The role of surgery for invasive pulmonary aspergillosis in paediatric hemato-oncology patients-Can we better define it?

BACKGROUND: Invasive pulmonary aspergillosis (IPA) is a serious condition with high morbidity and mortality in paediatric patients with cancer, haematological diseases or immunodeficiencies with or without allogeneic haematopoietic stem cell transplantation (HSCT). The role of surgical intervention for the management of IPA has scarcely been investigated. OBJECTIVES: The aim of this study was to present a single center experience of management of IPA in paediatric patients of an oncological ward, to determine the short and long-term outcomes after thoracic surgical interventions, and to outline the indications of surgical interventions in selected patients. PATIENTS/METHODS: We conducted a retrospective study of 44 paediatric patients with proven and probable IPA treated in our institution between January 2003 and December 2021. The primary endpoint was the overall survival after surgical interventions. Secondary endpoints included post-operative morbidity and mortality. RESULTS: The median age at diagnosis of IPA in our cohort was 11.79 years (range 0.11-19.6). The underlying conditions were malignancies in 34 (77%) patients and haematological or immunological disorders with allogeneic HSCT in 9 (23%) patients. We performed thoracic surgical interventions in 10 (22.7%) patients. Most patients received a video assisted thoracic surgery. Only one patient died within 90 days after surgery with a median follow-up time of 50 months. No other major post-operative complications occurred. The calculated 5-year survival rate from IPA for patients after surgical intervention with curative intention was 57% and 56% for patients without (p = .8216). CONCLUSIONS: IPA resulted in relevant morbidity and mortality in our paediatric patient cohort. Thoracic surgical interventions are feasible and may be associated with prolonged survival as a part of multidisciplinary approach in selected paediatric patients with IPA. Larger scale studies are necessary to investigate the variables associated with the necessity of surgery.

Donor age over 55 is associated with worse outcome in lung transplant recipients with idiopathic pulmonary fibrosis.

BACKGROUND: Lung transplantation (LTx) remains the only efficient treatment for selected patients with end-stage pulmonary disease. The age limit for the acceptance of donor organs in LTx is still a matter of debate. We here analyze the impact of donor organ age and the underlying pulmonary disease on short- and long-term outcome and survival after LTx. METHODS: Donor and recipient characteristics of LTx recipients at our institution between 03/2003 and 12/2021 were analyzed. Statistical analysis was performed using SPSS and GraphPad software. RESULTS: In 230 patients analyzed, donor age ≥ 55 years was associated with a higher incidence of severe primary graft dysfunction (PGD2/3) (46% vs. 31%, p = 0.03) and reduced long-term survival after LTx (1-, 5- and 10-year survival: 75%, 54%, 37% vs. 84%, 76%, 69%, p = 0.006). Notably, this was only significant in recipients with idiopathic pulmonary fibrosis (IPF) (PGD: 65%, vs. 37%, p = 0.016; 1-, 5-, and 10-year survival: 62%, 38%, 16% vs. 80%, 76%, 70%, p = 0.0002 respectively). In patients with chronic obstructive pulmonary disease (COPD), donor age had no impact on the incidence of PGD2/3 or survival (21% vs. 27%, p = 0.60 and 68% vs. 72%; p = 0.90 respectively). Moreover, we found higher Torque-teno virus (TTV)-DNA levels after LTx in patients with IPF compared to COPD (X2 = 4.57, p = 0.033). Donor age ≥ 55 is an independent risk factor for reduced survival in the whole cohort and patients with IPF specifically. CONCLUSIONS: In recipients with IPF, donor organ age ≥ 55 years was associated with a higher incidence of PGD2/3 and reduced survival after LTx. The underlying pulmonary disease may thus be a relevant factor for postoperative graft function and survival. TRIAL REGISTRATION NUMBER DKRS: DRKS00033312.

Hybrid (Digital/Water Seal) Chest Drainage System - An Innovative Device for Patients with Anticipated Air Leaks.

BACKGROUND: To date, several chest drainage systems are available, such as digital drainage systems (DDS) and traditional systems with continuous suction or water seal. However, none of these systems were yet shown to be favorable in the treatment of complex situations such as persistent air leaks or residual spaces. We present in-vitro as well as clinical data of a novel hybrid drainage system consisting of an optimized digital drainage system (ODDS) and an underwater seal drainage system (UWSD). METHODS: For in-vitro analysis, a DDS and an ODDS were connected to a pleural cavity simulator. Different air leaks were produced and data on intrapleural pressure and air flow were analyzed. Furthermore, we tested the hybrid drainage system in 10 patients with potential air leaks after pulmonary surgery. RESULTS: In in-vitro analysis, we could show, that with advanced pump technology, pressure fluctuations caused by the drainage system when trying to maintain a set pressure level in patients with airleaks were much smaller when using an ODDS and could even be eliminated when using a fluid collection canister with sufficient buffer capacity. This minimized air leak boosts caused by the drainage system. Optimizing the auto-pressure regulation algorithms also led to a reduced airflow through the fistula and promoted rest. Switching to a passive UWSD also reduced the amount of airflow. Clinical application of the hybrid drainage system yielded promising results. CONCLUSION: The novel hybrid drainage system shows promising results in the treatment of patients with complex clinical situations such as persistent air leaks.

Robotic diaphragm plication: functional and surgical outcomes of a single-center experience.

BACKGROUND: Diaphragm plication remains the only effective treatment for diaphragm paralysis. Robot-assisted thoracoscopic (RATS) diaphragm plication combines advantages of open and thoracoscopic techniques. We present our experiences focussing on lung-function improvement and surgical outcome. METHODS: In this single-center retrospective study with comparative analysis, perioperative data of all patients who underwent RATS or thoracoscopic (VATS) diaphragm plication between 2015 and 2022 at our institution were assessed. Functional outcome was analysed with pre- and postoperative pulmonary function tests in sitting and supine position. RESULTS: We included 43 diaphragm plications, of which 31 were performed via RATS. Morbidity in the RATS- and VATS-cohort were 13 and 8%, respectively (p = 0.64), without any major complication (Clavien-Dindo ≥ III, 0%). Surgical time for RATS diaphragm plication was reduced drastically with a median operating time for the first 16 patients of 136 min (range 84-185) and 84 min (range 56-122) for the most recent 15 patients (p < 0.0001). Pulmonary function testing after RATS-plication showed a mean increase in vital capacity (VC) of 9% (SD 8, p < 0.0001) and of 7% (SD 9, p = 0.0009) in forced expiratory volume in 1 s (FEV1) when sitting and 9% (SD 8, p < 0.0001) for VC as well as 10% (SD 8, p = 0.0001) for FEV1 when in supine position. CONCLUSION: RATS diaphragm plication is a very safe and feasible approach, yielding good results in improving patients' pulmonary function. Further studies are required to elucidate possible advantages over VATS or open approaches.

Independent risk factors for an increased incidence of thromboembolism after lung transplantation.

BACKGROUND: Thromboembolism (TE) after lung transplantation (LTX) is associated with increased morbidity and mortality. The aim of this study is to analyze the incidence and outcome of venous and arterial thromboembolic complications and to identify independent risk factors. PATIENTS AND METHODS: We retrospectively analyzed the medical records of 221 patients who underwent LTX at our institution between 2002 and 2021. Statistical analysis was performed using SPSS and GraphPad software. RESULTS: 74 LTX recipients (33%) developed TE. The 30-days incidence and 12-months incidence were 12% and 23%, respectively. Nearly half of the patients (48%) developed pulmonary embolism, 10% ischemic stroke. Arterial hypertension (p = 0.006), a body mass index (BMI) > 30 (p = 0.006) and diabetes mellitus (p = 0.041) were independent predictors for TE. Moreover, a BMI of > 25 at the time of transplantation was associated with an increased risk for TE (43% vs. 32%, p = 0.035). At the time of LTX, 65% of the patients were older than 55 years. An age > 55 years also correlated with the incidence of TE (p = 0.037) and these patients had reduced overall post-transplant survival when the event occurred within the first postoperative year (59% vs. 72%, p = 0.028). CONCLUSIONS: The incidence of TE after LTX is high, especially in lung transplant recipients with a BMI > 25 and an age > 55 years as well as cardiovascular risk factors closely associated with the metabolic syndrome. As these patients comprise a growing recipient fraction, intensified research should focus on the risks and benefits of regular screening or a prolonged TE prophylaxis in these patients. Trial registration number DKRS: 00021501.

Outcome of Repeated Resection of Pulmonary Metastases for Renal Cell Cancer.

BACKGROUND: To date, many studies investigated results and prognostic factors of pulmonary metastasectomy (PM) in renal cell cancer (RCC). However, reports concerning repeated resection for patients with recurrent pulmonary metastases (RPM) are limited. In this study, we analyzed safety, efficacy, and prognostic factors for survival after PM focusing on RPM for RCC. PATIENTS AND METHODS: Clinical, operative, and follow-up data of patients who underwent PM or RPM for RCC in our institution were retrospectively collected and correlated with each other from January 2005 to December 2019. RESULTS: Altogether 154 oncological pulmonary resections in curative intention as PM or RPM were performed in 82 and 26 patients. Postoperative complications were similar in both groups (n = 22 [26.8%] vs. 4 [15.4%], p = 0.2). Zero mortality was documented up to the 30th postoperative day. RPM was not associated with decreased 5-year-survival compared with PM (66.2 vs. 57,9%, p = 0.5). Patients who underwent RPM for recurrent lung metastases had a better overall survival in comparison with the other treatments including chemotherapy, radiotherapy, immunotherapy, and best supportive care (p = 0.04). In the multivariate analysis, disease-free survival was identified as an independent prognostic factor for survival (hazard ratio: 0.969, 0.941-0.999, p = 0.04). CONCLUSION: RPM is a safe and feasible procedure. The resection of recurrent lung metastases shows to prolong survival in comparison with the other therapeutic options for selected patients with RCC.

[Resection of Solitary Lung Metastasis of Urinary Tract Transitional Cell Cancer Can Prolong Survival in Selected Patients]. / Die Resektion solitärer Lungenmetastasen des Urothelkarzinom kann das Überleben bei selektionierten Patienten verlängern.

There are only a few small published studies on pulmonary metastasectomy for urinary tract transitional cell carcinoma (TCC). In this study, we examined the long-term outcome and the prognostic survival factors associated with pulmonary metastasectomy of urinary tract TCC, as based on our centre's 20-year experience. Between 2000 and 2020, curative pulmonary metastasectomy was performed in 18 patients (14 males and 4 females). Clinical, demographical and surgical data were retrospectively analysed. The disease-free interval between treatment of the primary tumour and pulmonary metastasectomy ranged from one to 48 months. Survival analysis was conducted with the Kaplan-Meier method and log-rank test. The 3- and 5-year survival rates were 84.7% and 52.9%, respectively. Resection of solitary metastases was a positive and independent factor for survival (p = 0.04). Pulmonary metastasectomy of urinary tract TCC is associated with a favourable outcome and solitary metastasis is associated with long-term survival. Surgical resection of solitary pulmonary metastasis and repeated lung metastasectomy by pulmonary recurrence from a urinary tract TCC is feasible in selected patients.

[Robotic Diaphragm Plication]. / Roboterassistierte thorakoskopische Zwerchfellraffung.

Acquired unilateral hemidiaphragm elevation is characterised by dyspnoea, which is typically aggravated when lying down, bending over or during swimming. The most common causes are idiopathic or due to injury to the phrenic nerve during cervical or cardio-thoracic surgery. To date, surgical diaphragm plication remains the only effective treatment. The aim of the procedure is to plicate the diaphragm to restore its tension and thus improve breathing mechanics, increase the available space for the lung and reduce compression from abdominal organs. In the past, various techniques using open and minimally invasive approaches have been described. Robot-assisted thoracoscopic diaphragm plication combines the advantages of a minimally invasive approach with excellent visualisation and freedom of movement. It was shown to be a safe technique which is easy to establish and can significantly improve pulmonary function.

[Prevention, Diagnosis, Therapy, and Follow-up of Lung Cancer - Interdisciplinary Guideline of the German Respiratory Society and the German Cancer Society - Abridged Version]. / Prävention, Diagnostik, Therapie und Nachsorge des Lungenkarzinoms.

The current S3 Lung Cancer Guidelines are edited with fundamental changes to the previous edition based on the dynamic influx of information to this field:The recommendations include de novo a mandatory case presentation for all patients with lung cancer in a multidisciplinary tumor board before initiation of treatment, furthermore CT-Screening for asymptomatic patients at risk (after federal approval), recommendations for incidental lung nodule management , molecular testing of all NSCLC independent of subtypes, EGFR-mutations in resectable early stage lung cancer in relapsed or recurrent disease, adjuvant TKI-therapy in the presence of common EGFR-mutations, adjuvant consolidation treatment with checkpoint inhibitors in resected lung cancer with PD-L1 ≥ 50%, obligatory evaluation of PD-L1-status, consolidation treatment with checkpoint inhibition after radiochemotherapy in patients with PD-L1-pos. tumor, adjuvant consolidation treatment with checkpoint inhibition in patients withPD-L1 ≥ 50% stage IIIA and treatment options in PD-L1 ≥ 50% tumors independent of PD-L1status and targeted therapy and treatment option immune chemotherapy in first line SCLC patients.Based on the current dynamic status of information in this field and the turnaround time required to implement new options, a transformation to a "living guideline" was proposed.

[Surgery for Thoracic Malignancies during the COVID-19 Pandemic: a Case-control Study Investigating the Risk for Postoperative Complications]. / Onkologische Thoraxchirurgie während der COVID-19-Pandemie: eine Fallkontrollstudie zum Risiko für postoperative Komplikationen.

BACKGROUND: The COVID-19 pandemic led to a major disturbance in the health care system. Many elective operations were postponed, including surgical oncology cases. Besides the need to contain hospital resources, this was also due to concerns about the safety to perform surgery during the pandemic and the impact of perioperative infections on postoperative outcomes. In this study we investigate the safety of surgery for thoracic malignancies during the COVID-19 pandemic. METHODS: We retrospectively analysed the outcome of surgery for thoracic malignancies during the first, second and third waves of the COVID-19 pandemic (from 01.01. to 30.04.2020 and from 01.01. to 30.04.2021). As a control group we included the patients who received thoracic oncology surgeries during the same period in the last 2 years before the onset of the pandemic. The primary outcome was the rate of postoperative complications. RESULTS: 236 operations were included in the pandemic group and 227 operations in the control group. There was no statistically significant difference in the rate of postoperative minor complications (16.1% vs. 18.5%, p = 0.5395) or major complications (12.2% vs. 10.13 %, p = 0.5563). The risk to develop postoperative pulmonary complications was not higher in the pandemic group (odds ratio 1.193, 95% CI 0.6515-2.203, p = 0.8232). There were 5 cases with COVID-19 infection after the operation in the pandemic group. There was no difference in the rate of postoperative mortalities (2 (0.85%) vs. 1 (0.44%), p > 0.9999) There was no COVID-19 related mortality. CONCLUSION: Maintaining oncologic thoracic surgery during the COVID-19 pandemic is safe, feasible and not associated with increased risks of postoperative complications or mortalities.

[Expert Recommendation for the Implementation of Hyperthermic Intrathoracic Chemotherapy (HITOC) in Germany]. / Expertenempfehlung zur Anwendung der hyperthermen intrathorakalen Chemotherapie (HITOC) in Deutschland.

INTRODUCTION: During the last few years, hyperthermic intrathoracic chemotherapy (HITOC) has been performed in several departments for thoracic surgery in Germany. The objective of this expert recommendation is to provide elementary recommendations for a standardised HITOC treatment, which are based on clinical experiences and research data. METHODS: Between October and December 2018, a group of experts for thoracic surgery in five departments of thoracic surgery developed recommendations for the HITOC procedure in Germany. These experts were selected by the latest national survey for HITOC and had the most clinical experience with HITOC. All recommendations are based on clinical experience, the experts' research data and recent literature. RESULTS: All recommendations were evaluated by all participating departments in one consensus survey. Finally, a total of six main conclusions including a total of 17 recommendations were developed. For each recommendation, the strength of the consensus is presented in percentages. 100% agreement was established for nomenclature, technique, the chemotherapeutic agent, the perioperative management, the safety measures and the indications for HITOC. All experts recommended cisplatin as the first choice chemotherapeutic agent for HITOC. The dosage of cisplatin is specified in mg/m2 body surface area (BSA) and should be between 150 and 175 mg/m2 BSA. The volume of the perfusion fluid (approximately 4 - 5 l) seems to play a role for the concentration gradient of cisplatin and should therefore also be taken into account. CONCLUSIONS: These expert recommendations provide a standardised and consistent implementation of the HITOC procedure. On this basis, postoperative complications associated to HITOC should be reduced and comparison of the results should be improved.

Regional versus systemic analgesia in video-assisted thoracoscopic lobectomy: a retrospective analysis.

BACKGROUND: The optimal perioperative analgesic strategy in video-assisted thoracic surgery (VATS) for anatomic lung resections remains an open issue. Regional analgesic concepts as thoracic paravertebral or epidural analgesia were used as systemic opioid application. We hypothesized that regional anesthesia would provide improved analgesia compared to systemic analgesia with parenteral opioids in VATS lobectomy and would be associated with a lower incidence of pulmonary complications. METHODS: The study was approved by the local ethics committee (AZ 99/15) and registered (germanctr.de; DRKS00007529, 10th June 2015). A retrospective analysis of anesthetic and surgical records between July 2014 und February 2016 in a single university hospital with 103 who underwent VATS lobectomy. Comparison of regional anesthesia (i.e. thoracic paravertebral blockade (group TPVB) or thoracic epidural anesthesia (group TEA)) with a systemic opioid application (i.e. patient controlled analgesia (group PCA)). The primary endpoint was the postoperative pain level measured by Visual Analog Scale (VAS) at rest and during coughing during 120 h. Secondary endpoints were postoperative pulmonary complications (i.e. atelectasis, pneumonia), hemodynamic variables and postoperative nausea and vomiting (PONV). RESULTS: Mean VAS values in rest or during coughing were measured below 3.5 in all groups showing effective analgesic therapy throughout the observation period. The VAS values at rest were comparable between all groups, VAS level during coughing in patients with PCA was higher but comparable except after 8-16 h postoperatively (PCA vs. TEA; p < 0.004). There were no significant differences on secondary endpoints. Intraoperative Sufentanil consumption was significantly higher for patients without regional anesthesia (p < 0.0001 vs. TPVB and vs. TEA). The morphine equivalence postoperatively applicated until POD 5 was comparable in all groups (mean ± SD in mg: 32 ± 29 (TPVB), 30 ± 27 (TEA), 36 ± 30 (PCA); p = 0.6046). CONCLUSIONS: Analgesia with TEA, TPVB and PCA provided a comparable and effective pain relief after VATS anatomic resection without side effects. Our results indicate that PCA for VATS lobectomy may be a sufficient alternative compared to regional analgesia. TRIAL REGISTRATION: The study was registered (germanctr.de; DRKS00007529 ; 10th June, 2015).

[Postoperative Haemothorax Following Thoracic Surgery]. / Postoperative Blutung nach thoraxchirurgischen Eingriffen.

Postoperative haemothorax following thoracic surgery is a rare complication, but associated with a high mortality. In the literature, this complication occurs in 0.6 to 4.6% of patients and with a mortality of 5.1 to 17.8%. In minor cases, chest tube placement, application of fresh frozen plasma (FFP) or transfusion can be sufficient to control the situation. In severe cases, re-thoracotomy is mandatory. The most frequent origin of bleeding is a bronchial or intercostal vessel (21 and 16%) or the area of pleural adhesions that were separated (10.5%). The pulmonal artery or vein were the origin of bleeding in 16% of cases while in most cases (37%) active bleeding could no longer be detected. A positive effect on postoperative outcome is observed after an early reoperation.

[Surgical Therapy for Lung Cancer: Why it Should be Performed in High Volume Centres]. / Chirurgische Therapie des Lungenkarzinoms: Argumente für die Behandlung in großen Zentren.

Data on surgical lung cancer cases were extracted from the German Federal Statistics on Diagnosis-related groups (DRG) and a possible association between hospital volume and surgical mortality was explored. All treatment cases documented between 2005 and 2015 with the main diagnosis of lung cancer (International Classification of Disease code C34) and the German Operations and Procedure Key (OPS) codes 5-323 to 5-328 for anatomical lung resections were analysed. The treatment cases were assigned to hospital groups, defined according to the number of procedures performed per year. The total number of anatomical lung resections for the diagnosis of lung cancer increased by 24% from 9376 resections in 2005 to 11,614 resections in 2015. In 2015, 57% of anatomical lung resections in patients with lung cancer were performed in 47 high volume centres (hospitals with ≥ 75 resections/year); the remaining 43% of the resections were distributed among 271 hospitals performing fewer than 75 resections per year. In hospitals performing fewer than 25 procedures/year, hospital mortality was almost twice as high as in large centres with ≥ 75 resections per year (5.7 vs. 3.0%, mean value 2005 to 2015). In summary, our data indicate that a small number of high-volume hospitals perform the major part of lung resections of lung cancer in Germany with better survival as compared to low-volume hospitals. Based on current nationwide data a clear association between hospital volume and surgical mortality could be demonstrated.

Mediastinal staging by videomediastinoscopy in clinical N1 non-small cell lung cancer: a prospective multicentre study.

A quarter of patients with clinical N1 (cN1) non-small cell lung cancer (NSCLC) based on positron emission tomography-computed tomography (PET-CT) imaging have occult mediastinal nodal involvement (N2 disease). In a prospective study, endosonography alone had an unsatisfactory sensitivity (38%) in detecting N2 disease. The current prospective multicentre trial investigated the sensitivity of preoperative mediastinal staging by video-assisted mediastinoscopy (VAM) or VAM-lymphadenectomy (VAMLA).Consecutive patients with operable and resectable (suspected) NSCLC and cN1 after PET-CT imaging underwent VAM(LA). The primary study outcome was sensitivity to detect N2 disease. Secondary endpoints were the prevalence of N2 disease, negative predictive value (NPV) and accuracy of VAM(LA).Out of 105 patients with cN1 on imaging, 26% eventually developed N2 disease. Invasive mediastinal staging with VAM(LA) had a sensitivity of 73% to detect N2 disease. The NPV was 92% and accuracy 93%. Median number of assessed lymph node stations during VAM(LA) was 4 (IQR 3-5), and in 96%, at least three stations were assessed.VAM(LA) has a satisfactory sensitivity of 73% to detect mediastinal nodal disease in cN1 lung cancer, and could be the technique of choice for pre-resection mediastinal lymph node assessment in this patient group with a one in four chance of occult-positive mediastinal nodes after negative PET-CT.

[The Significance of Surgery for Oligometastatic and Oligoprogressive Non-small Cell Lung Cancer]. / Die Bedeutung der Chirurgie beim oligometastatischen und oligoprogressiven nicht kleinzelligen Lungenkarzinom.

An increased understanding of tumour biology as well as novel therapeutic options have led to a further differentiation of metastatic non-small cell lung cancer. Oligometastatic lung cancer has a relatively benign clinical course with few metastases, which are often confined to a single organ. To create the best outcomes, the ideal treatment must be used for each individual tumor biology, with consideration of the different treatment modalities. Surgery is of increasing significance in curative treatment concepts in metastatic lung cancers. In analogy to oligometastatic disease, the term "oligoprogression" has emerged in recent years. This describes a state in which metastatic lung cancers which express sensitizing mutations show progression of disease only at a limited number of anatomical sites whilst under therapy with tyrosine kinase inhibitors. Current studies have shown encouraging results for surgical therapy in combination with systemic therapy of both oligometastatic and oligoprogressive disease in well selected patients. It remains to be determined whether the observed survival benefits are based on the favourable tumour biology or the applied treatment modalities. Moreover, robust molecular markers have to be determined to identify patients who will benefit from aggressive surgical treatment, in order to avoid overtreatment.

Spatio-temporal mutation profiles of case-matched colorectal carcinomas and their metastases reveal unique de novo mutations in metachronous lung metastases by targeted next generation sequencing.

BACKGROUND: Targeted next generation sequencing (tNGS) has become part of molecular pathology diagnostics for determining RAS mutation status in colorectal cancer (CRC) patients as predictive tool for decision on EGFR-targeted therapy. Here, we investigated mutation profiles of case-matched tissue specimens throughout the disease course of CRC, to further specify RAS-status dynamics and to identify de novo mutations associated with distant metastases. METHODS: Case-matched formalin-fixed and paraffin-embedded (FFPE) resection specimens (n = 70; primary tumours, synchronous and/or metachronous liver and/or lung metastases) of 14 CRC cases were subjected to microdissection of normal colonic epithelial, primary and metastatic tumour cells, their DNA extraction and an adapted library protocol for limited DNA using the 48 gene TruSeq Amplicon Cancer PanelTM, MiSeq sequencing and data analyses (Illumina). RESULTS: By tNGS primary tumours were RAS wildtype in 5/14 and mutated in 9/14 (8/9 KRAS exon 2; 1/9 NRAS Exon 3) of cases. RAS mutation status was maintained in case-matched metastases throughout the disease course, albeit with altered allele frequencies. Case-matched analyses further identified a maximum of three sequence variants (mainly in APC, KRAS, NRAS, TP53) shared by all tumour specimens throughout the disease course per individual case. In addition, further case-matched de novo mutations were detected in synchronous and/or metachronous liver and/or lung metastases (e.g. in APC, ATM, FBXW7, FGFR3, GNAQ, KIT, PIK3CA, PTEN, SMAD4, SMO, STK11, TP53, VHL). Moreover, several de novo mutations were more frequent in synchronous (e.g. ATM, KIT, PIK3CA, SMAD4) or metachronous (e.g. FBXW7, SMO, STK11) lung metastases. Finally, some de novo mutations occurred only in metachronous lung metastases (CDKN2A, FGFR2, GNAS, JAK3, SRC). CONCLUSION: Together, this study employs an adapted FFPE-based tNGS approach to confirm conservation of RAS mutation status in primary and metastatic tissue specimens of CRC patients. Moreover, it identifies genes preferentially mutated de novo in late disease stages of metachronous CRC lung metastases, several of which might be actionable by targeted therapies.