Ectopic pancreas tissue in the posterior mediastinum.

The occurrence of ectopic pancreas in the mediastinum is rare. Herein, we report a 22-year-old female who presented with right shoulder pain, dysphagia, fever and headaches. Chest computer tomography revealed a mass in the posterior mediastinum with accompanying signs of acute mediastinitis. Needle biopsy and fine-needle aspiration revealed ectopic gastral tissue and ectopic pancreas tissue, respectively. Surgical resection was attempted due to recurring acute pancreatitis episodes. However, due to chronic-inflammatory adhesions of the mass to the tracheal wall, en-bloc resection was not possible without major tracheal resection. Since then, recurring pancreatitis episodes have been treated conservatively with antibiotics. We report this case due to its differing clinical and radiological findings in comparison to previous case reports, none of which pertained a case of ectopic pancreas tissue in the posterior mediastinum with recurring acute pancreatitis and mediastinitis.

Postoperative Hiatal Hernia after Ivor Lewis Esophagectomy-A Growing Problem in the Age of Minimally Invasive Surgery.

BACKGROUND: Even though minimally invasive esophagectomy is a safe and oncologically effective procedure, several authors have reported an increased risk of postoperative hiatal hernia (PHH). This study evaluates the incidence and risk factors of PHH after hybrid minimally invasive (HMIE) versus open esophagectomy (OE). METHODS: A retrospective single-center analysis was performed on patients who underwent Ivor Lewis esophagectomy between January 2009 and April 2018. Computed tomography scans and patient files were reviewed to identify the PHH. RESULTS: 306 patients were included (152 HMIE; 154 OE). Of these, 23 patients (8%) developed PHH. Most patients (13/23, 57%) were asymptomatic at the time of diagnosis and only 4 patients (17%) presented in an emergency setting with incarceration. The rate of PHH was significantly higher after HMIE compared to OE (13.8% vs. 1.3%, p < 0.001). No other risk factors for the development of PHH were identified in uni- or multi-variate analysis. Surgical repair of PHH was performed in 19/23 patients (83%). The recurrence rate of PHH after surgical repair was 32% (6/19 patients). CONCLUSIONS: The development of PHH is a relevant complication after hybrid minimally invasive esophagectomy. Although most patients are asymptomatic, surgical repair is recommended to avoid incarceration with potentially fatal outcomes. Innovative techniques for the prevention and repair of PHH are urgently needed.

Oncological recurrence following pathological complete response after neoadjuvant treatment in patients with esophageal cancer - a retrospective cohort study.

BACKGROUND: To evaluate recurrence in patients with post-neoadjuvant pathological complete response (pCR) and in patients with complete response of primary tumor but persisting lymphatic spread of disease (non-pCR, ypT0ypN +) of esophageal cancer. METHODS: Seventy-five patients (63 pCR, 12 non-pCR) were analyzed retrospectively. Pattern and incidence of local and distant recurrence as well as the impact on overall (OS) and disease-free survival (DFS) were evaluated. The efficacy of neoadjuvant chemotherapy according to FLOT protocol was compared to neoadjuvant chemoradiation according to CROSS protocol. RESULTS: In the pCR group, isolated local recurrence was diagnosed in 3%, while no isolated local recurrence was observed in the non-pCR group due to the high incidence of distant recurrence. Distant recurrence was most common in both cohorts (isolated distant recurrence: pCR group 10% to non-pCR group 55%; simultaneous distant and local recurrence: pCR group 3% to non-pCR group 18%). Median time to distant recurrence was 5.5 months, and median time to local recurrence was 8.0 months. Cumulative incidence of distant recurrence (with and without simultaneous local recurrence) was 16% (± 6%) in pCR patients and 79% (± 13%) in non-pCR patients (hazard ratio (HR) 0.123) estimated by Kaplan-Meier method. OS (HR 0.231) and DFS (HR 0.226) were significantly improved in patients with pCR compared to patients with non-pCR. Advantages for FLOT protocol compared to CROSS protocol, especially with regard to distant control of disease (HR 0.278), were observed (OS (HR 0.361), DFS (HR 0.226)). CONCLUSION: Distant recurrence is the predominant site of treatment failure in patients with pCR and non-pCR grade 1a regression, whereby recurrence rates are much higher in patients with non-pCR.

Proximal gastrectomy and double-tract reconstruction vs total gastrectomy in gastric and gastro-esophageal junction cancer patients - a systematic review and meta-analysis protocol (PROSPERO registration number: CRD42021291500).

BACKGROUND: In Germany and Western Europe, gastroesophageal junction cancer (AEG) and proximal gastric cancer are currently treated with (transhiatal-extended) total gastrectomy (TG) according to the latest treatment guidelines. TG leads to a severe and long-lasting impairment of postoperative health-related quality of life (HRQoL) of the treated patients. Recent studies have suggested that HRQoL of these patients could be improved by proximal gastrectomy with double-tract reconstruction (PG-DTR) without compromising oncologic safety. Our aim is therefore to conduct a randomized controlled non-inferiority trial comparing PG-DTR with TG in AEG II/III and gastric cancer patients with overall survival as primary endpoint and HRQoL as key secondary endpoint. METHODS: This protocol is written with reference to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P 2015) statement. We will conduct searches in the electronic databases MEDLINE, Web of Science Core Collection, ScienceDirect, and Cochrane Library. We will also check references of relevant studies and perform a cited reference research. Titles and abstracts of the records identified by the searches will be screened, and full texts of all potentially relevant articles will be obtained. We will consider randomized trials and non-randomized studies. The selection of studies, data extraction, and assessment of risk of bias of the included studies will be conducted independently by two reviewers. Meta-analysis will be performed using RevMan 5.4 (Review Manager (RevMan) Version 5.4, The Cochrane Collaboration). DISCUSSION: This systematic review will identify the current study pool concerning the comparison of TG and PG-DTR and help to finally refine the research questions and to allow an evidence-based trial design of the planned multicenter randomized-controlled trial. ETHICS AND DISSEMINATION: Ethical approval is not required for this systematic review. Study findings will be shared by publication in a peer-reviewed journal. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021291500.

Circulating Epithelial Cells in Patients with Intraductal Papillary Mucinous Neoplasm of the Pancreas.

Intraductal papillary mucinous neoplasm (IPMN) is the most common pancreatic cyst and a precursor of pancreatic cancer (PDAC). Since PDAC has a devastatingly high mortality rate, the early diagnosis and treatment of any precursor lesion are rational. The safety of the existing guidelines on the clinical management of IPMN has been criticized due to unsatisfactory sensitivity and specificity, showing the need for further markers. Blood obtained from patients with IPMN was therefore subjected to size-based isolation of circulating epithelial cells (CECs). We isolated CECs and evaluated their cytological characteristics. Additionally, we compared Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations in CECs and the primary IPMN tissue, since KRAS mutations are very typical for PDAC. Samples from 27 IPMN patients were analyzed. In 10 (37%) patients, CECs were isolated and showed a hybrid pattern of surface markers involving both epithelial and mesenchymal markers, suggesting a possible EMT process of the cells. Especially, patients with high-grade dysplasia in the main specimen were all CEC-positive. KRAS mutations were also present in CECs but less common than in IPMN tissue. The existence of CEC in IPMN patients offers additional blood-based research possibilities for IMPN biology.

Cancer-associated Macrophage-like Cells in Patients with Non-metastatic Adenocarcinoma of the Esophagus - Cytomorphological Heterogeneity.

Introduction: Esophageal adenocarcinoma (EAC) often recurs systemically despite therapy with a curative aim. New diagnostic and therapeutic approaches are urgently needed. A promising field is liquid biopsy, meaning the investigation of tumor-associated cells in the peripheral blood, for example cancer-associated macrophage-like cells (CAML). The aim of this multicentric study was to investigate the presence and cytomorphological appearance of CAML in patients with non-metastatic and operable esophageal cancer. Methods: Blood samples from 252 patients with locally advanced EAC were obtained before starting curative treatment including surgery, and then processed using ScreenCell® filtration devices. Cytological analysis was performed via May-Grünwald-Giemsa staining. CAML were defined by their morphological characteristics. We also performed immunofluorescence staining with the mesenchymal marker vimentin on a subset of our study cohort. Results: We detected cytomorphologically heterogeneous CAML in 31.8% (n=80) patients. Their presence and cell count did not correlate significantly with pretherapeutic cTNM. Even in patients with small tumors and no lymph-node infiltration, cell counts were high. CAML showed heterogenous staining patterns for vimentin. Conclusion: This is one of the first studies demonstrating the presence and phenotype of CAML in a uniquely broad cohort of EAC patients. As they are believed to be representatives of the inflammatory tumor microenvironment shed into the bloodstream, their presence in non-metastatic EAC is a promising finding.

Systematic review and meta-analysis comparing proximal gastrectomy with double-tract-reconstruction and total gastrectomy in gastric and gastroesophageal junction cancer patients: Still no sufficient evidence for clinical decision-making.

BACKGROUND: To compare proximal gastrectomy with double-tract reconstruction and total gastrectomy in patients with gastroesophageal junction (AEG II-III) and gastric cancer. METHODS: We conducted systematic searches in Medline, Web of Science, and Cochrane Library until December 20, 2021 (PROSPERO registration number: CRD42021291500). Risk of bias was assessed using the revised Cochrane risk of bias tool and the ROBINS-I tool, as applicable. Evidence was rated by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. RESULTS: One randomized controlled trial (RCT) and 13 non-RCTs with 1,317 patients (715 patients with total gastrectomy and 602 patients with proximal gastrectomy with double-tract reconstruction) were included. Patients treated by total gastrectomy had a significantly higher proportion of advanced cancer stages International Union Against Cancer IB-III (odds ratio: 0.68, 95% confidence interval: 0.51-0.91, P = .01). This heterogeneity biases the observed improved overall survival of patients after proximal gastrectomy with double-tract reconstruction (odds ratio: 0.67, 95% confidence interval: 0.44-1.01, P = .05). Both procedures were comparably efficient regarding perioperative parameters. Postoperative/preoperative bodyweight ratio (mean difference: 3.56, 95% confidence interval: 1.32-5.79, P = .002), postoperative/preoperative serum-hemoglobin ratio (mean difference 3.73, 95% confidence interval: 1.59-5.88, P < .001), and postoperative serum vitamin B12 levels (mean difference 42.46, 95% confidence interval: 6.37-78.55, P = .02) were superior after proximal gastrectomy with double-tract reconstruction, while postoperative/preoperative serum-albumin ratio (mean difference 1.24, 95% confidence interval: -4.76 to 7.24, P = .69) and postoperative/preoperative serum total protein ratio (mean difference 1.12, 95% confidence interval: -2.77 to 5.00, P = .57) were not different. Health-related quality of life data were reported in only 2 studies, which found no significant advantages for proximal gastrectomy with double-tract reconstruction. CONCLUSION: Proximal gastrectomy with double-tract reconstruction offers advantages in postoperative nutritional parameters compared to total gastrectomy (GRADE: moderate quality of evidence). Oncological effectiveness of proximal gastrectomy with double-tract reconstruction cannot be assessed (GRADE: very low quality of evidence). Further thoroughly planned randomized controlled trials in Western patient cohorts are necessary to improve treatment for gastric cancer patients.

Pathological complete response in multimodal treatment of esophageal cancer: a retrospective cohort study.

To evaluate pathological complete response (pCR, ypT0ypN0) after neoadjuvant treatment compared with non-complete response (non-CR) in patients with esophageal cancer (EC), and 393 patients were retrospectively analyzed. Survival probability was analyzed in patients with: (i) pCR vs non-CR; (ii) complete response of the primary tumor but persisting lymphatic metastases (non-CR-T0N+) and (iii) pCR and tumor-free lymphnodes exhibiting signs of postneoadjuvant regression vs. no signs of regression. (i) Median overall survival (mOS) was favorable in patients with pCR (pCR: mOS not reached vs. non-CR: 41 months, P < 0.001). Multivariate analysis revealed that grade of regression was not an independent predictor for prolonged survival. Instead, the achieved postneoadjuvant TNM-stage (T-stage: Hazard ratio [HR] ypT3-T4 vs. ypT0-T2: 1.837; N-stage: HR ypN1-N3 vs. ypN0: 2.046; Postneoadjuvant M-stage: HR ypM1 vs. ycM0: 2.709), the residual tumor (R)-classification (HR R1 vs. R0: 4.195) and the histologic subtype of EC (HR ESCC vs. EAC: 1.688) were prognostic factors. Patients with non-CR-T0N+ have a devastating prognosis, similar to those with local non-CR and lymphatic metastases (non-CR-T + N+) (non-CR-T0N+: 22.0 months, non-CR-T + N-: mOS not reached, non-CR-T + N+: 23.0 months; P-values: non-CR-T0N+ vs. non-CR-T + N-: 0.016; non-CR-T0N+ vs. non-CR-T + N+: 0.956; non-CR-T + N- vs. non-CR-T + N+: <0.001). Regressive changes in lymphnodes after neoadjuvant treatment did not influence survival-probability in patients with pCR (mOS not reached in each group; EAC-patients: P = 0.0919; ESCC-patients: P = 0.828). Particularly, the achieved postneoadjuvant ypTNM-stage influences the survival probability of patients with EC. Patients with non-CR-T0N+ have a dismal prognosis, and only true pathological complete response with ypT0ypN0 offers superior survival probabilities.

Ligamentum teres augmentation (LTA) for hiatal hernia repair after minimally invasive esophageal resection: a new use for an old structure.

PURPOSE: Hiatal hernias with intrathoracic migration of the intestines are serious complications after minimally invasive esophageal resection with gastric sleeve conduit. High recurrence rates have been reported for standard suture hiatoplasties. Additional mesh reinforcement is not generally recommended due to the serious risk of endangering the gastric sleeve. We propose a safe, simple, and effective method to close the hiatal defect with the ligamentum teres. METHODS: After laparoscopic repositioning the migrated intestines, the ligamentum teres is dissected from the ligamentum falciforme and the anterior abdominal wall. It is then positioned behind the left lobe of the liver and swung toward the hiatal orifice. Across the anterior aspect of the hiatal defect it is semi-circularly fixated with non-absorbable sutures. Care should be taken not to endanger the blood supply of the gastric sleeve. RESULTS: We have used this technique for a total of 6 patients with hiatal hernias after hybrid minimally invasive esophageal resection in the elective (n = 4) and emergency setting (n = 2). No intraoperative or postoperative complications have been observed. No recurrence has been reported for 3 patients after 3 months. CONCLUSION: Primary suture hiatoplasties for hiatal hernias after minimally invasive esophageal resection can be technically challenging, and high postoperative recurrence rates are reported. An alternative, safe method is needed to close the hiatal defect. Our promising preliminary experience should stimulate further studies regarding the durability and efficacy of using the ligamentum teres hepatis to cover the hiatal defect.

[Mesh Implantation in Anti-Reflux and Hiatal Hernia Surgery - Contra Statement]. / Netzimplantation bei der Chirurgie der Hiatushernie und bei der Anti-Reflux-Chirurgie ­ Kontra-Statement.

In the surgical treatment of gastroesophageal reflux disease and of hiatal hernias, the high rate of recurrence of hiatal hernias is a central problem. Against this background, various, primarily alloplastic, meshes are used to augment suture closure on the esophageal hiatus. Very different results have been reported in the past and the use of meshes in hiatus reconstruction is controversial. In addition to the frequency of recurrences, reports about complications of mesh augmentation are in the foreground. On the basis of several prospective randomised double-blinded comparative studies and meta-analyses (class Ia and Ib evidence), the current data do not show any advantages of mesh-augmented hiatoplasty for the prevention of recurrence of hiatal hernia. At the same time, there exist reports of more long-term postoperative complications, especially dysphagia, after use of meshes for augmentation of hiatus reconstruction. Therefore, routine use of mesh augmentation for hiatus reconstruction is currently not recommended.

Cytopathological Heterogeneity of Circulating Tumor Cells in Non-metastatic Esophageal Adenocarcinoma.

BACKGROUND/AIM: The presence of circulating tumor cells (CTC) has been reported to have an impact on prognosis in different tumor entities. Little is known about CTC morphology and heterogeneity. PATIENTS AND METHODS: In a multicenter setting, pre-therapeutic peripheral blood specimens were drawn from patients with non-metastatic esophageal adenocarcinoma (EAC). CTCs were captured by size-based filtration (ScreenCell®), subsequently Giemsa-stained and evaluated by two trained readers. The isolated cells were categorized in groups based on morphologic criteria. RESULTS: Small and large single CTCs, as well as CTC-clusters, were observed in 69.2% (n=81) of the 117 specimens; small CTCs were observed most frequently (59%; n=69), followed by large CTCs (40%; n=47) and circulating cancer-associated macrophage-like cells (CAMLs; 34.2%, n=40). Clusters were rather rare (12%; n=14). CTC/CAML were heterogeneous in the cohort, but also within one specimen. Neither the presence of the CTC subtypes/CAMLs nor the exact cell count were associated with the primary clinical TNM stage. CONCLUSION: Morphologically heterogenic CTCs and CAMLs are present in patients with non-metastatic, non-pretreated EAC.

Pattern of Recurrence and Patient Survival after Perioperative Chemotherapy with 5-FU, Leucovorin, Oxaliplatin and Docetaxel (FLOT) for Locally Advanced Esophagogastric Adenocarcinoma in Patients Treated Outside Clinical Trials.

BACKGROUND: The 5-FU, Leucovorin, Oxaliplatin and Docetaxel (FLOT) protocol provides superior oncologic results compared to other perioperative chemotherapeutic protocols for the treatment of non-metastatic esophagogastric cancer (EGAC). Survival and the pattern of recurrence of EGAC after FLOT and curative tumor resection are analyzed in a collective of patients treated outside clinical trials. METHODS: Two-hundred-seventy-seven patients with EGAC (cT3-4 and/or cN+) were treated with perioperative FLOT-chemotherapy plus curative surgery between 2009 and 2018. Data were analyzed retrospectively from a prospective database. RESULTS: Two-hundred-twenty-eight patients were included in the analysis. Postoperative in-hospital mortality was 2%. The median survival was 61-months, and median recurrence-free survival was 42 months. Multivariate analysis identified postoperative nodal status and T-stage as independent predictors of improved overall and recurrence-free survival. Administration of adjuvant chemotherapy failed to be significant for overall survival but was an independent predictor of recurrence-free survival. Recurrence occurred after a median of 9 months (range 1-46 months). Eighty-nine percent of recurrence occurred during the first 24 months. The rate of local recurrence was low. After surgery for gastric cancer, the major recurrence site was peritoneal carcinomatosis (56%), while esophageal cancer recurred mostly as metastasis to distant organs (78%). The specific site of recurrence had no impact on overall survival time. CONCLUSION: Real-life application of FLOT shows oncologic results comparable to clinical trials. Recurrence after FLOT and surgery for EGAC occurs predominantly early within the first two years after surgery and in the form of distant organ metastasis for esophageal tumors or peritoneal carcinomatosis for gastric tumors.

Short-term and long-term outcomes of oesophagogastric surgery for cancer in obese and normal weight patients.

BACKGROUND: Obesity is generally considered to be associated with worse surgical outcome and impaired oncological prognosis. The impact of pre-therapeutic body mass index (BMI) in patients with oesophagogastric cancer on the surgical outcome is controversially discussed. METHODS: We retrospectively examined 730 patients who had undergone curative treatment for oesophagogastric cancer at the Medical Center of the University of Freiburg (1996-2015). Patients were divided in groups according to pre-therapeutic BMI (underweight (UW): <18.5 kg/m2 ; normal weight (NW): 18.5-25 kg/m2 ; overweight (OW): 25-30 kg/m2 ; and obese (OB): >30 kg/m2 ). RESULTS: Median BMI was 24.7 kg/m2 . Forty-two patients were UW, 337 NW, 263 OW and 84 OB. No significant differences between the groups (UW/NW/OW/OB) in operating time, hospital stay, perioperative complication rate and in-hospital mortality were found. Pre-therapeutic BMI was significantly associated with 5-year survival (UW: 22%, NW: 37%, OW: 51%, OB: 50%, P < 0.001). Multivariate analysis identified UW/NW (BMI <25 kg/m2 ) as an independent risk factor for poor survival (relative risk 1.38, P = 0.001) among high American Society of Anesthesiologists score, old age, positive resection margin and high cancer stage according to the Union Internationale Contre le Cancer (UICC). CONCLUSION: In oesophagogastric cancer, OW and OB patients can be treated surgically without impaired perioperative outcome and expect improved long-term survival compared to patients with a BMI <25 kg/m2 .

Hybrid Minimally Invasive Esophagectomy-Surgical Technique and Results.

BACKGROUND: Hybrid minimally invasive esophagectomy (HMIE) has been proven to be superior when compared with open esophagectomy, with a significant reduction of postoperative morbidity. In HMIE, the laparotomy is replaced by a minimally invasive laparoscopic approach. The radical mediastinal resection plus reconstruction is performed by a thoracic approach through a muscle-sparing thoracotomy. In this instructional article, we describe the surgical technique of HMIE in detail in order to facilitate possible adoption of the procedure by other surgeons. In addition, we give the monocentric results of our own practice. METHODS: Between 2013 and 2018, HMIE was performed in 157 patients. The morbidity and mortality data of the procedure is shown in a retrospective monocentric analysis. RESULTS: Overall, 54% of patients had at least one perioperative complication. Anastomotic leak was evident in 1.9%, and a single patient had focal conduit necrosis of the gastric pull-up. Postoperative pulmonary morbidity was 31%. Pneumonia was found in 17%. The 90 day mortality was 2.5%. Wound infection rate was 3%, and delayed gastric emptying occurred in 17% of patients. In follow up, 12.7% presented with diaphragmatic herniation of the bowel, requiring laparoscopic hernia reduction and hiatal reconstruction and colopexy several months after surgery. CONCLUSION: HMIE is a highly reliable technique, not only for the resection part but especially in terms of safety in reconstruction and anastomosis. For esophageal surgeons with experience in minimally invasive anti-reflux procedures and obesity surgery, HMIE is easy and fast to learn and adopt.

Non-Metastatic Esophageal Adenocarcinoma: Circulating Tumor Cells in the Course of Multimodal Tumor Treatment.

BACKGROUND: Isolation of circulating tumor cells (CTC) holds the promise to improve response-prediction and personalization of cancer treatment. In this study, we test a filtration device for CTC isolation in patients with non-metastatic esophageal adenocarcinoma (EAC) within recent multimodal treatment protocols. METHODS: Peripheral blood specimens were drawn from EAC patients before and after neoadjuvant chemotherapy (FLOT)/chemoradiation (CROSS) as well as after surgery. Filtration using ScreenCell® devices captured CTC for cytologic analysis. Giemsa-stained specimens were evaluated by a cytopathologist; the cut-off was 1 CTC/specimen (6 mL). Immunohistochemistry with epithelial (pan-CK) and mesenchymal markers (vimentin) was performed. RESULTS: Morphologically diverse malignant CTCs were found in 12/20 patients in at least one blood specimen. CTCs were positive for both vimentin and pan-CK. More patients were CTC positive after neoadjuvant therapy (6/20 vs. 9/15) and CTCs per/ml increased in most of the CTC-positive patients. After surgery, 8/13 patients with available blood specimens were still CTC positive. In clinical follow-up, 5/9 patients who died were CTC-positive. CONCLUSIONS: Detection of CTC by filtration within multimodal treatment protocols of non-metastatic EAC is feasible. The rate of CTC positive findings and the quantity of CTCs changes in the course of multimodal neoadjuvant chemoradiation/chemotherapy and surgery.

Author Correction: Pancreatic cancer: Circulating Tumor Cells and Primary Tumors show Heterogeneous KRAS Mutations.

A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.

Pancreatic cancer: Circulating Tumor Cells and Primary Tumors show Heterogeneous KRAS Mutations.

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease. Circulating tumor cells (CTC) in the blood are hypothesized as the means of systemic tumor spread. Blood obtained from healthy donors and patients with PDAC was therefore subject to size-based CTC-isolation. We additionally compared Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations in pancreatic CTC and corresponding tumors, and evaluated their significance as prognostic markers. Samples from 68 individuals (58 PDAC patients, 10 healthy donors) were analyzed; CTCs were present in patients with UICC stage IA-IV tumors and none of the controls (p < 0.001). Patients with >3 CTC/ml had a trend for worse median overall survival (OS) than patients with 0.3­3 CTC/ml (P = 0.12). Surprisingly, CTCs harbored various KRAS mutations in codon 12 and 13. Patients with a KRAS G12V mutation in their CTC (n = 14) had a trend to better median OS (24.5 months) compared to patients with other (10 months), or no detectable KRAS mutations (8 months; P = 0.04). KRAS mutations in CTC and corresponding tumor were discordant in 11 of 26 "tumor-CTC-pairs" (42%), while 15 (58%) had a matching mutation; survival was similar in both groups (P = 0.36). Genetic characterization, including mutations such as KRAS, may prove useful for prognosis and understanding of tumor biology.