Multiple Primary Lung Cancer Patients Research Articles

Comprehensive germline and somatic DDR genomic profiles of Chinese patients with multiple primary lung cancer.

e20019 Background: The number of multiple primary lung cancer (MPLC) patients has rapidly increased in recent years. Disruption of the DNA damage repair (DDR) gene is related to cancer risk, progression, and treatment selection. However, the characteristics and significance of DDR alterations remain undefined in MPLC. Methods: A total of 133 Chinese MPLC patients with 308 lesions were enrolled and 784 single-focus lung cancer (SFLC) patients were analyzed as a control in the present study. Genetic testing was performed by utilizing the next-generation sequencing (NGS) of 808 cancer-related genes including 276 DDR genes. The patients were divided into 3 groups: DDR-germline (germline variants, N = 11), DDR-somatic group (somatic variants, N = 98), and the non-DDR group (no DDR variants, N = 24). Results: The overall DDR variants were identified in 82.0% (109/133) of the patients, and a total of 283 variants were found, with almost all being somatic (254/283). The most commonly germline alterations were found in RAD50 (1.5%), WRN (1.5%) and BRCA2 (0.8%), while in the somatic mutations, TP53 (26.3%) showed the highest frequency. DDR-somatic group was more likely to have alterations in TP53, LRP1B, ERBB2 and MYC compared with DDR-germline group. Taken non-DDR group as reference, mutations in TP53 (P<0.05), ALK and PIK3CA were more common in DDR-germline group, but EGFR, RBM10, TP53, LRP1B, TERT and MYC (all P<0.05) in DDR-somatic group. Furthermore, the DDR-somatic group exhibits the highest median tumor mutational burden (6.56) compared with 3.55 (P<0.01) in DDR-germline and 3.69 (P<0.01) in non-DDR group. In addition, the copy number variation (CNV) was statistically different among the three groups (P<0.001). The proportion of copy number gain patients in DDR-somatic group is the highest (28.3%) compared with 12.0% in DDR-germline group and 10.9% in non-DDR group (P<0.01). DDR-somatic MPLC and SFLC patients possessed distinct somatic genomic characteristics, especially with significantly different prevalence in TP53, RBM10, KRAS, BRAF, and ALK (all P<0.05). Moreover, we also found notable differences in the prevalence of TP53 and CNV (both P<0.05) between DDR-germline MPLC and SFLC patients. Conclusions: MPLC patients exhibit a distinctive DDR mutations landscape. The differences in the mutation profile between the DDR-germline and DDR-somatic groups and the distinct actionable genes may indicate the different target-therapy choices for MPLC patients.

The characteristics and prognosis of different disease patterns of multiple primary lung cancers categorized according to the 8th edition lung cancer staging system.

The 8th edition lung cancer staging system was the first to describe the detailed diagnosis and staging of multiple primary lung cancers (MPLC). However, the characteristics and prognosis of MPLC categorized according to the new system have not been evaluated. We retrospectively analyzed data from surgically treated MPLC patients in a single center from 2011 to 2013 and explored the characteristics and outcomes of different MPLC disease patterns. In total, 202 surgically treated MPLC patients were identified and classified into different groups according to disease categories and diagnostic time (multifocal ground glass/lepidic (GG/L) nodules: n = 139, second primary lung cancer (SPLC): n = 63, simultaneous MPLC (sMPLC): n = 171, and metachronous MPLC (mMPLC): n = 31). There were significant differences in clinical characteristics between SPLC and GG/L nodule patients and simultaneous and metachronous MPLC patients. The overall 1-, 3-, and 5-year lung cancer-specific survival rates of MPLC were 97.98%, 90.18%, and 82.81%, respectively. Five-year survival was better in patients with multiple GG/L nodules than in those with SPLC (87.94% vs. 71.29%, P < 0.05). Sex was an independent prognostic factor for sMPLC (5-year survival, female vs. male, 88.0% vs. 69.5%, P < 0.05), and in multiple tumors, the highest tumor stage was an independent prognostic factor for all categories of MPLC. The different disease patterns of MPLC have significantly different characteristics and prognoses. Clinicians should place treatment emphasis on the tumor with the highest stage as it is the main contributor to the prognosis of all categories of MPLC patients.

The effect of spread through air spaces on postoperative recurrence-free survival in patients with multiple primary lung cancers

PurposeThe purpose of the study was to investigate the effect of spread through air spaces (STAS) on the postoperative prognosis of patients with multiple primary lung cancers staged from IA to IB based on tumor size.MethodsClinicopathological and follow-up data of 122 patients with multiple primary lung cancers diagnosed at stages IA-IB and surgically treated at the Department of Thoracic Surgery, Shenzhen people’s Hospital from January 2019 to December 2021 were retrospectively analyzed. The study involved 42 males and 80 females. STAS status was used to divide them into two groups (87 cases in STAS (-) and 35 cases in STAS (+)). A logistic regression analysis, univariate and multivariate Cox regression analysis, and Kaplan-Meier curves (K-M) were used to determine how STAS affected recurrence-free survival (RFS) in patients.ResultsSTAS (+) had a significantly higher recurrence rate than STAS (-). STAS was predicted by smoking history (P = 0.044), main tumor diameter (P = 0.02), and solid nodules on chest CT (P = 0.02). STAS incidence was not significantly different between lobectomy and sublobar resection groups (P = 0.17). Solid nodules on CT, tumor diameter, vascular invasion, pleural invasion, and STAS were significant predictors of recurrence in the univariate Cox regression analysis. Tumor diameter, pleural invasion and STAS were significant prognostic factors for recurrence in the multivariate Cox regression analysis. Furthermore, STAS (+) group was at greater risk of recurrence than STAS (-) group (34% vs. 0%, P < 0.05)。.ConclusionStage IA-IB multiple primary lung cancer patients with STAS (+) had a higher recurrence rate and a shorter overall survival rate.

Single-cell RNA sequencing analysis reveals transcriptional heterogeneity of multiple primary lung cancer.

With the advancements in early diagnosis, more and more patients with multiple primary lung cancer (MPLC) have been identified. However, the progression of MPLC involves complex changes in cell composition and metabolic function, which remains largely controversial. Our study aims to comprehensively reveal the cellular characteristics and inter-cellular connections of MPLC. We performed scRNA-seq from 23 samples of six MPLC patients, combined with bulk whole-exome sequencing. We performed trajectory analysis to investigate the transition of different cell types during the development of MPLC. A total of 167397 cells were sequenced derived from tumour and adjacent tissues of MPLC patients, and tumour, normal, immune and stromal cells were identified. Two states of epithelial cells were identified, which were associated with immune response and cell death, respectively. Furthermore, both CD8+ naïve and memory T cells participated in the differentiation of CD8+ T cells. The terminal states of CD8+ T cells were exhausted T cells and cytotoxic T cells, which positively regulated cell death and were implicated in the regulation of cytokine production, respectively. Two main subpopulations of B cells with distinct functions were identified, which participate in the regulation of the immune response and antigen presentation, respectively. In addition, we found a specific type of endothelial cells that were abundant in tumour samples, with an increasing trend from normal to tumour samples. Our study showed the comprehensive landscape of different cells of MPLC, which might reveal the key cellular mechanisms and, therefore, may provide new insights into the early diagnosis and treatment of MPLC.

Multiple Primary Lung Cancers: Treatment Outcomes After Stereotactic Body Radiotherapy (SBRT).

Patients with lung cancer sometimes present with multiple primary lung cancers (MPLCs), either simultaneously (synchronous) or after treatment of an initial lesion (metachronous). Although open surgery remains a treatment mainstay for patients with stage I-II non-small-cell lung cancer (NSCLC), stereotactic body radiation therapy (SBRT) is an acceptable alternative for patients who are medically unfit for or who refuse surgery. In this study, we retrospectively examine the outcome among patients with early-stage MPLCs treated at our institution with SBRT. Patients at our institution receiving SBRT for MPLC between June 2011 and March 2020 were reviewed retrospectively. Prior to undergoing definitive SBRT, the imaging, and pathology for every patient were reviewed in a multi-disciplinary thoracic/pulmonary tumor board. Dose and fractionation varied with the most common prescriptions being 50 Gy/5 fractions, 56 Gy/4 fractions, and 55 Gy/5 fractions. A total of 38 patients with a total of 80 MPLCs were treated, among which 68 were T1 lesions and 12 were T2 lesions. Median follow-up was 25.9 months, with local control (LC) rates calculated per lesion to be 98.6%, 93.3%, and 88.2% at one, two, and three years. Median overall survival (OS) was 43.5 months; 83.6%, 67.8%, and 52.3% at one, two, and three years, respectively. Sixty-two of the 80 (77.5%) treated lesions were not associated with any subsequent acute or late toxicity. The 18 (22.5%) lesions associated with toxicity included nine acute and nine late events. All toxicity was either grade 1 (13 of 18) or grade 2 (five of 18). SBRT for early-stage MPLC achieves high control rates with limited toxicity. MPLC patients deemed unfit for open surgical management should be considered for definitive SBRT.

Clinical diagnosis and treatment of multiple pulmonary nodules

CT screening has markedly reduced the lung cancer mortality in high-risk population and increased the detection of early-stage pulmonary neoplasms, including multiple pulmonary nodules, especially those with a ground-glass appearance on CT. Multiple primary lung cancer (MPLC) constitutes a specific subtype of lung cancer with indolent biological behaviors, which is predominantly early-stage adenocarcinoma. Although MPLC progresses slowly with rare lymphatic metastasis, existence of synchronous lesions and distributed location of these nodules still pose difficulty for the management of such patients. One single operation is usually insufficient to eradicate all neoplastic lesions, whereas repeated surgical procedures bring about another dilemma: whether clinical benefits of surgical treatment outweigh loss of pulmonary function following multiple operations. Therefore, despite the anxiety for treatment among MPLC patients, whether and how to treat the patient should be assessed meticulously. Currently there is a heated discussion upon the timing of clinical intervention, operation mode and the application of local therapy in MPLC. Based on clinical experience of our multiple disciplinary team, we have summarized and commented on the evaluation, surgical treatment, non-surgical local treatment, targeted therapy and immunotherapy of MPLC in this article to provide further insight into this field.

B4GALT1 promotes immune escape by regulating the expression of PD-L1 at multiple levels in lung adenocarcinoma

BackgroundInvasive adenocarcinoma (IAC), which is typically preceded by minimally invasive adenocarcinoma (MIA), is the dominant pathological subtype of early-stage lung adenocarcinoma (LUAD). Identifying the molecular events underlying the progression from MIA to IAC may provide a crucial perspective and boost the exploration of novel strategies for early-stage LUAD diagnosis and treatment.MethodsTranscriptome sequencing of four pairs of MIA and IAC tumours obtained from four multiple primary lung cancer patients was performed to screen out beta-1,4-galactosyltransferase1 (B4GALT1). Function and mechanism experiments in vitro and in vivo were performed to explore the regulatory mechanism of B4GALT1-mediated immune evasion by regulating programmed cell death ligand 1 (PD-L1).ResultsB4GALT1, a key gene involved in N-glycan biosynthesis, was highly expressed in IAC samples. Further experiments revealed that B4GALT1 regulated LUAD cell proliferation and invasion both in vitro and in vivo and was related to the impaired antitumour capacity of CD8 + T cells. Mechanistically, B4GALT1 directly mediates the N-linked glycosylation of PD-L1 protein, thus preventing PD-L1 degradation at the posttranscriptional level. In addition, B4GALT1 stabilized the TAZ protein via glycosylation, which activated CD274 at the transcriptional level. These factors lead to lung cancer immune escape. Importantly, inhibition of B4GALT1 increased CD8 + T-cell abundance and activity and enhanced the antitumour immunity of anti-PD-1 therapy in vivo.ConclusionB4GALT1 is a critical molecule in the development of early-stage LUAD and may be a novel target for LUAD intervention and immunotherapy.

Clinical and molecular characteristics of multiple primaries identified by whole-exome sequencing-based genetic divergence in non-small-cell lung cancer.

e20558 Background: With the recommendation of high-resolution chest computed tomography scan in lung cancer screening, multiple primary lung cancers (MPLC) is gaining more attention. Identifying MPLC from intrapulmonary metastases (IPM) is crucial to the clinical management. The current guidelines for the identification are always based on expert consensus rather than clinical evidence. We aim to develop a reliable identification method and further figure out the clinical and genetic features of MPLC. Methods: We retrospectively screened 305 lung lesions from 131 patients who underwent radical resection for multiple lung carcinomas. To minimize the effect of therapeutic intervention on prognostic outcomes, patients with each single tumor size smaller than 4cm, free of nodal or systemic metastases, and had high-quality whole-exon sequencing (WES) data were included. We selected 11 patients with confirmed intrapulmonary metastases for training. All patients’ follow-up information was collected until disease recurrence or metastases. A WES genetic divergence method for identifying MPLC from IPM was developed. The disease-free survival (DFS) was used as a validation tool for identification reliability. Results: A total of 61 eligible multi-lesion patients with 128 resected non-small cell lung cancer (NSCLC) lesions were finally analyzed. Based on WES genetic divergence identification, 51 MPLC patients were identified, whose DFS was significantly prolonged (HR, 0.27; 95% CI, 0.08 to 0.91; P = 0.02), while other recommended methods for identifying MPLC patients failed to show a DFS advantage. Among MPLC patients, 43.1% (22/51) had a first-degree relatives cancer family history, of whom 54.5% (12/22) had a lung cancer family history. EGFR was still the most common mutation gene (72.5%, 37/51); however, TP53 mutations was less frequent in MPLC (21% vs. 48%, P &lt; 0.05), and tumor mutation burden (TMB) was lower (median, 0.73 muts/Mb vs. 1.15 muts/Mb, P &lt; 0.01). Notably, despite the lack of shared alterations, unique germline variants in cancer-predisposing genes, particularly nonsynonymous SNV in solute carrier gene (SLC) family, were observed in most MPLC patients, rarely overlapping with IPM patients. Conclusions: WES-based genetic divergence clearly distinguishes independent primary tumors from IPM in NSCLC patients. MPLC patients represent a unique population which deserves further study.

High frequency of germline mutations in DDR associated genes SLX4, MSH6, CDK4, TSC2, and BRCA2 might contribute to the occurrence of MPLC.

e20514 Background: Multiple primary lung cancer (MPLC) is the presence of two or more distinct and separate lung tumors in a single patient. Each is considered a primary tumor rather than a metastasis from another site. This phenomenon has been the subject of several studies in recent years due to its increasing incidence and potential implications for patient management and prognosis. The underlying causes of MPLCs are not fully understood. Still, several factors have been proposed to contribute, including the genetic predisposition of carcinogens, such as those in the TP53, BRCA1, and BRCA2 genes, which are associated with an increased risk of developing MPLCs, as well as other cancers. Whether the presence of germline genetic mutations can increase an individual's susceptibility and contribute to the development of MPLCs is not clear yet. Here we reported the landscape of germline mutations of 77 MPLC patients. Methods: We retrospectively analyzed the somatic and germline mutations from 77 MPLC patients by NGS analysis. The GO and KEGG analyses were performed based on the top 30 most frequent germline mutations. Results: Among the 77 patients, 21 (27.27%) were male, and 56 (72.73%) were female. The median age was 60 (26-82) years old. The top 5 frequent germline mutated genes were SLX4 (34.92%), MSH6 (39.68%), CDK4 (26.98%), TSC2 (25.4%), and BRCA2 (25.4%). The top 5 frequent somatic mutated genes were EGFR (80.95%), CDK4 (26.98%), MCL1 (23.81%), SOCS1 (19.05%), and TP53 (19.05%). GO analysis of germline mutations revealed enrichment in ontologies such as response to radiation and UV, cell cycle regulation, a series of DNA damage repair associated ontologies, and telomere organization. KEGG analysis indicated that these germline mutations were enriched in the PI3K-Akt pathway, microRNAs in cancer, TP53 pathway, Fanconi anemia pathway, cellular senescence, and many other cancer-associated pathways. Conclusions: Germline alterations in many genes coding for proteins regulating DNA repair and DNA damage response (DDR) to DNA double-strand breaks (DDSB) have been recognized as pathogenic factors in hereditary cancer predisposition. In our analysis, the MPLC patients contained widespread germline mutations in SLX4, MSH6, CDK4, TSC2, and BRCA2, which were all associated with DNA damage repair. Besides, GO analysis and KEGG analysis also revealed enrichment in DDR-associated ontologies or pathways (e.g., TP53 pathway, Fanconi anemia pathway, cellular senescence pathways). To our knowledge, an underlying hallmark of cancers is their genomic instability, which is associated with a greater propensity to accumulate DNA damage. The widespread of germline mutations in DDR-associated genes, including SLX4, MSH6, CDK4, TSC2, and BRCA2, might contribute to the gene instability and promote the development of MPLC.

Comprehensive genetic characteristics of multiple primary lung cancer in patients in China.

e20597 Background: With the development of molecular biology and next-generation sequencing (NGS), researchers have been exploring the use of genomic technologies for the classification of lung cancers. The aim of this study was to investigate genetic characteristics of multiple primary lung cancer (MPLC) to facilitate precise diagnosis and therapy by NGS. Methods: A total of 271 lesions from 92 patients with MPLC (225 lesions) and 20 intrapulmonary metastasis (IM, 46 lesions) which were diagnosed by American College of Chest Physicians (ACCP) guidelines, were sequenced by Acornmed panel with 808 cancer-related genes. Results: The most frequent mutation in 225 lesions was EGFR (46.7%), followed by RBM10 (19.6%), BRAF (16.4%) and KRAS (15.1%) among MPLC while IM lesions showed high TP53 (63.0%) mutation frequency. Further analysis showed that MPLC patients had higher proportion of private mutations, and lower proportion of shared mutations and branch shared mutations than IM (p &lt; 0.0001). In our cohort, 95.7% (88/92) of MPLC patients had at least one driver alteration, and EGFR and KRAS comprised 57.4% and 18.0% of 183 driver mutations, respectively. Further analysis showed that only 19.6% (18/92) of MPLC shared the same driver mutation in each patient and 61.1% (11/18) of co-driver mutation was EGFR L858R which was commonly detected in lung cancer. In contrast, 95.0% (19/20) of IM shared the same driver mutation in each patient. MPLCs were associated with a high frequency of T &gt; C transitions (p &lt; 0.001), while T &gt; G transversions (p &lt; 0.001) were more frequent in tumors from IM. MPLC had significantly higher intratumor heterogeneity (ITH) (17.1 vs 4.05, p &lt; 0.001) and lower weighted-genomic integrity index (wGII) than IM (0.01638 vs 0.18321, p &lt; 0.001). Besides, MPLC had lower percentage of clonal mutations (p &lt; 0.001) than IM. However, IM had higher arm-level somatic copy number variations fraction (p &lt; 0.001) than MPLC. Conclusions: Our analysis reveals that patients with MPLC have distinct molecular characteristics different from IM, which may increase the understanding of MPLC. In addition, the molecular features of MPLC may provide new opportunities to distinguish MPLC from IM by broad panel NGS.

Somatic aberrations detected in tumor tissue and plasma in Chinese patients with stage I single-lesion and multi-lesions lung cancer.

e20600 Background: Recent studies show that the use of circulating tumor DNA (ctDNA) has potential to guide precision medicine and transform the management of early-stage lung cancers. We aim to investigate whether plasma is suitable for detecting tumor‐derived DNA in patients with stage I single-lesion lung cancer and multifocal lung cancer which has rarely been investigated. Methods: Matched tumor tissues (n = 114) and plasma samples (n = 95) from Chinese patients with stage I lung cancer (n = 95), including 80 patients with single-lesion and 15 patients with multiple primary lung cancer (MPLC) diagnosed by American College of Chest Physicians (ACCP) guidelines, were analyzed by Acornmed panel with 808 cancer-related genes. Results: Using tumor tissue-based results as the gold standard, we performed variant-level assessment of the ctDNA tests. In patients with single-lesion, sequencing detected alterations in 98.8% (79/80) ctDNA and 9.3% (74/797) of variants in ctDNA were detected by corresponding tDNA. Among them, 31.3% (25/80) patients had at least one overlapping variant called by tDNA and ctDNA, and 5% (4/80) patients shared EGFR in both tDNA and ctDNA. Meanwhile, we identified 2 mutated EGFR in ctDNA that were not detected in tissues. As for multiple primary lung cancers, 86.7% (13/15) of MPLC patients had ≥1 alteration in ctDNA. In addition, 7.4% (9/122) of variants in ctDNA were detected by corresponding tDNA in MPLC. The overall concordance for all variants detected in both ctDNA and any tDNA of patients was 53.3% (8/15) in MPLC, with EGFR and KRAS as the most two frequent mutations. Furthermore, mutations consistent with ctDNA were detected in 29.4% (10/34) of the lesions in MPLC. Conclusions: Our analysis showed that plasma with high mutation detection rate and considerable concordance rate with tDNA maybe a powerful complement to tissues for molecular testing in lung cancer. Furthermore, ctDNA detection not only may be able to overcome the heterogeneity of tumors but also more comprehensively reflect the disease state of patients with multifocal lung cancer.

Multiple primary lung cancer: Updates of clinical management and genomic features.

In recent decades, multiple primary lung cancer (MPLC) has been increasingly prevalent in clinical practice. However, many details about MPLC have not been completely settled, such as understanding the driving force, clinical management, pathological mechanisms, and genomic architectures of this disease. From the perspective of diagnosis and treatment, distinguishing MPLC from lung cancer intrapulmonary metastasis (IPM) has been a clinical hotpot for years. Besides, compared to patients with single lung lesion, the treatment for MPLC patients is more individualized, and non-operative therapies, such as ablation and stereotactic ablative radiotherapy (SABR), are prevailing. The emergence of next-generation sequencing has fueled a wave of research about the molecular features of MPLC and advanced the NCCN guidelines. In this review, we generalized the latest updates on MPLC from definition, etiology and epidemiology, clinical management, and genomic updates. We summarized the different perspectives and aimed to offer novel insights into the management of MPLC.

Comparison of stereotactic body radiation therapy versus surgery for multiple primary lung cancers after prior radical resection: A multicenter retrospective study

BackgroundPatients who previously underwent surgical resection of initial primary lung cancer are at a high risk of developing multiple primary lung cancers (MPLCs). The purpose of this study was to compare the efficacy and safety between stereotactic body radiation therapy (SBRT) and surgery for MPLCs patients after prior radical resection for the first lung cancers. MethodsIn this multicenter retrospective study, eligible MPLC patients with tumor diameter of 5.0 cm or less at N0M0 who underwent SBRT or reoperation between January 2013 and August 2020 were enrolled. The primary endpoint was the 3-year locoregional recurrence and treatment-related toxicity. Kaplan-Meier method was used to calculate survival rates. The χ2 test was adapted to assess the difference of categorical variables between the two subgroup patients. ResultsA total of 203 (73 in the SBRT group and 130 in the surgery group) patients from three academic cancer centers were evaluated with a median follow-up of 38.3 months. The cumulative 1-, 2-, and 3-year incidences of locoregional recurrence were 5.6 %, 7.0 % and 13.1 % in the SBRT group versus 3.2 %, 4.8 % and 7.4 % in the surgery group, respectively [hazard ratio (HR), 1.97; 95 % confidence interval (CI), 0.74–5.24; P = 0.14]. The cancer-specific survival rates were 95.9 %, 94.5 % and 88.1 % versus 96.9 %, 94.6 % and 93.8 % in the SBRT and surgery groups respectively (HR, 1.72; 95 % CI, 0.67–4.44; P = 0.23). In the SBRT group, two patients (2.7 %) suffered from grade 3 radiation pneumonitis, while in the surgery group, grade 3 complications occurred in four (3.1 %) patients, and four cases were expired due to pneumonia or pulmonary heart disease within 90 days after surgery. ConclusionsSBRT is an effective therapeutic option with limited toxicity compared to surgery for patients with MPLCs after prior radical surgical resection, and it could be considered as an alternative treatment for those patients.

Lack of evolutionary convergence in multiple primary lung cancer suggests insufficient specificity of personalized therapy

Multiple primary lung cancer (MPLC) is an increasingly prevalent subtype of lung cancer. According to recent genomic studies, the different lesions of a single MPLC patient exhibit functional similarities that may reflect evolutionary convergence. We perform whole-exome sequencing for a unique cohort of MPLC patients with multiple samples from each lesion found. Using our own and other relevant public data, evolutionary tree reconstruction reveals that cancer driver gene mutations occurred at the early trunk, indicating evolutionary contingency rather than adaptive convergence. Additionally, tumors from the same MPLC patient are as genetically diverse as those from different patients, while within-tumor genetic heterogeneity is significantly lower. Furthermore, the aberrant molecular functions enriched in mutated genes for a sample show a strong overlap with other samples from the same tumor, but not with samples from other tumors or other patients. Overall, there is no evidence of adaptive convergence during the evolution of MPLC. Most importantly, the similar between-tumor diversity and between-patient diversity suggest that personalized therapies may not adequately account for the genetic diversity among different tumors in an MPLC patient. To fully exploit the strategic value of precision medicine, targeted therapies should be designed and delivered on a per-lesion basis.

EP01.01-012 Clinical and Molecular Features of Chinese Early-stage Multiple Primary Lung Cancer Patients

The incidence of early-stage multiple primary lung cancer (MPLC) has been increasing in recent years, while the ideal strategy for its diagnosis and treatment remains controversial. Moreover, the difference between MPLC and intrapulmonary metastasis (IM) in patients with lung cancer is vital but controversial.

Progress in clinical diagnosis and treatment of multiple primary lung cancer

With the application of high-resolution chest imaging system and lung cancer screening program, patients with multiple primary lung cancer (MPLC) are becoming a growing population in clinical practice. However, the diagnostic criteria of MPLC and its differentiation from intrapulmonary metastasis of lung cancer (IM) are still controversial, especially in cases with similar histology. On the basis of reviewing the existing literature, this paper discusses the changes of the diagnostic criteria of MPLC and the differential diagnosis methods of imaging, histology and molecular genetics of MPLC and IM, and briefly introduces the application of multidisciplinary diagnosis, algorithm, predictive model and artificial intelligence in the differential diagnosis of MPLC. In addition, we also discuss the latest progress in the treatment of MPLC. Radical surgery is the main method for the treatment of MPLC. Stereotactic body radiation therapy (SBRT) is safe and feasible for inoperable MPLC patients, and targeted therapy and immunotherapy can also be used in MPLC after appropriate patient selection.

Clinical and genetic characteristics of early-stage multiple primary and independent primary lung adenocarcinoma patients.

The difference between multiple primary lung cancers (MPLC) and intrapulmonary metastasis (IM) in patients with lung cancer is vital but controversial. Moreover, the genetic and clinical significance difference between MPLC and independent primary lung cancers (IPLC) patients is unknown. This study retrospectively researched clinical and genetic data of MPLC and IPLC patients from January 2019 to May 2021 at the affiliated hospital of Qingdao University, China. Ninety-four tissue samples from 41 early-stage patients with MPLC, and 94 tissue samples from 94 early-stage patients with IPLC were performed to targeted sequencing. A total of 36 patients (88%) showed inconsistent driver mutations, and five MPLC patients (12%) shared single identical EGFR/BRAF/TP53 hotspot mutations in the early stage. In MPLC patients, high-frequency mutations included EGFR (63%), TP53 (12%), BRAF (12%), KRAS (10%), ERBB2 (4%), PIK3CA (3%), and MET (3%). In IPLC patients, high-frequency mutations included EGFR (55%), TP53(26%), KRAS (13%), MAP2K1 (5%), PIK3CA (4%), ERBB2 (4%), NF1 (4%), RET (3%), and BRAF (2%). The higher BRAF and fewer TP53 mutations may be related to the lower malignancy in MPLC patients. The accuracy of pathological diagnosis in patients with early-stage MPLC does not need comprehensive molecular evaluation to supplement histology for differentiating early-stage MPLC and IM. Meanwhile, the molecular difference between MPLC and IPLC may be helpful to study the mechanism of MPLC pathogenesis.

Genetic and immune characteristics of multiple primary lung cancers and lung metastases.

BackgroundTo explore the genetic and immunophenotyping heterogeneities between patients with intrapulmonary metastasis (IPM) or multiple primary lung cancer (MPLC).MethodsWhole exome sequencing (WES) and transcriptome sequencing (RNA‐seq) were performed on the tissue and blood samples of IPM and MPLC patients to comprehensively analyze the clonal evolution, molecular typing and immunophenotyping.ResultsThere was no significant difference in genetic mutation, tumor mutational burden (TMB) value and mutant allele tumor heterogeneity (MATH) value between IPM and MPLC patients. Notably, the loss of heterozygosity (LOH) of human leukocyte antigen (HLA) appeared in all IPM patients, while there was also no significant difference between the two groups. In addition, expression of immune checkpoint‐related genes including CTLA‐4, BTLA, TIGIT and HAVCR2 in the MPLC group was significantly higher than those in IPM group. At the same time, 86 differentially expressed genes (DEGs) were observed between IPM and MPLC patients with transcriptome sequencing, of which 56 DEGs were upregulated and 30 were downregulated in the IPM group compared with the MPLC group. The cluster analysis revealed that the 86 DEGs could be distinguished in IPM and MPLC samples. Moreover, only the infiltration levels of CD56dim natural killer cells in the IPM group was significantly higher than that in the MPLC group, and the infiltration levels of the remaining 27 immune cell subsets were similar in both groups.ConclusionsIPM and MPLC are roughly similar in genetic and immune characteristics indicating that genomics alone may not be able to effectively distinguish between IPM and MPLC, which still needs to be comprehensively evaluated with clinical manifestations, imaging, and pathological characteristics.

Molecular Identification and Genetic Characterization of Early-Stage Multiple Primary Lung Cancer by Large-Panel Next-Generation Sequencing Analysis.

ObjectiveThe incidence of early stage multiple primary lung cancer (MPLC) has been increasing in recent years, while the ideal strategy for its diagnosis and treatment remains controversial. The present study conducted genomic analysis to identify a new molecular classification method for accurately predicting the diagnosis and therapy for patients with early stage MPLC.MethodsA total of 240 tissue samples from 203 patients with multiple-non-small-cell lung cancers (NSCLCs) (n = 30), early stage single-NSCLC (Group A, n = 94), and advanced-stage NSCLC (Group B, n = 79) were subjected to targeted multigene panel sequencing.ResultsThirty patients for whom next-generation sequencing was performed on >1 tumor were identified, yielding 45 tumor pairs. The frequencies of EGFR, TP53, RBM10, ERBB2, and CDKN2A mutations exhibited significant differences between early and advanced-stage NSCLCs. The prevalence of the EGFR L858R mutation in early stage NSCLC was remarkably higher than that in advanced-stage NSCLC (P = 0.047). The molecular method classified tumor pairs into 26 definite MPLC tumors and four intrapulmonary metastasis (IM) tumors. A high rate of discordance in driver genetic alterations was found in the different tumor lesions of MPLC patients. The prospective Martini histologic prediction of MPLC was discordant with the molecular method for three patients (16.7%), particularly in the prediction of IM (91.7% discordant).ConclusionsComprehensive molecular evaluation allows the unambiguous delineation of clonal relationships among tumors. In comparison, the Martini and Melamed criteria have notable limitations in the recognition of IM. Our results support the adoption of a large panel to supplement histology for strongly discriminating NSCLC clonal relationships in clinical practice.

Characteristic of genetic and t cell receptor repertoire of Chinese multiple primary lung cancer patients.

e20510 Background: As the incidence of lung cancer soars, the number of patients diagnosed with multiple primary lung cancers (MPLC) was also rising. It was already known that genetic and immune microenvironment were involved in oncogenesis and treatment of tumors. The aim of this study was to investigate genetic and T Cell Receptor (TCR) Repertoire characteristic in patients with multiple primary lung cancers. Methods: We queried 84 lesions analyzed by 1021 gene panel and TCRβ repertoire for 32 patients with MPLC profiled by NGS. Shannon index was calculated on the clonal abundance of all productive TCR sequences. T cell clonality was defined as 1 − (Shannon index)/ln(# of productive unique sequences). MOI was a measure of the similarity in the T cell repertoire between tissue and blood taking into account the specific rearrangements and their respective frequencies. Results: 98.7% (77/78) of lesions from 30 patients were detected somatic mutations and EGFR mutations were detected in 44.2% (34/77) lesions; BRAF were detected in 22.1% (17/77) lesions; and KRAS were detected in 14.3% (11/77) lesions. We found different combinations of three driving genes in 13 patients. Almost all lesions (97.4%) had mutations in the RAS-RTK pathway. Shared mutations were detected between different lesions from 8 patients, and two patients were intrapulmonary metastases; The others were more meet to convergent evolution. The overall immune characteristics of 76 lesions from 30 patients were further studied. The shannon index showed heterogeneity in difference lesions of each patients and the comparing the most and least shannon index lesions variations ranged between 0.066 to 3.344. The lesions with shared mutations showed higher Shannon index than the non-share lesions (7.31 vs 6.96; p = 0.011). The heterogeneity also identified in MOI and 55% MOI of lesions was less than 0.5. The lesions with MOI higher than 0.5 had some pathologically identical and some have shared mutations. Furthermore, the shared TCR between lesions in same patient were analyzed. The more than 78% of T cell clones were restricted to individual lesions, which indicated the presence of heterogeneity between lesions due to T cell clones distribution heterogeneity. Meanwhile, the shared TCR was significantly higher in identical pathology group than difference pathology group (17.18% vs 6.60%; p = 0.0006); Besides, we found that shared TCR was comparable in both shared mutations and non-shared mutations groups (13.1% vs 15.33%, p = 0.537). These results suggested that the pathology between lesions in patients was affected to 100% shared TCR. Conclusions: In conclusion, the multiple lesions of MPLC showed heterogeneity and this heterogeneity is due to the distribution of T cell clones between lesions. Besides, the MOI and shared TCR was higher in MPLC with same pathology, which may increase the understanding of MPLC and influence the treatment choice of MPLC patients.