 0.04). The H group revealed a tissue area approximately twice that of the C group (p = 0.003). There were no major procedure-related complications in either group. CONCLUSION: Higher suction pressures with larger syringe volumes during EBUS-TBNA may be useful for safely collecting sufficient tissue specimens.