Synchronous Multiple Lung Cancer Research Articles

Genomic heterogeneity of multiple synchronous lung cancers in Chinese population.

It is clinically challenging to infer the phylogenetic relationship between different tumor lesions of patients with multiple synchronous lung cancers (MSLC), whether these lesions are the result of independently evolved tumor or intrapulmonary metastases. We used the Illumina X10 platform to sequence 128 stage I lung cancer samples collected from 64 patients with MSLC. All samples were analyzed for mutation spectra and phylogenetic inference. We detected genetic aberrations within genes previously reported to be recurrently altered in lung adenocarcinoma including, EGFR, ERBB2, TP53, BRAF, and KRAS. Other putative driver mutations identified were enriched in RTK-RAS signaling, TP53 signaling, and cell cycle. Also, we found some interesting cases, two cases that carried EGFR L858R and T790M co-mutation in one tumor and another tumor with only EGFR 19del, and 1 case with two KRAS hotspots in the same tumor. Due to the short follow-up time and early stage, further investigation is needed to determine whether this unique mutation profile will affect their progression-free survival (PFS) and overall survival (OS). Regarding genetic evolution analysis among 64 tumor samples, 50 of them display distinct mutational profiles, suggesting these are independently evolved tumors, which is consistent with histopathological assessment. On the other hand, six patients were identified to be intrapulmonary metastasis as the mutations harbored in different lesions are clonally related. In summary, unlike intrapulmonary metastases, patients with MSLC harbor distinct genomic profiles in different tumor lesions, and we could distinguish MSLC from intrapulmonary metastases via clonality estimation.

Case report: targeted sequencing improves the diagnosis of multiple synchronous lung cancers

Case report: targeted sequencing improves the diagnosis of multiple synchronous lung cancers

Application Value of PET/CT and MRI in the Diagnosis and Treatment of Patients With Synchronous Multiple Pulmonary Ground-Glass Nodules.

BackgroundSynchronous multiple ground-glass nodules (SMGGNs) in synchronous multiple lung cancers are associated with specific imaging findings. It is difficult to distinguish whether multiple nodules are primary tumors or metastatic lesions in the lungs. The need for PET/CT and contrast-enhanced brain MRI for these patients remains unclear. This study investigated the necessity of these two imaging examinations for SMGGN patients by means of retrospective analysis.MethodsSMGGN patients who were diagnosed and treated in our hospital from October 2017 to May 2020 and underwent whole-body PET/CT(Cranial excepted) and/or contrast-enhanced brain MRI+DWI were enrolled in this study. We analyzed the imaging and clinical characteristics of these patients to evaluate SMGGN patients’ need to undergo whole-body PET/CT and brain MRI examination.ResultsA total of 87 SMGGN patients were enrolled. 51 patients underwent whole-body PET/CT examinations and did not show signs of primary tumors in other organs, metastatic foci in other organs, or metastasis to surrounding lymph nodes. 87 patients underwent whole-brain MRI, which did not reveal brain metastases but did detect an old cerebral infarction in 23 patients and a new cerebral infarction in one patient. 87 patients underwent surgical treatment in which 219 nodules were removed. All nodules were diagnosed as adenocarcinoma or atypical adenomatous hyperplasia. No lymph node metastasis was noted.ConclusionFor SMGGN patients, PET/CT and enhanced cranial MRI are unnecessary for SMGGNs patients, but from the perspective of perioperative patient safety, preoperative MRI+DWI examination is recommended for SMGGNs patients.

Preoperative non-invasive visual localization of synchronous multiple lung cancers using three-dimensional computed tomography lung reconstruction

BackgroundSynchronous multiple primary lung cancers are becoming more common with increasing use of computed tomography for screening. Intraoperative localization and resection of ill-defined pulmonary ground-glass opacities during thoracoscopic resection is challenging. This study aimed to determine the clinical feasibility of non-invasive visual localization of these nodules by three-dimensional computed tomography lung reconstruction before sublobar resection.MethodsForty-four patients with synchronous multiple primary lung cancers underwent thoracoscopic pulmonary resection at our institution between June 2017 and August 2019. Preadmission computed tomography images were downloaded and reconstructed into a three-dimensional model. Small nodules (< 15 mm) were localized non-invasively by three-dimensional computed tomography lung reconstruction before surgery. Patient demographics, nodule characteristics, procedural details, pathological data, and outcomes were obtained from the medical records.ResultsOne hundred and twenty-one pulmonary nodules from the 44 patients were scheduled for video-assisted thoracic surgery; 54 (44.6%) were pure ground-glass opacities and 57 (47.1%) were mixed ground-glass opacities. One hundred and seventeen nodules were localized preoperatively. The mean nodule diameter was 7.67 ± 3.87 mm. The mean distance from the nodule to the pleura was 14.84 ± 14.43 mm. All nodules were removed successfully by wedge resection (27 patients), lobectomy (26 patients), or segmentectomy (25 patients). Most lesions (85.1%) were malignant. Paraffin pathology revealed 12 cases of atypical adenomatous hyperplasia (9.92%), 13 of adenocarcinoma in situ (10.74%), 16 of minimally invasive adenocarcinoma (13.22%), and 73 of invasive adenocarcinoma (60.33%).ConclusionsThree-dimensional computed tomography lung reconstruction is a feasible and alternative method of visual localization for small lung nodules before sublobar resection in some suitable patients.

P06.01 Therapeutic Strategies for Metachronous Multiple Primary Lung Cancer

It is not uncommon to encounter metachronous primary lung cancer after surgical treatment along with the increase in the elderly patients. In consideration of increasing number of such patients, it is necessary to take various treatment strategies. Method: In order to establish a treatment strategy for multiple lung cancer, we retrospectively examined multiple lung cancer cases operated for primary lung cancer in our department from January 2013 to December 2018, and the future treatment strategy was examined. In order to establish a treatment strategy for multiple lung cancer, we retrospectively examined multiple lung cancer cases operated for primary lung cancer in our department from January 2013 to December 2018, and the future treatment strategy was examined. Of 821 patients who underwent surgery for primary lung cancer, 60 were multiple lung cancers, 31 were synchronous multiple lung cancers, and 29 were metachronous multiple lung cancers. Among the cases of metachronous multiple lung cancer, 27 cases had undergone lobectomy or more in the first operation, 1 case of segmental resection, and 1 case of partial resection. As for the treatment of secondary lung cancer lesions, 20 lesions were performed surgery (lobectomy; 1, segmental resection;5, partial resection; 14), 6 lesions of photodynamic therapy (PDT), and 3 lesions of SBRT. Among the surgical cases, there were 3 cases on the same side as the first cancer and 17 cases on the opposite side. The three cases underwent partial resection. Among 17 patients, postoperative home oxygen therapy was introduced in 2 patients. Regarding the prognosis, three patients who had surgical resection, died of recurrence of the first lesion. Two of the six PDT patients died of recurrence of the first lung cancer and one died of other disease. All three patients who underwent SBRT are alive without recurrence. If early detection and early diagnosis are made as a treatment strategy for metachronous multiple lung cancer, it may be possible to preserve lung function by reducing surgery or SBRT, PDT, and to cure without damaging the quality of life.

ES25.04 Multiple Pulmonary Lesions: Metastasis vs Multiple Primaries, From Martini's Criteria to Molecular Profiling

ES25.04 Multiple Pulmonary Lesions: Metastasis vs Multiple Primaries, From Martini's Criteria to Molecular Profiling

Synchronous Multiple Lung Cancers with Lymph Node Metastasis and Different EGFR Mutations: Intrapulmonary Metastasis or Multiple Primary Lung Cancers?

BackgroundThere is no consensus on whether patients with synchronous multiple lung cancers (SMLC) who present with lymph node metastasis (LNM) but whose epidermal growth factor receptor (EGFR) mutations are different are considered to have intrapulmonary metastases or multiple primary lung cancers. Few studies on these patients have been reported.MethodsThe electronic medical records of patients with surgically resected multiple lung cancers between February 2016 and July 2019 were retrospectively reviewed, focusing on the clinical characteristics and prognosis of patients with LNM and different EGFR mutations.ResultsA total of 125 patients were diagnosed with SMLC, and only 8 patients had LNM and different EGFR mutations. Their mean age was 61.43 ± 8.08 years (range 47–69 years). EGFR detection suggested that 4 patients had completely different mutation types, and 4 patients had mutations in only 1 tumor. Only 1 of the 17 total lesions was squamous cell carcinoma, the rest were adenocarcinoma. All patients underwent adjuvant therapy after surgery. Except for 1 patient who underwent chemotherapy, the rest received tyrosine kinase inhibitor-targeted therapy. As at 15 October 2020, the average follow-up time was 28.68 ± 10.74 months (range 10.5–40.5 months), and all patients were alive except 1 who died from extensive pleural metastasis.ConclusionThe current study highlights the clinical importance of EGFR detection in SMLC, especially in patients with LNM. SMLC with LNM and different EGFR mutations should be considered multiple primary lung cancers rather than intrapulmonary metastases, and comprehensive treatment based on surgery may be preferable in these patients due to a good prognosis.

1448P - Genomic heterogeneity and clonality analysis of multiple synchronous lung cancers (MSLCs)

BackgroundIt is clinically challenging to infer the phylogenetic relationship between different tumor lesions of patient with multiple synchronous lung cancers MSLC: whether these lesions are the result of independently evolved tumor or intrapulmonary metastases. MethodsUsing Illumina X ten platform, we sequenced a total number of 49 lung adenocarcinoma samples collected from 24 patients with MSLC. All samples were analyzed for mutation spectra and phylogenetic inference. Clonality estimation was further carried out to determine the mutational similarity of different tumor lesions. ResultsAmong 24 patients, 17 of them display distinct mutational profile, suggesting these are independently evolved tumors, which is consistent with histopathological assessment. The phylogenetic analysis suggests that multiple cancerous lesions in these patients most likely evolve from different progenitor cells. On the other hand, seven patients were identified to be intrapulmonary metastasis as the mutations harbored in different lesions are clonally related. The mutation spectra of single-nucleotide variations (SNVs) were fairly consistent across different cancerous lesion within all patients. We detected genetic aberrations within genes previously reported to be recurrently altered in lung adenocarcinoma including KRAS, MET, EGFR, TP53, and BRAF. Other identified putative driver mutations are enriched in RTK-RAS signaling, TP53 signaling and cell cycle. ConclusionsOur findings show that, unlike intrapulmonary metastases, patients with MSLC harbor distinct genomic profile in different tumor lesions and we are able to distinguished MSLC from intrapulmonary metastases via clonality estimation. This study delineates the evolutionary trajectories of MSLCS and shed light on better therapeutic strategy and prognosis. Legal entity responsible for the studyThe First Affiliated Hospital of Dalian Medical University. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Synchronous multiple lung cancers presenting as multifocal pure ground glass nodules: are whole-body positron emission tomography/computed tomography and brain enhanced magnetic resonance imaging necessary?

Multifocal ground glass nodules (GGNs) represent a special radiological pattern indicative of synchronous multiple lung cancers (SMLCs), especially adenocarcinoma. However, the necessity of performing whole-body positron emission tomography/computed tomography (PET-CT) scanning and brain enhanced magnetic resonance imaging (MRI) as a staging workup for multifocal pure GGN (pGGN) patients remains unclear. The purpose of this study was to determine the utility of these two imaging scans for patients with multifocal pGGNs. This retrospective study was reviewed and approved by the ethics committee of the Cancer Hospital of the Chinese Academy of Medical Sciences. The study cohort was retrospectively selected from patients with multifocal pGGNs who underwent whole-body PET-CT examinations and/or brain enhanced MRIs between January 2010 and February 2019 at our institution. The additional value of the two exams for detecting nodal and distant metastases was evaluated. In total, 73 patients (male-to-female ratio, 20:53; median age, 57 years) with multifocal pGGNs who underwent whole-body PET-CT (55 patients) and/or brain enhanced MRI (25 patients) were enrolled. No clearly metastatic lesions were detected. Among the enrolled patients, 53 (128 pGGNs) underwent complete surgical resection. All pGGNs were adenocarcinomas and/or preneoplasias, and no lymph node metastases were found on final pathology. Whole-body PET-CT and brain enhanced MRI added no definite benefit compared with chest CT alone before surgery. Whole-body PET-CT scans and brain enhanced MRIs are not necessary for patients with multifocal pGGNs.

EP1.17-01 Surgical Resection of Synchronous Quadruple Primary Lung Tumors Present as Three-Different Cancers and One Benign Mass

Synchronous triple lung cancer is uncommon and little is known, making it difficult to establish proper guidelines or treatment strategies. In this report, we describe a 70-year-old male with three synchronous independent and histologically different primary cancers and one benign hamartoma. Chest CT showed a 30 mm-sized lobulated lung mass in posterior basal segment of the left lower lobe (tumor 1) (Figure 1A). In addition, there were another 26 mm-sized well defined solid nodule in the right lower lobe (tumor 2) (Figure 1A). Two sub-centimeter nodules were also presented in superior segment of the right lower lobe (tumor 3) (Figure 1B) and the lingular segment of the left upper lobe (tumor 4) (Figure 1B). A transthoracic percutaneous needle aspiration biopsy performed on the 30 mm-sized nodule in the left lower lobe revealed it as squamous cell carcinoma. During the right side surgery, intraoperative frozen biopsy of tumor 2 and tumor 4 were reported as chondroid hamartoma and adenocarcinoma, respectively. As we already knew that the left side tumor was squamous cell carcinoma, we decided to continue left side surgery with mediastinal lymph node dissection. The final results of the pathological examination of tumor 1 showed squamous cell carcinoma of pT2bN1M0 (Figure 2A), stage IIB. Tumor 2 was diagnosed as chondroid hamartoma (Figure 2B). Small nodules located in the right lower lobe (tumor 3) and left upper lobe (tumor 4) were 6 mm-sized adenocarcinoma with visceral pleural invasion (pT2aNx) (Figure 2C) and 7 mm-sized adenoid cystic carcinoma (pT1aN0) (Figure 2D), respectively. There was no recurrence during the 3-year follow-up period. Appropriate preoperative staging work up including HRCT and percutaneous needle aspiration biopsy can allow timely detection of synchronous multiple lung cancer, offer proper surgical strategy, and give the possibility of implementing potentially curative treatment for patients conventionally misdiagnosed or considered as metastasized.

THE RESULTS OF SURGICAL TREATMENT OF PATIENTS WITH MULTIPLE PRIMARY LUNG CANCERS ACCORDING TO ORENBURG REGIONAL ONCOLOGICAL CLINIC DATA

Aim. To assess the immediate and long-term results of treating patients with bilateral lung cancer (LC). Patients and methods. Radically operated 5 patients with primary multiple synchronous LC (PMSLC) and 5 patients with primary multiple metachronous LC (PMMLC) were included in the study. Clinical and morphological data, results of instrumental studies, immediate and long-term treatment results were analyzed. Statistical analysis was performed using the Statistica6 software. Results. Tumors corresponding to T1‑T2 prevailed in both groups. At the same time, both in the PMSLC and PMMLC group, only in one case both tumors corresponded to T1–2N0M0, in the others — one or both tumors were with metastases in lymph nodes of the root or mediastinum. In early postoperative period, the number of surgical complications was 10%, somatic — 20%. All complications were successfully treated conservatively. Postoperative mortality was not observed. In PMMLC and PMSLC cases, one-year relapse-free survival (RFS) was 100% and 80%; two-year — 80% and 60%; three-year — 60% and 60%; four-year — 60% and 20%, respectively. The five-year RFS in patients with PMMPC was 40%. One patient with PMSLC was alive without relapse of disease for 4.5 years. Accordingly, one-year overall survival (OS) was 100% and 100%; two-year — 80% and 80%; three-year — 80% and 60%; four-year — 80% and 40%. Five- and six-year OS in patients with PMMLC were 60% and 20%, respectively. Conclusion. The absence of postoperative mortality and low number of postoperative complications indicate the safety of bilateral operations in patients with bilateral LC. Low rates of patients’ 5‑year survival are connected with problems of primary diagnostics and low efficiency of existing algorithms of regular medical checkup of patients with this pathology. To improve long-term results of LC treatment, it is necessary to more actively introduce the modern programs of dynamic observation and complex examination of patients, undergone surgery for LC, using the annual chest CT and fibrobronchoscopy.

Clinicopathologic Characteristics and Prognosis of Patients With Non–Small Cell Lung Cancer Who Undergo Pulmonary Segmentectomy

This study retrospectively investigated the clinical characteristics and prognosis of the non–small cell lung cancer (NSCLC) patients who underwent segmentectomy as either intentional or passive limited surgery. The subjects included in this study comprised 72 patients who underwent segmentectomy at our hospital. There were 23 patients who underwent intentional segmentectomy. The histologic type was adenocarcinoma in all of these patients. Regarding the tumor size, 9 tumors were 1 cm or less in diameter, 13 were 1.1 to 2 cm, and 1 was 2.5 cm. All patients who underwent intentional segmentectomy were alive without any recurrence as of the last follow-up examination. A passive segmentectomy was performed for 49 patients. The reasons for passive segmentectomy were due to the presence of metachronous multiple lung cancer in 14 patients, synchronous multiple lung cancer in 9 patients, age above 80 years in 12 patients, reduced pulmonary function in 8 patients, and moderate to severe cardiovascular disease in 4 patients; another 2 patients were receiving treatment for another primary cancer. The 5-year survival rate of the patients who underwent passive segmentectomy was 69.8%. There was no postoperative mortality in either of the groups. This study showed that all of the patients who underwent intentional segmentectomy were alive without any recurrence, thus suggesting that the procedure is associated with sufficient oncologic efficacy, along with preservation of the lung function. The passive segmentectomy was a feasible procedure and was an alternative procedure with an acceptable overall survival rate in high-risk patients with underlying medical comorbidities.

Synchronous multiple lung cancer consisting of squamous cell carcinoma and adenocarcinoma with de novo T790M EGFR gene mutation

Synchronous multiple lung cancer consisting of squamous cell carcinoma and adenocarcinoma with de novo T790M EGFR gene mutation

Radiopathologic correlation of collision lung cancer with ground-glass opacity

Pulmonary collision tumors have been described as a special entity of synchronous multiple lung cancer. There have been no reports detailing the chronological changes in primary collision lung cancers on chest computed tomography. We report a case of ground-glass lung nodules gradually colliding with each other. The collision tumors of the lung were composed of minimally invasive adenocarcinoma and adenocarcinoma in situ with epidermal growth factor mutations. Immunohistochemically, the Ki-67 labeling indices were different in the 2 components. Ki-67 staining was useful to distinguish the 2 components. The 2 dominant ground-glass tumors grew slowly with radiologic and pathologic heterogeneity.

P2.09-16 Heterogeneity Analyses of MSLCs—Especially in the EGFR Mutation-Positive Ones

Multiple synchronous lung cancers (MSLCs) are diagnosed as multiple tumor nodules in the same or different lung lobes. MSLCs present a clinical dilemma whether they are primary tumors or metastases. Recent studies showed that MSLCs shared an identical germline genetic background and environmental exposure in the same individual patient, however, different tumor nodules showed highly different heterogeneity, even in all the EGFR mutation-positive focuses. Therefore, we performed this study to further analyze MSLCs as to estimate the pathology and molecule heterogeneity among these nodules. Tumor samples were obtained from nine patients diagnosed with MSLCs. Immunohistochemistry were performed by professional pathologists. Whole-exome sequencing (WES) was conducted by IlluminaNovaseq with sequencing depth of 200X. NeoTyping was used to describe the dispersion of sequencing data among MSLCs of the same patient. We found different tumor nodules showed obviously pathological and molecular heterogeneities in the same individual (Figure 1). More different dispersion was observed among the nodules with more different pathologies in the same patient. The dispersion of 20%, 50% and 100% were observed in MSLCs with the same driver genes (such as EGFR exon21 L858R and L861Q) of lung adenocarcinoma, different evolutional stages (AAH, MIA and IA) and completely different pathologies (adenocarcinoma and squamous cancer), respectively. All the sequencing data showed MSLCs had different gene information, even in all the EGFR mutation-positive nodules, maybe similar, but not the same, which supported that each nodule in one patient was independent with others. MSLCs could be independent with each other due to their pathological and molecular heterogeneities, even for EGFR mutation-positive nodules which hold the same driver gene, but different mutation site in just one patient. WES should be an effective way to recognize this heterogeneous characteristic, which would be helpful for the whole precise management of one MSLC patient.

Targeted Sequencing Analysis of Pulmonary Adenocarcinoma with Multiple Synchronous Ground-Glass/Lepidic Nodules

IntroductionLung adenocarcinoma (ADC) with synchronous ground-glass/lepidic (GG/L) nodules is considered a distinct disease entity in multiple synchronous lung cancers. Few studies have performed next-generation sequencing analysis of these synchronous sequential lesions, and genetic alterations of GG/L nodules must be further investigated. MethodsWe performed targeted sequencing in ADC with synchronous atypical adenomatous hyperplasia (AAH), ADC in situ, or minimally invasive ADC from 16 patients. Next-generation sequencing was performed by using a customized panel including 154 cancer-associated genes. ResultsMultiple synchronous lesions in the same patient showed different mutation profiles, and some shared identically mutated genes. In five patients harboring EGFR-mutant ADC, their synchronous GG/L nodules had EGFR mutation; however, none was observed in EGFR wild-type ADC. The average numbers of exonic mutations were 4.2, 5.4, 4.0, and 5.4 in AAH, ADC in situ, minimally invasive ADC, and ADC, respectively. In each lesion type, various mutations, including LDL receptor related protein 1B gene (LRP1B), KRAS, EGFR, and BRAF were observed in AAH, and EGFR mutations were the most frequently observed in ADC. In all, 80% of mutations with a variant allele frequency of 20% or higher, which contained driver gene mutations, were identified in ADC. Intratumoral heterogeneity of the genetic profile was found between the lepidic and invasive areas of ADC, but the driver gene mutations were similar. ConclusionsThis study suggests that ADC and synchronous GG/L nodules are genetically independent tumors. Intratumoral genetic heterogeneity of ADC was present, but driver gene mutations were homogeneously distributed. Driver gene mutations with a high variant allele frequency were identified in the invasive tumor. These findings support the relevance of molecular characterization of lung ADC and synchronous GG/L nodules.

Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer: A Primer for Radiologists.

The past 2 decades have seen a rapid growth in use of stereotactic body radiation therapy (SBRT) for the management of non-small cell lung cancer (NSCLC). Not only is SBRT the reference standard for treatment of early-stage node-negative NSCLC in medically inoperable patients, it is also currently challenging the role of surgery for early-stage operable disease. SBRT is also used to treat recurrent disease and has a role in the management of multiple synchronous lung cancers. Imaging changes after SBRT differ from the changes after conventional radiation therapy in many ways, the knowledge of which is pertinent for accurate image interpretation. Posttreatment response assessment and detection of recurrent disease are heavily reliant on radiologic assessment, and often the decision to treat recurrent disease is based on the imaging findings themselves. This article provides a comprehensive review of the concepts of SBRT and the current indications for its use in the treatment of early-stage NSCLC, as well as a discussion of the CT findings seen after SBRT compared with the changes after conventional radiation therapy. Radiologic findings that are suggestive of recurrent disease and the imaging pitfalls are also highlighted. Finally, the rare complications after SBRT are described. SBRT is a major component of the changing treatment paradigms for early- and late-stage NSCLC. The imaging findings after SBRT often determine the next steps in a patient's clinical management. Therefore, radiologists must be familiar with the uses of this therapy and its radiologic appearance to be able to effectively contribute to the care of patients with NSCLC. ©RSNA, 2018.

Abstract 3680: Comparative mutational evaluation for multiple lung cancer by multiplex oncogene mutation analysis

Abstract [Background] In the treatment of synchronous or metachronous multiple lung cancer (MLC), determination whether multiple primary lung cancer (MP) or intrapulmonary metastases (IM) is very important to make an appropriate management. Clinical or pathological diagnoses have been adopted to distinguish whether MLC were MP or IM, however, the accuracy of these approaches seemed to be insufficient. On the other hand, recent evolution of high-throughput sequencing made it possible to perform comprehensive gene mutation analysis in cancer cells. The aims of this study were to investigate mutational profiles of synchronous or metachronous MLC, and to compare multiplex gene mutation analysis of MP or IM among paired tumors with clinical or pathological evaluations. [Methods] We performed targeted sequencing for 20 lung cancer related oncogenes using next-generation sequencing technology in 82 tumors from 37 patients (18 patients with synchronous MLC and 19 patients with metachronous MLC) who underwent surgical resection in our department from July 2002 to April 2013. Then, classification of MP or IM was made by clinical, pathological, and gene mutational evaluation. [Results] Among paired tumors, matching of mutation was observed in 20 (54%) cases (nine cases with completely matched and 11 cases with partially matched), which were diagnosed as IM by mutational evaluation. In pathologically suggested IM cases (n=7), six (86%) patients were interpreted as IM by mutational evaluation, and most of them (n=5) had multiple matched mutations, which suggested the clonality between paired tumors strongly. In pathologically suggested MP cases (n=17), the mutational diagnosis was discordant in eight (47%) patients. Among these cases, four paired tumors had multiple matched mutation, suggesting the pathological diagnosis in these cases might be incorrect. In addition, careful interpretation was required when the paired tumors harboring frequent mutation including TP53 or EGFR because such mutation may match accidentally. [Conclusion] Our findings suggest that multiplex mutational analysis of synchronous or metachronous MLC could complement the pathological diagnosis in differentiation whether MP or IM. In the cases with pathologically equivocal or those with discordant between pathological diagnosis and mutational evaluation, the frequency and the number of matched mutation may be helpful for the differentiation. Citation Format: Yuta Takahashi, Kazuhiko Shien, Shuta Tomida, Eisuke Kurihara, Yusuke Ogoshi, Kei Namba, Takahiro Yoshioka, Hidejiro Trigoe, Hiroki Sato, Hiromasa Yamamoto, Junichi Soh, Shinichi Toyooka. Comparative mutational evaluation for multiple lung cancer by multiplex oncogene mutation analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3680.

Bilateral synchronous multiple lung nodules: Surgical experience from two cases

Synchronous multiple lung cancer (SMPLC) has been increasingly detected as a result of improved imaging techniques, though the incidence of SMPLC is rare. Surgery is currently the only treatment offering potential cure and long-term survival in patients with SMPLC, and complete resection is widely accepted as the first choice of procedure for this type. However, due to the rarity of this clinical scenario, many surgeons lack experience in surgical treatment of SMPLC. Here, we present two cases whose SMPLC was successfully managed with aggressive surgical therapy through video-assisted thoracoscopic surgery.

Synchronous bilateral lung adenocarcinomas associated with vulvar rhabdomyosarcoma in a 15-year-old girl

Abstract Pediatric malignancies are thought to be risk factors of second malignant neoplasms. However, lung cancer associated with rhabdomyosarcoma is extremely rare. When multiple pulmonary lesions are observed in cancer patients, resection is necessary to distinguish them from metastatic lesions. We report an extremely rare case of synchronous bilateral multiple lung cancers showing ground glass nodules (GGNs) associated with rhabdomyosarcoma in a 15-year-old girl with vulvar rhabdomyosarcoma. When we identify GGNs in adolescents with a history of rhabdomyosarcoma, we should consider lung cancer as a differential diagnosis in addition to pulmonary metastasis usually showing solid nodule. In the present case with tiny lesions, surgical resection using lipiodol-marking helped to ensure both an early diagnosis and curative treatment.