Dosimetric comparison of IMPT vs VMAT for multiple lung lesions: an NTCP model-based decision-making strategy.

To compare the dosimetric differences in volumetric modulated arc therapy (VMAT) and intensity modulated proton therapy (IMPT) in stereotactic body radiation therapy (SBRT) of multiple lung lesions and determine a normal tissue complication probability (NTCP) model-based decision strategy that determines which treatment modality the patient will use. A total of 41 patients were retrospectively selected for this study. The number of patients with 1-6 lesions was 5, 16, 7, 6, 3, and 4, respectively. A prescription dose of 70 GyRBE in 10 fractions was given to each lesion. SBRT plans were generated using VMAT and IMPT. All the IMPT plans used robustness optimization with ± 3.5% range uncertainties and 5 mm setup uncertainties. Dosimetric metrics and the predicted NTCP value of radiation pneumonitis (RP), esophagitis, and pericarditis were analyzed to evaluate the potential clinical benefits between different planning groups. In addition, a threshold for the ratio of PTV to lungs (%) to determine whether a patient would benefit highly from IMPT was determined using receiver operating characteristic curves. All plans reached target coverage (V70GyRBE ≥ 95%). Compared with VMAT, IMPT resulted in a significantly lower dose of most thoracic normal tissues. For the 1-2, 3-4 and 5-6 lesion groups, the lung V5 was 29.90 ± 9.44%, 58.33 ± 13.35%, and 81.02 ± 5.91% for VMAT and 11.34 ± 3.11% (p < 0.001), 21.45 ± 3.80% (p < 0.001), and 32.48 ± 4.90% (p < 0.001) for IMPT, respectively. The lung V20 was 12.07 ± 4.94%, 25.57 ± 6.54%, and 43.99 ± 11.83% for VMAT and 6.76 ± 1.80% (p < 0.001), 13.14 ± 2.27% (p < 0.01), and 19.62 ± 3.48% (p < 0.01) for IMPT. The Dmean of the total lung was 7.65 ± 2.47 GyRBE, 14.78 ± 2.75 GyRBE, and 21.64 ± 4.07 GyRBE for VMAT and 3.69 ± 1.04 GyRBE (p < 0.001), 7.13 ± 1.41 GyRBE (p < 0.001), and 10.69 ± 1.81 GyRBE (p < 0.001) for IMPT. Additionally, in the VMAT group, the maximum NTCP value of radiation pneumonitis was 73.91%, whereas it was significantly lower in the IMPT group at 10.73%. The accuracy of our NTCP model-based decision model, which combines the number of lesions and PTV/Lungs (%), was 97.6%. The study demonstrated that the IMPT SBRT for multiple lung lesions had satisfactory dosimetry results, even when the number of lesions reached 6. The NTCP model-based decision strategy presented in our study could serve as an effective tool in clinical practice, aiding in the selection of the optimal treatment modality between VMAT and IMPT.

Lineage tracing for multiple lung cancer by spatiotemporal heterogeneity using a multi-omics analysis method integrating genomic, transcriptomic, and immune-related features.

Introduction: The distinction between multiple primary lung cancer (MPLC) and intrapulmonary metastasis (IPM) holds clinical significance in staging, therapeutic intervention, and prognosis assessment for multiple lung cancer. Lineage tracing by clinicopathologic features alone remains a clinical challenge; thus, we aimed to develop a multi-omics analysis method delineating spatiotemporal heterogeneity based on tumor genomic profiling. Methods: Between 2012 and 2022, 11 specimens were collected from two patients diagnosed with multiple lung cancer (LU1 and LU2) with synchronous/metachronous tumors. A novel multi-omics analysis method based on whole-exome sequencing, transcriptome sequencing (RNA-Seq), and tumor neoantigen prediction was developed to define the lineage. Traditional clinicopathologic reviews and an imaging-based algorithm were performed to verify the results. Results: Seven tissue biopsies were collected from LU1. The multi-omics analysis method demonstrated that three synchronous tumors observed in 2018 (LU1B/C/D) had strong molecular heterogeneity, various RNA expression and immune microenvironment characteristics, and unique neoantigens. These results suggested that LU1B, LU1C, and LU1D were MPLC, consistent with traditional lineage tracing approaches. The high mutational landscape similarity score (75.1%), similar RNA expression features, and considerable shared neoantigens (n = 241) revealed the IPM relationship between LU1F and LU1G which were two samples detected simultaneously in 2021. Although the multi-omics analysis method aligned with the imaging-based algorithm, pathology and clinicopathologic approaches suggested MPLC owing to different histological types of LU1F/G. Moreover, controversial lineage or misclassification of LU2's synchronous/metachronous samples (LU2B/D and LU2C/E) traced by traditional approaches might be corrected by the multi-omics analysis method. Spatiotemporal heterogeneity profiled by the multi-omics analysis method suggested that LU2D possibly had the same lineage as LU2B (similarity score, 12.9%; shared neoantigens, n = 71); gefitinib treatment and EGFR, TP53, and RB1 mutations suggested the possibility that LU2E might result from histology transformation of LU2C despite the lack of LU2C biopsy and its histology. By contrast, histological interpretation was indeterminate for LU2D, and LU2E was defined as a primary or progression lesion of LU2C by histological, clinicopathologic, or imaging-based approaches. Conclusion: This novel multi-omics analysis method improves the accuracy of lineage tracing by tracking the spatiotemporal heterogeneity of serial samples. Further validation is required for its clinical application in accurate diagnosis, disease management, and improving prognosis.

The Unique Genetic Mutation Characteristics Based on Large Panel Next-Generation Sequencing (NGS) Detection in Multiple Primary Lung Cancers (MPLC) Patients.

BACKGROUND: With the wide application of multislice spiral computed tomography (CT), the frequency of detection of multiple lung cancer is increasing. This study aimed to analyze gene mutations characteristics in multiple primary lung cancers (MPLC) using large panel next-generation sequencing (NGS) assays. METHODS: Patients with MPLC surgically removed from the Affiliated Hospital of Guangdong Medical University from Jan 2020 to Dec 2021 enrolled the study. NGS sequencing of large panels of 425 tumor-associated genes was performed. RESULTS: The 425 panel sequencing of 114 nodules in 36 patients showed that epidermal growth factor receptor (EGFR) accounted for the largest proportion (55.3%), followed by Erb-B2 Receptor Tyrosine Kinase 2 (ERBB2) (9.6%), v-Raf murine sarcoma viral oncogene homolog B1 (BRAF), and Kirsten rat sarcoma viral oncogene (KRAS) (8.8%). Fusion target variation was rare (only 2, 1.8%). ERBB2 Y772_A775dup accounted for 73%, KRAS G12C for about 18%, and BRAF V600E for only 10%. AT-rich interaction domain 1A (ARID1A) mutations were significantly higher in invasive adenocarcinoma (IA) which contained solid/micro-papillary malignant components (p = 0.008). The tumor mutation burden (TMB) distribution was low, with a median TMB of 1.1 MUTS/Mb. There were no differences in the TMB distribution of different driver genes. In addition, 97.2% of MPLC patients (35/36) had driver gene mutations, and 47% had co-mutations, mainly in IA (45%) and invasive adenocarcinoma (MIA) (37%) nodule, with EGFR (39.4%), KRAS (9.1%), ERBB2 (6.1%), tumor protein 53 (TP53) (6.1%) predominately. CONCLUSIONS: MPLC has a unique genetic mutation characteristic that differs from advanced patients and usually presents with low TMB. Comprehensive NGS helps to diagnose MPLC and guides the MPLC clinical treatment. ARID1A is significantly enriched in IA nodules containing micro-papillary/solid components, suggesting that these MPLC patients may have a poor prognosis.

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

Background: The ability to distinguish satellite nodules, multiple primary lung cancers (MPLCs), and intrapulmonary metastases (IPM) is crucial for prognosis and treatment. The traditional diagnostic criteria for MPLC/IPM including the Martini and Melamed (MM) criteria and the comprehensive histologic assessment (CHA) criteria, mainly relies on histological comparison between multiple lesions. However, many challenges remain in distinguishing them in clinical practice. Case Description: We herein present a report of 3 lung adenocarcinoma cases who presented with 2 lesions, with improved diagnosis based on targeted sequencing covering driver genes. Based on histopathological features, patient 1 (P1) was classified as MPLC, whereas patients 2 and 3 (P2, P3) were classified as satellite nodules. However, targeted sequencing revealed the clonality status of these lesions and improved their diagnosis. The result of the molecular testing indicated that P1 is IPM and the other two patients (P2, P3) should be diagnosed with MPLC. Conclusions: Different lesions in the same case had different driver mutations, suggesting that the 2 lesions were driven by different molecular events. Therefore, targeted sequencing containing driver genes should be used for the diagnosis of multiple synchronous lung cancers. A limitation of this report is the short follow up period, and long-term outcomes of the patients require further follow up.

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.

Multiple primary lung cancer comprised of adenocarcinoma and adenoid cystic carcinoma: a case report.

Background: Multiple primary lung cancer (MPLC) is a rare type of tumor, and it is necessary to differentiate it from a metastatic tumor. The type of adenocarcinoma with adenoid cystic carcinoma (ACC) is extremely rare and has not yet been reported in the literature. The initial clinical symptoms of double primary lung cancer may be nonspecific; hence, the diagnosis is often missed or incorrect. Case Description: In this case presentation, we report the case of a 67-year-old female who had experienced persistent cough and expectoration for 8 days. Chest computed tomography (CT) revealed 2 nodules in the patient's lung. Radiographic findings could not distinguish between the 2 nodules and between primary and metastatic lesions. Thus, the patient underwent bronchoscopic biopsy and percutaneous lung puncture. We could not determine the type of the two tumors in hematoxylin and eosin (H&E) staining sections, and we subsequently performed specific immunohistochemical (IHC) staining. Combined with morphological and IHC results, we concluded that this was a case of MPLC, consisting of adenocarcinoma and ACC. The patient received symptomatic treatment because of the metastases. Conclusions: This report reports a rare combination of MPLC and shows that a definitive diagnosis of double primary lung cancer can be based on tissue biopsy and IHC techniques.

Presentation of EGFR mutations in 162 family probands with multiple primary lung cancer.

BACKGROUND: The number of multiple primary lung cancer (MPLC) patients has rapidly increased in recent years. However, information regarding the etiology of MPLC and responsiveness to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) is rare. The present study aims to describe the mutation signatures of EGFR in MPLC. METHODS: Polymerase chain reaction (PCR) and Sanger sequencing were used to screen EGFR mutations in 162 family probands comprising 366 tumor lesions and 162 paired noncancerous adjacent tissues (NATs). Sequencing data from 3,243 sporadic lung adenocarcinoma (LUAD) samples were analyzed as a control. RESULTS: Candidate germline mutations were observed in exons 19 (3, 1.85%), 20 (8, 4.94%) and 21 (5, 3.10%), with a total frequency of 9.88% in NATs (16/162). There were 63 probands harboring somatic mutations (63/162, 38.89%), 9 patients harbored the consistency mutations among lesions, and 8 patients carried 2 or more mutations. The overall rate of EGFR somatic mutations was lower in the MPLC probands, but those of exon 19 p.747-752del, 20 p.V769indelsVASV and 20 p.D770indelsDSVD were significantly higher in MPLC probands than in patients with sporadic LUAD. CONCLUSIONS: There exists unique EGFR mutation signatures in a large cohort of MPLC probands, which might provide objective evidence of the etiology and effectiveness of clinical TKI treatment of high-risk MPLC patients.

Tailing effect of PD-1 antibody results in the eradication of unresectable multiple primary lung cancer presenting as ground-glass opacities: a case report.

There is currently no standard treatment for multiple primary lung cancer (MPLC). We report a case of synchronous MPLC presenting as one ground-glass opacity (GGO) with predominant consolidation accompanied by at least parietal pleura involvement, and another with >30 GGOs distributed across bilateral lungs, which was ineligible for complete resection. CT-guided percutaneous biopsy of the nearly pure-solid mass showed invasive lung adenocarcinoma mainly composed of acinar type. Capture-based, ultra-deep targeted sequencing (Burning Rock, Guangzhou, China) was performed on the tumor tissue biopsy. The result revealed no druggable mutations according to the guideline and a high TMB of 34.1 Mb. Immunohistochemical staining (22C3; Dako, Denmark) was positive for PD-L1 expression with a tumor expression level of 30%. Based on the clinical information and patient's decision, he received 3 cycles of pemetrexed plus pembrolizumab and was subsequently forced to withdraw due to acquired immune-related pneumonitis. After discontinuation of corticosteroids, he was subjected to wedge resection for the nearly pure-solid lesion, and then refused further treatment for the other tumors. After a follow-up of 12 months from termination of immunotherapy, almost all GGOs achieved radiographically complete remission, attributed to the tailing effect of the programmed cell death protein 1 (PD-1) antibody of pembrolizumab. Through the case study we found that unresectable synchronous MPLC presenting as GGOs may respond well to immunotherapy.

Coexistence of atypical adenomatous hyperplasia, minimally invasive adenocarcinoma and invasive adenocarcinoma: Gene mutation analysis.

Multiple primary lung cancer (MPLC) refers to the simultaneous occurrence of two or more lung primary malignant tumors in one individual. The detection rate of MPLC has increased significantly in recent years, and the distinction between MPLC and lung metastasis has strong clinical significance. Whole exome sequencing (WES) can clearly identify the heterogeneity between MPLC nodules. Here, we report a case of a 50-year-old Asian female without a history of smoking. She underwent a lung computed tomography (CT) scan and three ground-glass nodules (GGNs) were found which were pathologically confirmed as atypical adenomatous hyperplasia (AAH), minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IA), respectively. We performed WES on the three pulmonary nodules and analyzed the sequencing results. We believe that this is the first published report of a case of "three phases" of lung adenocarcinoma analyzed by WES. Under the same genetic background and internal environment, these three nodules showed significant genetic differences and developed into "three phases" of lung adenocarcinoma. Analysis of the WES results supported the lung adenocarcinoma model from AAH to MIA and IA, and explored possible potential driver genes and therapeutic targets. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: We used WES to analyze the gene mutation status of three tumors in one individual. We found that even if under the same genetic background, AAH, MIA and IA showed significant genetic differences and developed into "three phases" of lung adenocarcinoma. WHAT THIS STUDY ADDS: Analysis of the WES results supported the lung adenocarcinoma model from AAH to MIA and IA, and explored possible potential driver genes and therapeutic targets.

Imaging of synchronous multiple primary lung adenocarcinoma with concomitant EGFR and KRAS mutations: a case report and review of the literature.

With the application of computed tomography (CT) imaging technology, the incidence rate of multiple primary lung cancer has gradually increased. However, the prevalence of concomitant epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene (KRAS) mutations in patients with non-small cell lung cancer (NSCLC) is low, and cases of concomitant EGFR and KRAS mutations have rarely been reported. In this case, we report a 71-year-old male patient with multiple primary lung adenocarcinoma harboring different gene mutation subtypes of KRAS and EGFR. The lesions in different lung lobes had distinct imaging features. One lesion was a solid mass in the upper lobe of the left lung, and the other was a cyst-like lung adenocarcinoma in the upper lobe of the right lung. Laboratory tests were positive for the marker carcinoembryonic antigen (CEA). The patient underwent thoracoscopic resection of the bilateral lung lesions, received chemotherapy and immunosuppressant therapy and exhibited progression-free survival (PFS) for 1 year. Later, the patient developed mediastinal lymph node and brain metastasis and died of multiple metastases. It is important to note that lung lesions with distinct imaging features may be associated with different types of gene mutations. Prediction of the gene mutation phenotype of lesions based on differences in imaging features and the biological behavior of genes, including the coexistence of EGFR and KRAS mutations, will undoubtedly assist the clinical development of individualized diagnosis and treatment planning.

A comprehensive algorithm to distinguish between MPLC and IPM in multiple lung tumors patients.

BACKGROUND: Diagnosis of multiple lung nodules has become convenient and frequent due to the improvement of computed tomography (CT) scans. However, to distinguish intrapulmonary metastasis (IPM) from multiple primary lung cancer (MPLC) remains challenging. Herein, for the accurate optimization of therapeutic options, we propose a comprehensive algorithm for multiple lung carcinomas based on a multidisciplinary approach, and investigate the prognosis of patients who underwent surgical resection. METHODS: Patients with multiple lung carcinomas who were treated at West China Hospital of Sichuan University from April, 2009 to December, 2017, were retrospectively identified. A comprehensive algorithm combining histologic assessment, molecular analysis, and imaging information was used to classify nodules as IPM or MPLC. The Kaplan-Meier method was used to estimate survival rates, and the relevant factors were evaluated using the log-rank test or Cox proportional hazards model. RESULTS: The study included 576 patients with 1,295 lung tumors in total. Significant differences were observed between the clinical features of 171 patients with IPM and 405 patients with MPLC. The final classification consistency was 0.65 and 0.72 compared with the criteria of Martini and Melamed (MM) and the American College of Chest Physicians (ACCP), respectively. Patients with independent primary tumors had better overall survival (OS) than patients with intra-pulmonary metastasis (HR =3.99, 95% CI: 2.86-5.57; P<0.001). Nodal involvement and radiotherapy were independent prognostic factors. CONCLUSIONS: The comprehensive algorithm was a relevant tool for classifying multifocal lung tumors as MPLC or IPM, and could help doctors with precise decision-making in routine clinical practice. Patients with multiple lesions without lymph node metastasis or without radiotherapy tended to have a better prognosis.

Establishment of Criteria for Molecular Differential Diagnosis of MPLC and IPM.

BACKGROUNDS: Differential diagnosis of multiple primary lung cancer (MPLC) and intrapulmonary metastasis (IPM) is one difficulty in lung cancer diagnosis, and crucial for establishment of treatment strategies and prognosis prediction. This study aims to establish the criteria for molecular differential diagnosis of synchronous MPLC and IPM by the next-generation sequencing (NGS) method. METHODS: Training cohort included 30 synchronous MPLC (67 samples) patients and 5 synchronous IPM (13 samples) patients with adenocarcinoma. Criteria of MPLC/IPM differential diagnosis were established by results from a NGS-based 605-gene panel test. Subsequently, 16 patients (36 samples) were recruited as the validation cohort to verify the criteria. RESULTS: IPM lesions showed a high degree of mutation overlap with an average concordance rate of 60.2% (range: 15.8%-91.7%). IPM lesions had at least three common alterations, including both high-frequency driver gene alterations and low-frequency gene alterations. In contrast, the average concordance rate of MPLC was 11.0% (range: 0.0%-100.0%), among which 66.7% (20/30) of patients had no common alterations (concordance rate: 0%). In the remaining 10 patients, 9 had only one overlapping alteration while 1 had two overlapping alterations, in which 6 patients had EGFR L858R overlapping mutation. Alterations were classified into trunk, shared, and branch subtypes. Branch alterations accounted for 94.4% of mutations in MPLC, while accounted for only 45.0% in IMP. In contrast, the ratio of trunk (38.3%) and shared (16.7%) alterations in IPM was significantly higher. The criteria for differentiating MPLC from IPM using 605-gene panel was established: 1) MPLC can be interpreted if no overlapping alterations is found; 2) MPLC is recommended if one overlapping high-frequency drive gene alteration and/or one overlapping low-frequency gene alteration are/is found; 3) IPM can be interpreted if more than three common alterations are found. Subsequently, 16 patients were recruited as the validation cohort in the single-blind manner to verify the criteria, and 14 MPLC and 2 IPM were identified, which was 100% consistent with the results from independent imaging and pathological diagnosis. CONCLUSIONS: NGS detection can distinguish synchronous MPLC from IPM and is a useful tool to assist differential diagnosis.

Survival rate and prognostic factors of surgically resected clinically synchronous multiple primary non-small cell lung cancer and further differentiation from intrapulmonary metastasis.

BACKGROUND: The diagnosis, staging, and therapeutic strategy for synchronous multiple primary non-small cell lung cancer (SMP-NSCLC) remain unclear. Distinguishing SMP-NSCLC from intrapulmonary metastasis is difficult but of great importance for selecting the surgical procedure and prognoses. METHODS: Fifty-two patients diagnosed with SMP-NSCLC according to the modified Martini-Melamed criteria in the thoracic surgery department of the China-Japan Friendship Hospital from November 2004 to December 2015 were enrolled in this retrospective study. A total of 106 tumors were subjected to pathological examination. Close follow-up and survival analysis were performed. RESULTS: The perioperative morbidity rate was 5.8%, with no cases of perioperative death. The overall 5-year survival rate was 40.6%, the cancer-specific 5-year survival rate was 54.5%, and the median survival time was 52 months. Older age (P=0.553), sex (P=0.600), smoking history (P=0.496), tumor distribution (P=0.461), video-assisted thoracoscopic surgery (VATS) (P=0.398), and adjuvant chemotherapy (P=0.078) did not affect survival. Preoperative percentage of forced expiratory volume in the first second (P=0.022), Charlson comorbidity index (P=0.034), surgical procedure (P=0.040), and highest pT stage (P=0.022) were independent risk factors in the multivariate analysis. Different pathological subtypes were identified in 13 of 18 cases of multiple adenocarcinomas. Different gene mutation types and correlations between tumors were identified through NGS in those with the same pathological subtype. CONCLUSIONS: Postoperative survival rates in SMP-NSCLC were satisfactory. Non-radical resection might improve the prognosis for patients with a tolerable general condition and pulmonary function. Higher pT stage might result in poorer survival rates. Larger sample size and future study are still needed to identify the prognostic factors. Comprehensive histologic assessment and next generation sequencing (NGS) could be effective methods for screening SMP-NSCLC.

Stage I synchronous multiple primary non-small cell lung cancer: CT findings and the effect of TNM staging with the 7th and 8th editions on prognosis.

BACKGROUND: Studies have reported that up to 8% of non-small cell lung cancers (NSCLC) involve multiple lesions; no detailed study has assessed the prognosis of early synchronous multiple primary non-small cell lung cancer (SMPNSCLC) (T1N0M0, T2aN0M0). We aimed to assess the spiral CT manifestations of SMPNSCLC during stage I and evaluate the effect of TNM staging with the 7th and 8th editions on the prognosis. METHODS: We retrospectively analyzed the data of patients who were examined, operated, and pathologically confirmed as having NSCLC from January 1, 2009, to December 31, 2010, and were followed-up for 5 years. The number of cases with stage I SMPNSCLC and solitary primary NSCLC (SPNSCLC) was 36 and 133 as per the 7th edition TNM staging system and 34 and 111 as per the 8th edition TNM staging system, respectively. The relationship between sex, age, smoking history, emphysema, surgical procedure, pathological type, tumor location, and tumor size was evaluated between the two groups, along with the correlation between prognosis and TNM staging with the 7th and 8th editions. RESULTS: A total of 1,948 cases of NSCLC underwent surgery, including 36 cases of stage I SMPNSCLC (77 lesions; 1.85%) with an age of onset of 44-86 years (median age, 60 years). The tumors primarily included adenocarcinoma (93.5%), with a diameter of 0.4-4.5 cm (median, 2.3 cm). CT indicated round/oval tumors in 81.8% cases, lobulation in 79.2% cases, spiculation sign in 70.1% cases, bronchial truncation sign in 31.2% cases, and pleural indentation in 75.3% cases. Moreover, CT indicated the presence of 36 (46.8%) solid nodules and 41 (53.2%) sub-solid nodules. With the 7th edition TNM staging system, the 5-year overall survival (OS) and disease-free survival (DFS) rates for stage ISMPNSCLC were 86.1% and 72.2%, respectively, which did not significantly differ from the prognosis of 133 cases of stage I SPNSCLC (P=0.587, P=0.273). With the 8th edition TNM staging system, the 5-year OS and DFS rates for stage I SMPNSCLC were 88.2% and 73.5%, respectively, which also did not significantly differ with the prognosis of 111 cases of stage I SPNSCLC (P=0.413, P=0.235). CONCLUSIONS: Adenocarcinoma was the main pathological type among the cases with stage I SMPNSCLC. Multiple synchronous lesions almost had the malignant characteristics of primary lung cancer, particularly the presence of single or multiple sub-solid nodules. Moreover, stage I SMPNSCLC has a similar prognosis as stage I SPNSCLC. The postoperative outcomes of stage I SMPNSCLC patients remained consistent regardless of whether the 7th or 8th edition TNM staging system was used for staging.

The equivalent efficacy of multiple operations for multiple primary lung cancer and a single operation for single primary lung cancer.

BACKGROUND: The incidence of synchronous and metachronous multiple primary lung cancers (MPLCs) has been increasing recently. The new multidisciplinary classification of lung adenocarcinoma and TNM Classification of Lung Cancer (7(th) edition, 2009), have improved the understanding of MPLC. Most researchers recommend that surgical therapy should be actively pursued if the patient's physical condition and lung function permit it and if a complete cure can be achieved. However, few studies have reported the long-term efficacy of surgical treatment for MPLC, which we explored in this study. METHODS: A total of 1,290 Lung cancer patients from a prospectively maintained database, treated by a single surgeon group between January 2000 and July 2013, at Beijing Cancer Hospital, Peking University, were reviewed. We retrospectively analyzed the clinical data of 31 patients diagnosed with MPLC out of 1290 lung cancer patients, focusing on long-term survival. RESULTS: MPLC patients accounted for 2.4% (31/1,290) of the patient cohort: 27 had synchronous MPLC (87.1%) and 4 had metachronous MPLC (12.9%). The 1-, 3- and 5-year postoperative survival rates were 100%, 75.8% and 75.8%. On stratification according to TNM stage, the 1-, 3- and 5-year of patients with stage I cancer (20 patients) were 100%, 77.2% and 77.2%, not statistically significant with those for the entire cohort (1,290 patients; 95.4%, 80.5% and 66.2%, P=0.455). CONCLUSIONS: When the patient's physical condition and tumor-related factors permit it, surgery should be the first choice of treatment for MPLC; it is associated with an equivalent efficacy to that of surgery for single primary lung cancer.